Edit Intro section of Cloud Admin Guide Compute chapter
Remove deprecated information Correct figures Edit grammar and style Introduce refs to other guides Change Nova to Compute Change-Id: Icbf1a38e2d233ac3255858246b471a0c849c405b Partial-bug: #1222003 Author: Nermina Miller
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xml:id="ch_introduction-to-openstack-compute">
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<?dbhtml stop-chunking?>
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<title>Compute</title>
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<para>Compute provides a tool that lets you orchestrate a cloud. By using Nova, you can run instances, manage networks, and manage access
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to the cloud through users and projects. Nova provides software
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that enables you to control an Infrastructure as a Service (IaaS) cloud
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computing platform and is similar in scope to Amazon EC2 and
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Rackspace Cloud Servers.</para>
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<para>The Compute service, code-named Nova, provides a tool that lets you orchestrate a cloud.
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By using Compute, you can run instances, manage networks, and manage access to the cloud
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through users and projects. Compute provides software that enables you to control an
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Infrastructure as a Service (IaaS) cloud computing platform.</para>
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<section xml:id="section_compute-intro">
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<title>Introduction to Compute</title>
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<para>Compute does not include any virtualization software;
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@ -21,190 +20,139 @@
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API.</para>
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<section xml:id="section_hypervisors">
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<title>Hypervisors</title>
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<para>OpenStack Compute requires a hypervisor. Compute
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controls hypervisors through an API server. To select a hypervisor, you must prioritize and make decisions
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based on budget,
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resource constraints,
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supported features, and required technical
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specifications. The majority of development is done
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with the KVM and Xen-based hypervisors. For a detailed list of features and support across the
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hypervisors, see <link
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<para>Compute requires a hypervisor. Compute controls hypervisors through an API server.
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To select a hypervisor, you must prioritize and make decisions based on budget,
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resource constraints, supported features, and required technical specifications. The
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majority of development is done with the KVM and Xen-based hypervisors. For a
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detailed list of features and support across the hypervisors, see <link
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xlink:href="http://wiki.openstack.org/HypervisorSupportMatrix"
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>http://wiki.openstack.org/HypervisorSupportMatrix</link>.
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With OpenStack Compute, you can
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orchestrate clouds using multiple hypervisors in
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different zones. The types of virtualization standards
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that can be used with Compute include:</para>
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>http://wiki.openstack.org/HypervisorSupportMatrix</link>. </para>
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<para>With Compute, you can orchestrate clouds using multiple hypervisors in different
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availability zones. The types of virtualization standards that can be used with
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Compute include:</para>
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<itemizedlist>
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<listitem>
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<para><link
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xlink:href="http://www.linux-kvm.org/page/Main_Page"
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>KVM</link> - Kernel-based Virtual
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Machine</para>
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<para><link xlink:href="https://wiki.openstack.org/wiki/Baremetal"
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>Baremetal</link>.</para>
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</listitem>
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<listitem>
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<para><link
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xlink:href="http://lxc.sourceforge.net/"
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>LXC</link> - Linux Containers (through
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libvirt)</para>
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<para><link xlink:href="http://www.microsoft.com/en-us/server-cloud/hyper-v-server/default.aspx">Hyper-V</link></para>
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</listitem>
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<listitem>
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<para><link
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xlink:href="http://wiki.qemu.org/Manual"
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>QEMU</link> - Quick EMUlator</para>
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<para>Kernel-based Virtual Machine (<link
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xlink:href="http://www.linux-kvm.org/page/Main_Page">KVM</link>).</para>
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</listitem>
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<listitem>
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<para><link
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xlink:href="http://user-mode-linux.sourceforge.net/"
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>UML</link> - User Mode Linux</para>
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<para>Linux Containers (<link xlink:href="http://lxc.sourceforge.net/"
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>LXC</link>). </para>
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</listitem>
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<listitem>
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<para>Quick EMUlator (<link xlink:href="http://wiki.qemu.org/Manual"
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>QEMU</link>).</para>
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</listitem>
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<listitem>
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<para>User Mode Linux (<link
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xlink:href="http://user-mode-linux.sourceforge.net/">UML</link>).</para>
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</listitem>
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<listitem>
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<para><link
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xlink:href="http://www.vmware.com/products/vsphere-hypervisor/support.html"
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>VMWare vSphere</link> 4.1 update 1 and
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newer</para>
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>VMWare vSphere</link>.</para>
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</listitem>
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<listitem>
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<para><link
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xlink:href="http://www.xen.org/support/documentation.html"
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>Xen</link> - Xen, Citrix XenServer and
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Xen Cloud Platform (XCP)</para>
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</listitem>
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<listitem>
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<para><link
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xlink:href="https://wiki.openstack.org/wiki/Baremetal"
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>Bare Metal</link> - Provisions physical
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hardware through pluggable sub-drivers</para>
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<para><link xlink:href="http://www.xen.org/support/documentation.html"
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>Xen</link>.</para>
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</listitem>
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</itemizedlist>
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<para>Please see the <link
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xlink:href="http://docs.openstack.org/trunk/config-reference/content/section_compute-hypervisors.html"
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>Hypervisors</link> section in <citetitle>OpenStack Configuration
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Reference</citetitle> for more information. </para>
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</section>
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<section xml:id="section_users-and-projects">
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<title>Users and tenants</title>
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<para>The OpenStack Compute system is designed to be used
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by many different cloud computing consumers or
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customers, basically tenants on a shared system, using
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role-based access assignments. Roles control the
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actions that a user is allowed to perform.</para><para>In the
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default configuration, most actions do not require a
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particular role, but this is configurable by the
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system administrator editing the appropriate
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<filename>policy.json</filename> file that
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maintains the rules. For example, a rule can be
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defined so that a user cannot allocate a public IP
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without the admin role. A user's access to particular
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images is limited by tenant, but the username and
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password are assigned for each user. Key pairs
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granting access to an instance are enabled for each
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user, but quotas to control resource consumption
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across available hardware resources are for each
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tenant. <note>
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<para>Earlier versions of OpenStack used the term
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"project" instead of "tenant". Because of this
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legacy terminology, some command-line tools
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use <parameter>--project_id</parameter> when a
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tenant ID is expected.</para>
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</note></para>
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<para>While the original EC2 API supports users, OpenStack
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Compute adds the concept of tenants. Tenants are
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isolated resource containers that form the principal
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organizational structure within the Compute service.
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They consist of a separate VLAN, volumes, instances,
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images, keys, and users. A user can specify which
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tenant he or she wishes to be known as by appending
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<literal>:project_id</literal> to his or her
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access key. If no tenant is specified in the API
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request, Compute attempts to use a tenant with the
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same ID as the user.</para>
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<title>Tenants, users, and roles</title>
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<para>The Compute system is designed to be used by many different cloud computing
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consumers or customers, in native terms, tenants on a shared system, using
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role-based access assignments. Roles control the actions that a user is allowed to
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perform.</para>
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<para>While the original EC2 API supports users, Compute uses the concept of tenants.
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Tenants are isolated resource containers that form the principal organizational
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structure within the Compute service. They consist of a separate VLAN, volumes,
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instances, images, keys, and users. A user can specify the tenant by appending
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<literal>:project_id</literal> to their access key. If no tenant is specified in
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the API request, Compute attempts to use a tenant with the same ID as the
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user.</para>
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<para>For tenants, quota controls are available to limit the:<itemizedlist>
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<listitem>
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<para>Number of volumes which may be
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created</para>
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<para>Number of volumes that may be launched.</para>
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</listitem>
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<listitem>
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<para>Total size of all volumes within a
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project as measured in GB</para>
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<para>Number of processor cores and the amount of RAM that may be
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allocated.</para>
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</listitem>
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<listitem>
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<para>Number of instances which may be
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launched</para>
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<para>Floating IP addresses (assigned to any instance when it launches so
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the instance has the same publicly accessible IP addresses).</para>
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</listitem>
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<listitem>
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<para>Number of processor cores which may be
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allocated</para>
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<para>Fixed IP addresses (assigned to the same instance each time it boots,
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publicly or privately accessibletypically private for management
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purposes).</para>
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</listitem>
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<listitem>
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<para>Floating IP addresses (assigned to any
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instance when it launches so the instance
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has the same publicly accessible IP
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addresses)</para>
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</listitem>
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<listitem>
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<para>Fixed IP addresses (assigned to the same
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instance each time it boots, publicly or
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privately accessible, typically private
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for management purposes)</para>
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</listitem>
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</itemizedlist>
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</para>
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</itemizedlist></para><para>Roles control the actions a user is allowed to perform. In the default configuration, most
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actions do not require a particular role, but the system administrator can configure
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them by editing the appropriate <filename>policy.json</filename> file that maintains
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the rules. For example, a rule can be defined so that a user cannot allocate a
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public IP without the admin role. A tenant limits the users' access to particular
|
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images, but each user is assigned the username and password. Key pairs granting
|
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access to an instance are enabled for each user, but quotas are set for each tenant
|
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to control resource consumption across available hardware resources . <note>
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<para>Earlier versions of OpenStack used the term "project" instead of "tenant."
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Because of this legacy terminology, some command-line tools use
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<parameter>--project_id</parameter> when a tenant ID is expected.
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</para>
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</note></para>
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</section>
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<?hard-pagebreak?>
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<section xml:id="section_images-and-instances">
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<title>Images and instances</title>
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<para>This introduction provides a high level overview of
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what images and instances are and description of the
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life-cycle of a typical virtual system within the
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cloud. There are many ways to configure the details of
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an OpenStack cloud and many ways to implement a
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virtual system within that cloud. These configuration
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details as well as the specific command line utilities
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and API calls to perform the actions described are
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presented in <xref linkend="section_image-mgmt"/> and
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the volume-specific info in <link
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xlink:href="http://docs.openstack.org/trunk/config-reference/content/"
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><citetitle> OpenStack Configuration
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Reference</citetitle></link>.</para>
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<para>Images are disk images which are templates for
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virtual machine file systems. The image service,
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Glance, is responsible for the storage and management
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of images within OpenStack.</para>
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<para>Instances are the individual virtual machines
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running on physical compute nodes. The compute
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service, Nova, manages instances. Any number of
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instances maybe started from the same image. Each
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instance is run from a copy of the base image so
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runtime changes made by an instance do not change the
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image it is based on. Snapshots of running instances
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may be taken which create a new image based on the
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current disk state of a particular instance.</para>
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<para>When starting an instance a set of virtual resources
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known as a flavor must be selected. Flavors define how
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many virtual CPUs an instance has and the amount of
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RAM and size of its ephemeral disks. OpenStack
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provides a number of predefined flavors which cloud
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administrators may edit or add to. Users must select
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from the set of available flavors defined on their
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cloud.</para>
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<para>Additional resources such as persistent volume
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storage and public IP address may be added to and
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removed from running instances. The examples below
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show the <systemitem class="service"
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>cinder-volume</systemitem> service which provide
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persistent block storage as opposed to the ephemeral
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storage provided by the instance flavor.</para>
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<para>Here is an example of the life cycle of a typical
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virtual system within an OpenStack cloud to illustrate
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these concepts.</para>
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<para>Images are disk images which are templates for virtual machine file systems. The
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image service, Glance, is responsible for the storage and management of images
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within OpenStack.</para>
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<para>The <link
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xlink:href="http://docs.openstack.org/trunk/config-reference/content/ch_configuring-openstack-image-service.html"
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>Image Services</link> section of <citetitle>OpenStack Configuration
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Reference</citetitle> explains image configuration options, while the <link
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xlink:href="http://docs.openstack.org/user-guide-admin/content/cli_manage_images.html"
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>Manage Images</link> section of <citetitle>OpenStack Admin User
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Guide</citetitle> for specifics about creating and troubleshooting
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images.</para>
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<para>Instances are the individual virtual machines running on physical compute nodes.
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Compute manages instances. Any number of instances may be started from the same
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image. Each instance is run from a copy of the base image so runtime changes made by
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an instance do not change the image it is based on. Snapshots of running instances
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may be taken, creating a new image based on the current disk state of a particular
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instance.</para>
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<para>When starting an instance, a user must select a set of virtual resources known as
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a flavor. Flavors define how many virtual CPUs an instance has and the amount of RAM
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and size of its ephemeral disks. OpenStack provides a number of predefined flavors
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that cloud administrators may edit or add to. Users must select from the set of
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available flavors defined on their cloud. For more information about flavors, see
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the <link xlink:href="http://docs.openstack.org/trunk/openstack-ops/content/flavors.html">Flavors</link> section in <citetitle>OpenStack Operations Guide</citetitle>.</para>
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<para>A user may add and remove additional resources from running instances, such as
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persistent volume storage and public IP address. The following example shows the
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lifecycle of a typical virtual system within an OpenStack cloud. It features the
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<systemitem class="service">cinder-volume</systemitem> service, which provides
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persistent block storage, as opposed to the ephemeral storage provided by the
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instance flavor.</para>
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<simplesect xml:id="initial-instance-state">
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<title>Initial state</title>
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<para>The following diagram shows the system state
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prior to launching an instance. The image store
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fronted by the image service, Glance, has some
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number of predefined images. In the cloud there is
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an available compute node with available vCPU,
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memory and local disk resources. Plus there are a
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number of predefined volumes in the <systemitem
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class="service">cinder-volume</systemitem>
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service.</para>
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<para>The following diagram shows the system state prior to launching an instance.
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The image store fronted by the image service, Glance, has a number of predefined
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images. Inside the cloud, a compute node contains available vCPU, memory, and
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local disk resources. Additionaly, the <systemitem class="service"
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>cinder-volume</systemitem> service provides a number of predefined
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volumes.</para>
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<figure xml:id="initial-instance-state-figure">
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<title>Base image state with no running
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instances</title>
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@ -219,15 +167,12 @@
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</simplesect>
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<simplesect xml:id="running-instance-state">
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<title>Launching an instance</title>
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<para>To launch an instance the user selects an image,
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a flavor and optionally other attributes. In this
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case the selected flavor provides a root volume
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(as all flavors do) labeled vda in the diagram and
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additional ephemeral storage labeled vdb in the
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diagram. The user has also opted to map a volume
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from the <systemitem class="service"
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>cinder-volume</systemitem> store to the third
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virtual disk, vdc, on this instance.</para>
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<para>To launch an instance, the user selects an image, a flavor, and other optional
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attributes. In this case, the selected flavor provides a root volume (as all
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flavors do) labeled vda in the diagram and additional ephemeral storage labeled
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vdb in the diagram. The user has also opted to map a volume from the <systemitem
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class="service">cinder-volume</systemitem> store to the third virtual disk,
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vdc, on this instance.</para>
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<figure xml:id="run-instance-state-figure">
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<title>Instance creation from image and run time
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state</title>
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@ -239,40 +184,27 @@
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</imageobject>
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</mediaobject>
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</figure>
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<para>The OpenStack system copies the base image from
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the image store to the local disk. The local disk
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is the first disk (vda) that the instance
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accesses. Using small images results in faster
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start up of your instances as less data is copied
|
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across the network. The system also creates a new
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empty disk image to present as the second disk
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(vdb). Be aware that the second disk is an empty
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disk with an ephemeral life as it is destroyed
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when you delete the instance. The compute node
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attaches to the requested <systemitem
|
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class="service">cinder-volume</systemitem>
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using iSCSI and maps this to the third disk (vdc)
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as requested. The vCPU and memory resources are
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provisioned and the instance is booted from the
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first drive. The instance runs and changes data on
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the disks indicated in red in the diagram <link
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linkend="run-instance-state-figure"/>.</para>
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<para>The details of this scenario can vary,
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particularly the type of back-end storage and the
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network protocols that are used. One variant worth
|
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mentioning here is that the ephemeral storage used
|
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for volumes vda and vdb in this example may be
|
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backed by network storage rather than local disk.
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The details are left for later chapters.</para>
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<para>The OpenStack system copies the base image from the image store to the local
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disk. The local disk is the first disk (vda) that the instance accesses. Using
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small images results in a faster start up of your instances as less data is
|
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copied across the network. The system also creates a new empty disk image to
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present as the second disk (vdb). Please note that the second disk is an empty
|
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disk with an ephemeral life because it is destroyed when you delete an instance.
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The compute node attaches to the requested <systemitem class="service"
|
||||
>cinder-volume</systemitem> using iSCSI and maps this to the third disk
|
||||
(vdc) as requested. The vCPU and memory resources are provisioned and the
|
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instance is booted from the first drive. The instance runs and changes data on
|
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the disks indicated in red in the diagram.</para>
|
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<para>The details of this scenario can vary, particularly the type of back-end
|
||||
storage and the network protocols that are used. One variant worth mentioning
|
||||
here is that the ephemeral storage used for volumes vda and vdb in this example
|
||||
may be backed by network storage rather than local disk. </para>
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</simplesect>
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<simplesect xml:id="end-instance-state">
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<title>End state</title>
|
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<para>Once the instance has served its purpose and is
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deleted all state is reclaimed, except the
|
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persistent volume. The ephemeral storage is
|
||||
purged. Memory and vCPU resources are released.
|
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And of course the image has remained unchanged
|
||||
through out.</para>
|
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<para>Once the instance has served its purpose and is deleted, all state is
|
||||
reclaimed, except the persistent volume. The ephemeral storage is purged. Memory
|
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and vCPU resources are released. The image remains unchanged throughout.</para>
|
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<figure xml:id="end-instance-state-figure">
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<title>End state of image and volume after
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instance exits</title>
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@ -288,69 +220,47 @@
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</section>
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<section xml:id="section_system-architecture">
|
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<title>System architecture</title>
|
||||
<para>OpenStack Compute consists of several main
|
||||
components. A "cloud controller" contains many of
|
||||
these components, and it represents the global state
|
||||
and interacts with all other components. An API Server
|
||||
acts as the web services front end for the cloud
|
||||
controller. The compute controller provides compute
|
||||
server resources and typically contains the compute
|
||||
service.</para><para>The Object Store component optionally
|
||||
provides storage services. An auth manager provides
|
||||
authentication and authorization services when used
|
||||
with the Compute system, or you can use the Identity
|
||||
Service (keystone) as a separate authentication
|
||||
service. A volume controller provides fast and
|
||||
permanent block-level storage for the compute servers.
|
||||
A network controller provides virtual networks to
|
||||
enable compute servers to interact with each other and
|
||||
with the public network. A scheduler selects the most
|
||||
suitable compute controller to host an
|
||||
instance.</para>
|
||||
<para>OpenStack Compute is built on a shared-nothing,
|
||||
messaging-based architecture. You can run all of the
|
||||
major components on multiple servers including a
|
||||
compute controller, volume controller, network
|
||||
controller, and object store (or image service). A
|
||||
cloud controller communicates with the internal object
|
||||
store through HTTP (Hyper Text Transfer Protocol), but
|
||||
it communicates with a scheduler, network controller,
|
||||
and volume controller through AMQP (Advanced Message
|
||||
Queue Protocol). To avoid blocking each component
|
||||
while waiting for a response, OpenStack Compute uses
|
||||
asynchronous calls, with a call-back that gets
|
||||
triggered when a response is received.</para>
|
||||
<para>To achieve the shared-nothing property with multiple
|
||||
copies of the same component, OpenStack Compute keeps
|
||||
all the cloud system state in a database.</para>
|
||||
<para>Compute consists of several main components. A "cloud controller" contains many of
|
||||
these components, and it represents the global state and interacts with all other
|
||||
components. An API Server acts as the web services front end for the cloud
|
||||
controller. The compute controller provides compute server resources and typically
|
||||
contains the compute service.</para><para>The Object Store component optionally provides storage services. An auth manager provides
|
||||
authentication and authorization services when used with the Compute system, or you
|
||||
can use the Identity Service (Keystone) as a separate authentication service. A
|
||||
volume controller provides fast and permanent block-level storage for the compute
|
||||
servers. A network controller provides virtual networks to enable compute servers to
|
||||
interact with each other and with the public network. A scheduler selects the most
|
||||
suitable compute controller to host an instance.</para>
|
||||
<para>Compute is built on a shared-nothing, messaging-based architecture. You can run
|
||||
all of the major components on multiple servers including a compute controller,
|
||||
volume controller, network controller, and object store (or image service). A cloud
|
||||
controller communicates with the internal object store through Hyper Text Transfer
|
||||
Protocol (HTTP), but it communicates with a scheduler, network controller, and
|
||||
volume controller through Advanced Message Queue Protocol (AMQP). To avoid blocking
|
||||
each component while waiting for a response, Compute uses asynchronous calls, with a
|
||||
callback that gets triggered when a response is received.</para>
|
||||
<para>To achieve the shared-nothing property with multiple copies of the same component,
|
||||
Compute keeps all of the cloud system state in a database.</para>
|
||||
</section>
|
||||
<section xml:id="section_storage-and-openstack-compute">
|
||||
<title>Block Storage and Compute</title>
|
||||
<para>OpenStack provides two classes of block storage,
|
||||
"ephemeral" storage and persistent "volumes".
|
||||
Ephemeral storage exists only for the life of an
|
||||
instance. It persists across reboots of the guest
|
||||
operating system, but when the instance is deleted so
|
||||
is the associated storage. All instances have some
|
||||
ephemeral storage. Volumes are persistent virtualized
|
||||
block devices independent of any particular instance.
|
||||
Volumes may be attached to a single instance at a
|
||||
time, but may be detached or reattached to a different
|
||||
instance while retaining all data, much like a USB
|
||||
drive.</para>
|
||||
<para>OpenStack provides two classes of block storage, ephemeral storage and persistent
|
||||
volumes. Ephemeral storage exists only for the life of an instance. It persists
|
||||
across reboots of the guest operating system, but when the instance is deleted so is
|
||||
the associated storage. All instances have some ephemeral storage. Volumes are
|
||||
persistent virtualized block devices independent of any particular instance. Volumes
|
||||
may be attached to a single instance at a time, but may be detached or reattached to
|
||||
a different instance while retaining all data, much like a USB drive.</para>
|
||||
<simplesect xml:id="section_about-ephemeral-storage">
|
||||
<title>Ephemeral storage</title>
|
||||
<para>Ephemeral storage is associated with a single
|
||||
unique instance. Its size is defined by the flavor
|
||||
of the instance.</para>
|
||||
<para>Data on ephemeral storage ceases to exist when
|
||||
the instance it is associated with is terminated.
|
||||
Rebooting the VM or restarting the host server,
|
||||
however, does not destroy ephemeral data. In the
|
||||
typical use case an instance's root file system is
|
||||
stored on ephemeral storage. This is often an
|
||||
unpleasant surprise for people unfamiliar with the
|
||||
cloud model of computing.</para>
|
||||
<para>Data on ephemeral storage ceases to exist when the instance it is associated
|
||||
with is terminated. Rebooting the VM or restarting the host server, however,
|
||||
does not destroy ephemeral data. In the typical use case, an instance's root
|
||||
file system is stored on ephemeral storage. This is often an unpleasant surprise
|
||||
for people unfamiliar with the cloud model of computing.</para>
|
||||
<para>In addition to the ephemeral root volume, all
|
||||
flavors except the smallest, m1.tiny, provide an
|
||||
additional ephemeral block device whose size
|
||||
@ -380,87 +290,64 @@
|
||||
attached to only one instance at a time, but may
|
||||
be detached and reattached to either the same or
|
||||
different instances.</para>
|
||||
<para>It is possible to configure a volume so that it
|
||||
is bootable and provides a persistent virtual
|
||||
instance similar to traditional non-cloud based
|
||||
virtualization systems. In this use case the
|
||||
resulting instance may still have ephemeral
|
||||
storage depending on the flavor selected, but the
|
||||
root file system (and possibly others) is on the
|
||||
persistent volume and its state is maintained even
|
||||
if the instance it shut down. Details of this
|
||||
configuration are discussed in the <link
|
||||
xlink:href="http://docs.openstack.org/user-guide/content/index.html">
|
||||
<citetitle>OpenStack End User
|
||||
Guide</citetitle></link>.</para>
|
||||
<para>Volumes do not provide concurrent access from
|
||||
multiple instances. For that you need either a
|
||||
traditional network file system like NFS or CIFS
|
||||
or a cluster file system such as GlusterFS. These
|
||||
may be built within an OpenStack cluster or
|
||||
provisioned outside of it, but are not features
|
||||
provided by the OpenStack software.</para>
|
||||
<para>It is possible to configure a volume so that it is bootable and provides a
|
||||
persistent virtual instance similar to traditional non-cloud-based
|
||||
virtualization systems. In this use case, the resulting instance may still have
|
||||
ephemeral storage depending on the flavor selected, but the root file system
|
||||
(and possibly others) is on the persistent volume and its state is maintained
|
||||
even if the instance it shut down. Details of this configuration are discussed
|
||||
in the <citetitle>OpenStack Configuration Reference</citetitle> .</para>
|
||||
<para>Volumes do not provide concurrent access from multiple instances. For that,
|
||||
you need either a traditional network file system like NFS or CIFS or a cluster
|
||||
file system such as GlusterFS. These may be built within an OpenStack cluster or
|
||||
provisioned outside of it, but are not features provided by the OpenStack
|
||||
software.</para>
|
||||
</simplesect>
|
||||
</section>
|
||||
</section>
|
||||
<section xml:id="section_image-mgmt">
|
||||
<title>Image management</title>
|
||||
<para>The OpenStack Image Service, code-named <emphasis
|
||||
role="italic">glance</emphasis>, discovers, registers,
|
||||
and retrieves virtual machine images. The service includes
|
||||
a <link
|
||||
xlink:href="http://api.openstack.org/api-ref.html#os-images-2.0"
|
||||
>RESTful API</link> that allows users to query VM
|
||||
image metadata and retrieve the actual image with HTTP
|
||||
<para>The Image service, code-named Glance, discovers,
|
||||
registers, and retrieves virtual machine images. The service includes a <link
|
||||
xlink:href="http://api.openstack.org/api-ref.html#os-images-2.0">RESTful API</link>
|
||||
that allows users to query VM image metadata and retrieve the actual image with HTTP
|
||||
requests. You can also use the <link
|
||||
xlink:href="http://docs.openstack.org/user-guide/content/cli_manage_images.html"
|
||||
>glance command-line tool</link>, or the <link
|
||||
xlink:href="http://docs.openstack.org/developer/python-glanceclient/"
|
||||
>Python API</link> to accomplish the same
|
||||
tasks.</para>
|
||||
<para>VM images made available through OpenStack Image Service
|
||||
can be stored in a variety of locations. The OpenStack
|
||||
Image Service supports the following back end
|
||||
stores:</para>
|
||||
xlink:href="http://docs.openstack.org/developer/python-glanceclient/">Python
|
||||
API</link> to accomplish the same tasks.</para>
|
||||
<para>VM images made available through the Image service can be stored in a variety of
|
||||
locations. The Image service supports the following back-end stores:</para>
|
||||
<itemizedlist>
|
||||
<listitem>
|
||||
<para>OpenStack Object Storage - OpenStack Object
|
||||
Storage (code-named <emphasis role="italic"
|
||||
>swift</emphasis>) is the highly-available
|
||||
object storage project in OpenStack.</para>
|
||||
<para>Object Storage service (code-named Swift)The highly-available object storage
|
||||
project in OpenStack.</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>File system - The default back end that
|
||||
OpenStack Image Service uses to store virtual
|
||||
machine images is the file system back end. This
|
||||
simple back end writes image files to the local
|
||||
file system.</para>
|
||||
<para>File systemThe default back-end that OpenStack Image Service uses to store
|
||||
virtual machine images is the file system back-end. This simple back-end writes
|
||||
image files to the local file system.</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>S3 - This back end allows OpenStack Image
|
||||
Service to store virtual machine images in
|
||||
Amazon’s S3 service.</para>
|
||||
<para>S3This back-end allows OpenStack Image Service to store virtual machine
|
||||
images in Amazon’s S3 service.</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>HTTP - OpenStack Image Service can read virtual
|
||||
machine images that are available through HTTP
|
||||
somewhere on the Internet. This store is read
|
||||
<para>HTTPOpenStack Image Service can read virtual machine images that are
|
||||
available through HTTP somewhere on the Internet. This store is read
|
||||
only.</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>Rados Block Device (RBD) - This back end stores
|
||||
images inside of a Ceph storage cluster using
|
||||
Ceph's RBD interface.</para>
|
||||
<para>Rados Block Device (RBD)This back-end stores images inside of a Ceph storage
|
||||
cluster using Ceph's RBD interface.</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>GridFS - This back end stores images inside of
|
||||
MongoDB.</para>
|
||||
<para>GridFSThis back-end stores images inside of MongoDB.</para>
|
||||
</listitem>
|
||||
</itemizedlist>
|
||||
<para>You must have a working installation of the Image
|
||||
Service, with a working endpoint and users created in the
|
||||
Identity Service. Also, you must source the environment
|
||||
variables required by the nova and glance clients.</para>
|
||||
<para>You must have a working installation of the Image Service, with a working endpoint and
|
||||
users created in the Identity Service. Also, you must source the environment variables
|
||||
required by the Compute and Image clients.</para>
|
||||
</section>
|
||||
<section xml:id="section_instance-mgmt">
|
||||
<title>Instance management</title>
|
||||
@ -487,18 +374,15 @@
|
||||
installer:
|
||||
<programlisting language="bash">sudo pip install python-novaclient</programlisting>
|
||||
</para>
|
||||
<para>Full details for <application>nova</application>
|
||||
and other CLI tools are provided in the <link
|
||||
xlink:href="http://docs.openstack.org/user-guide/content/index.html"
|
||||
><citetitle>OpenStack End User Guide</citetitle></link>. What follows is
|
||||
the minimal introduction required to follow the
|
||||
CLI example in this chapter. In the case of a
|
||||
conflict the
|
||||
<link
|
||||
<para>Full details for <application>nova</application> and other CLI tools are
|
||||
provided in <link
|
||||
xlink:href="http://docs.openstack.org/user-guide/content/index.html"
|
||||
><citetitle>OpenStack End User Guide</citetitle></link> should be
|
||||
considered authoritative (and a bug filed against
|
||||
this section).</para>
|
||||
><citetitle>OpenStack End User Guide</citetitle></link>. What follows is
|
||||
the minimal introduction required to follow the CLI example in this chapter. In
|
||||
the case of a conflict in <link
|
||||
xlink:href="http://docs.openstack.org/user-guide/content/index.html"
|
||||
><citetitle>OpenStack End User Guide</citetitle></link> should be
|
||||
considered authoritative (and a bug filed against this section).</para>
|
||||
<para>To function, the
|
||||
<application>nova</application> CLI needs the following information:</para>
|
||||
<itemizedlist>
|
||||
@ -561,15 +445,11 @@ export OS_TENANT_NAME=demoproject</programlisting>
|
||||
</simplesect>
|
||||
<simplesect xml:id="instance-mgmt-novaapi">
|
||||
<title>Compute API</title>
|
||||
<para>OpenStack provides a RESTful API for all
|
||||
functionality. Complete API documentation is
|
||||
available at <link
|
||||
xlink:href="http://docs.openstack.org/api"
|
||||
>http://docs.openstack.org/api</link>. The
|
||||
<link
|
||||
xlink:href="http://docs.openstack.org/api/openstack-compute/2"
|
||||
>OpenStack Compute API</link> documentation
|
||||
refers to instances as "servers".</para>
|
||||
<para>OpenStack provides a RESTful API for all functionality. Complete API
|
||||
documentation is available at <link xlink:href="http://docs.openstack.org/api"
|
||||
>http://docs.openstack.org/api</link>. The <link
|
||||
xlink:href="http://docs.openstack.org/api/openstack-compute/2">OpenStack
|
||||
Compute API</link> documentation refers to instances as "servers."</para>
|
||||
<para>The <link linkend="instance-mgmt-novaclient"
|
||||
>nova cli</link> can be made to show the API
|
||||
calls it is making by passing it the
|
||||
@ -1580,13 +1460,11 @@ net.bridge.bridge-nf-call-ip6tables=0</programlisting>
|
||||
</section>
|
||||
<section xml:id="section_compute-system-admin">
|
||||
<title>System administration</title>
|
||||
<para>By understanding how the different installed nodes
|
||||
interact with each other you can administer the Compute
|
||||
installation. Compute offers many ways to install using
|
||||
multiple servers but the general idea is that you can have
|
||||
multiple compute nodes that control the virtual servers
|
||||
and a cloud controller node that contains the remaining
|
||||
Nova services.</para>
|
||||
<para>By understanding how the different installed nodes interact with each other you can
|
||||
administer the Compute installation. Compute offers many ways to install using multiple
|
||||
servers but the general idea is that you can have multiple compute nodes that control
|
||||
the virtual servers and a cloud controller node that contains the remaining Compute
|
||||
services.</para>
|
||||
<para>The Compute cloud works through the interaction of a
|
||||
series of daemon processes named nova-* that reside
|
||||
persistently on the host machine or machines. These
|
||||
@ -1761,8 +1639,7 @@ net.bridge.bridge-nf-call-ip6tables=0</programlisting>
|
||||
signed with the secret key. Upon receipt of API
|
||||
requests, Compute verifies the signature and runs
|
||||
commands on behalf of the user.</para>
|
||||
<para>To begin using nova, you must create a user with the
|
||||
Identity Service.</para>
|
||||
<para>To begin using Compute, you must create a user with the Identity Service.</para>
|
||||
</section>
|
||||
<section xml:id="section_manage-the-cloud">
|
||||
<title>Manage the cloud</title>
|
||||
@ -1919,15 +1796,12 @@ qualname = nova</programlisting></para>
|
||||
</simplesect>
|
||||
<simplesect>
|
||||
<title>Syslog</title>
|
||||
<para>You can configure OpenStack Compute services to
|
||||
send logging information to syslog. This is useful
|
||||
if you want to use rsyslog, which forwards the
|
||||
logs to a remote machine. You need to separately
|
||||
configure the Compute service (nova), the Identity
|
||||
service (keystone), the Image service (glance),
|
||||
and, if you are using it, the Block Storage
|
||||
service (cinder) to send log messages to syslog.
|
||||
To do so, add the following lines to:</para>
|
||||
<para>You can configure OpenStack Compute services to send logging information to
|
||||
syslog. This is useful if you want to use rsyslog, which forwards the logs to a
|
||||
remote machine. You need to separately configure the Compute service (Nova), the
|
||||
Identity service (Keystone), the Image service (Glance), and, if you are using
|
||||
it, the Block Storage service (Cinder) to send log messages to syslog. To do so,
|
||||
add the following lines to:</para>
|
||||
<itemizedlist>
|
||||
<listitem>
|
||||
<para><filename>/etc/nova/nova.conf</filename></para>
|
||||
@ -2198,37 +2072,26 @@ HostC p2 5 10240 150
|
||||
<programlisting>UPDATE instances SET host = 'np-rcc46' WHERE uuid = '3f57699a-e773-4650-a443-b4b37eed5a06'; </programlisting>
|
||||
</step>
|
||||
<step>
|
||||
<para>Next, if using a hypervisor that relies
|
||||
on libvirt (such as KVM) it is a good idea
|
||||
to update the
|
||||
<literal>libvirt.xml</literal> file
|
||||
(found in
|
||||
<literal>/var/lib/nova/instances/[instance
|
||||
ID]</literal>). The important changes
|
||||
to make are to change the
|
||||
<literal>DHCPSERVER</literal> value to
|
||||
the host ip address of the nova compute
|
||||
host that is the VMs new home, and update
|
||||
the VNC IP if it isn't already
|
||||
<literal>0.0.0.0</literal>.</para>
|
||||
<para>Next, if using a hypervisor that relies on libvirt (such as KVM) it is
|
||||
a good idea to update the <literal>libvirt.xml</literal> file (found in
|
||||
<literal>/var/lib/nova/instances/[instance ID]</literal>). The
|
||||
important changes to make are to change the
|
||||
<literal>DHCPSERVER</literal> value to the host ip address of the
|
||||
Compute host that is the VMs new home, and update the VNC IP if it isn't
|
||||
already <literal>0.0.0.0</literal>.</para>
|
||||
</step>
|
||||
<step>
|
||||
<para>Next, reboot the VM:</para>
|
||||
<screen><prompt>$</prompt> <userinput>nova reboot --hard 3f57699a-e773-4650-a443-b4b37eed5a06</userinput></screen>
|
||||
</step>
|
||||
<step>
|
||||
<para>In theory, the above database update and
|
||||
<literal>nova reboot</literal> command
|
||||
are all that is required to recover the
|
||||
VMs from a failed host. However, if
|
||||
further problems occur, consider looking
|
||||
at recreating the network filter
|
||||
configuration using
|
||||
<literal>virsh</literal>, restarting
|
||||
the nova services or updating the
|
||||
<literal>vm_state</literal> and
|
||||
<literal>power_state</literal> in the
|
||||
nova database.</para>
|
||||
<para>In theory, the above database update and <literal>nova
|
||||
reboot</literal> command are all that is required to recover the VMs
|
||||
from a failed host. However, if further problems occur, consider looking
|
||||
at recreating the network filter configuration using
|
||||
<literal>virsh</literal>, restarting the Compute services or
|
||||
updating the <literal>vm_state</literal> and
|
||||
<literal>power_state</literal> in the Compute database.</para>
|
||||
</step>
|
||||
</procedure>
|
||||
</section>
|
||||
@ -2301,9 +2164,7 @@ find / -gid 120 -exec chgrp nova {} \;</programlisting>
|
||||
</procedure>
|
||||
</section>
|
||||
<section xml:id="section_nova-disaster-recovery-process">
|
||||
<title>Nova disaster recovery process</title>
|
||||
<para>Sometimes, things just don't go right. An incident
|
||||
is never planned, by its definition.</para>
|
||||
<title>Compute disaster recovery process</title>
|
||||
<para>In this section describes how to manage your cloud
|
||||
after a disaster, and how to easily back up the
|
||||
persistent storage volumes. Back ups ARE mandatory,
|
||||
@ -2313,8 +2174,7 @@ find / -gid 120 -exec chgrp nova {} \;</programlisting>
|
||||
xlink:href="http://en.wikipedia.org/wiki/Disaster_Recovery_Plan"
|
||||
>http://en.wikipedia.org/wiki/Disaster_Recovery_Plan</link>.</para>
|
||||
<simplesect>
|
||||
<title>A- The disaster Recovery Process
|
||||
presentation</title>
|
||||
<title>A- The disaster recovery process presentation</title>
|
||||
<para>A disaster could happen to several components of
|
||||
your architecture: a disk crash, a network loss, a
|
||||
power cut, and so on. In this example, assume the
|
||||
@ -2399,9 +2259,8 @@ find / -gid 120 -exec chgrp nova {} \;</programlisting>
|
||||
are no longer running)</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para>Into the database, data was not updated
|
||||
at all, since nova could not have guessed
|
||||
the crash.</para>
|
||||
<para>Into the database, data was not updated at all, since Compute could
|
||||
not have guessed the crash.</para>
|
||||
</listitem>
|
||||
</itemizedlist>
|
||||
<para>Before going further, and to prevent the admin
|
||||
@ -2446,89 +2305,62 @@ find / -gid 120 -exec chgrp nova {} \;</programlisting>
|
||||
</para>
|
||||
</simplesect>
|
||||
<simplesect>
|
||||
<title>B - The Disaster Recovery Process
|
||||
itself</title>
|
||||
<title>B - The disaster recovery procedure</title>
|
||||
<para><itemizedlist>
|
||||
<listitem>
|
||||
<para><emphasis role="bold"> Instance to
|
||||
Volume relation </emphasis>
|
||||
<para><emphasis role="bold"> Instance-to-volume relation </emphasis>
|
||||
</para>
|
||||
<para>We need to get the current relation
|
||||
from a volume to its instance, because
|
||||
we recreate the attachment:</para>
|
||||
<para>This relation could be figured by
|
||||
running <command>nova
|
||||
volume-list</command> (note that
|
||||
nova client includes ability to get
|
||||
volume info from cinder)</para>
|
||||
<para>We need to get the current relation from a volume to its instance,
|
||||
because we recreate the attachment:</para>
|
||||
<para>This relation could be figured by running <command>nova
|
||||
volume-list</command> (note that nova client includes ability to
|
||||
get volume info from cinder)</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para><emphasis role="bold"> Database
|
||||
Update </emphasis>
|
||||
<para><emphasis role="bold"> Update the database </emphasis>
|
||||
</para>
|
||||
<para>Second, we need to update the
|
||||
database in order to clean the stalled
|
||||
state. Now that we have saved the
|
||||
attachments we need to restore for
|
||||
every volume, the database can be
|
||||
cleaned with the following queries:
|
||||
<para>Second, we need to update the database in order to clean the
|
||||
stalled state. Now that we have saved the attachments we need to
|
||||
restore for every volume, the database can be cleaned with the
|
||||
following queries:
|
||||
<programlisting><prompt>mysql></prompt> <userinput>use cinder;</userinput>
|
||||
<prompt>mysql></prompt> <userinput>update volumes set mountpoint=NULL;</userinput>
|
||||
<prompt>mysql></prompt> <userinput>update volumes set status="available" where status <>"error_deleting";</userinput>
|
||||
<prompt>mysql></prompt> <userinput>update volumes set attach_status="detached";</userinput>
|
||||
<prompt>mysql></prompt> <userinput>update volumes set instance_id=0;</userinput> </programlisting>Now,
|
||||
when running <command>nova
|
||||
volume-list</command> all volumes
|
||||
should be available.</para>
|
||||
when running <command>nova volume-list</command> all volumes should
|
||||
be available.</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para><emphasis role="bold"> Instances
|
||||
Restart </emphasis>
|
||||
<para><emphasis role="bold"> Restart nstances </emphasis>
|
||||
</para>
|
||||
<para>We need to restart the instances.
|
||||
This can be done through a simple
|
||||
<command>nova reboot
|
||||
<replaceable>$instance</replaceable></command>
|
||||
<para>You can restart the instances through a simple <command>nova
|
||||
reboot <replaceable>$instance</replaceable></command>
|
||||
</para>
|
||||
<para>At that stage, depending on your
|
||||
image, some instances completely
|
||||
reboot and become reachable, while
|
||||
others stop on the "plymouth"
|
||||
<para>At that stage, depending on your image, some instances completely
|
||||
reboot and become reachable, while others stop on the "plymouth"
|
||||
stage.</para>
|
||||
<para><emphasis role="bold">DO NOT reboot
|
||||
a second time</emphasis> the ones
|
||||
which are stopped at that stage
|
||||
(<emphasis role="italic">see below,
|
||||
the fourth step</emphasis>). In
|
||||
fact it depends on whether or not you
|
||||
added an
|
||||
<filename>/etc/fstab</filename>
|
||||
entry for that volume. Images built
|
||||
with the <emphasis role="italic"
|
||||
>cloud-init</emphasis> package
|
||||
remain in a pending state, while
|
||||
others skip the missing volume and
|
||||
start. (More information is available
|
||||
on <link
|
||||
xlink:href="https://help.ubuntu.com/community/CloudInit"
|
||||
>help.ubuntu.com</link>.) The idea
|
||||
of that stage is only to ask nova to
|
||||
reboot every instance, so the stored
|
||||
state is preserved.</para>
|
||||
<para><emphasis role="bold">DO NOT reboot a second time</emphasis> the
|
||||
ones which are stopped at that stage (<emphasis role="italic">see
|
||||
below, the fourth step</emphasis>). In fact it depends on
|
||||
whether or not you added an <filename>/etc/fstab</filename> entry
|
||||
for that volume. Images built with the <emphasis role="italic"
|
||||
>cloud-init</emphasis> package remain in a pending state, while
|
||||
others skip the missing volume and start. (More information is
|
||||
available on <link
|
||||
xlink:href="https://help.ubuntu.com/community/CloudInit"
|
||||
>help.ubuntu.com</link>.) The idea of that stage is only to ask
|
||||
nova to reboot every instance, so the stored state is
|
||||
preserved.</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para><emphasis role="bold"> Volume
|
||||
Attachment </emphasis>
|
||||
<para><emphasis role="bold"> Reattach volumes</emphasis>
|
||||
</para>
|
||||
<para>After the restart, we can reattach
|
||||
the volumes to their respective
|
||||
instances. Now that nova has restored
|
||||
the right status, it is time to
|
||||
perform the attachments through a
|
||||
<command>nova
|
||||
volume-attach</command></para>
|
||||
<para>Here is a simple snippet that uses
|
||||
the file we created:</para>
|
||||
<para>After the restart, we can reattach the volumes to their respective
|
||||
instances. Now that nova has restored the right status, it is time
|
||||
to perform the attachments through a <command>nova
|
||||
volume-attach</command></para>
|
||||
<para>Here is a simple snippet that uses the file we created:</para>
|
||||
<programlisting language="bash">#!/bin/bash
|
||||
|
||||
while read line; do
|
||||
@ -2539,30 +2371,22 @@ while read line; do
|
||||
nova volume-attach $instance $volume $mount_point
|
||||
sleep 2
|
||||
done < $volumes_tmp_file</programlisting>
|
||||
<para>At that stage, instances that were
|
||||
pending on the boot sequence
|
||||
(<emphasis role="italic"
|
||||
>plymouth</emphasis>) automatically
|
||||
continue their boot, and restart
|
||||
normally, while the ones that booted
|
||||
see the volume.</para>
|
||||
<para>At that stage, instances that were pending on the boot sequence
|
||||
(<emphasis role="italic">plymouth</emphasis>) automatically
|
||||
continue their boot, and restart normally, while the ones that
|
||||
booted see the volume.</para>
|
||||
</listitem>
|
||||
<listitem>
|
||||
<para><emphasis role="bold"> SSH into
|
||||
instances </emphasis>
|
||||
<para><emphasis role="bold"> SSH into instances </emphasis>
|
||||
</para>
|
||||
<para>If some services depend on the
|
||||
volume, or if a volume has an entry
|
||||
into fstab, it could be good to simply
|
||||
restart the instance. This restart
|
||||
needs to be made from the instance
|
||||
itself, not through nova. So, we SSH
|
||||
into the instance and perform a
|
||||
reboot:</para>
|
||||
<para>If some services depend on the volume, or if a volume has an entry
|
||||
into fstab, it could be good to simply restart the instance. This
|
||||
restart needs to be made from the instance itself, not through nova.
|
||||
So, we SSH into the instance and perform a reboot:</para>
|
||||
<screen><prompt>#</prompt> <userinput>shutdown -r now</userinput></screen>
|
||||
</listitem>
|
||||
</itemizedlist>Voila! You successfully recovered
|
||||
your cloud after that.</para>
|
||||
</itemizedlist>By completing this procedure, you will have successfully
|
||||
recovered your cloud.</para>
|
||||
<para>Here are some suggestions:</para>
|
||||
<para><itemizedlist>
|
||||
<listitem>
|
||||
@ -2619,7 +2443,7 @@ done < $volumes_tmp_file</programlisting>
|
||||
</para>
|
||||
</simplesect>
|
||||
<simplesect>
|
||||
<title>C- Scripted DRP</title>
|
||||
<title>C- scripted DRP</title>
|
||||
<para>You can download from <link
|
||||
xlink:href="https://github.com/Razique/BashStuff/blob/master/SYSTEMS/OpenStack/SCR_5006_V00_NUAC-OPENSTACK-DRP-OpenStack.sh"
|
||||
>here</link> a bash script which performs
|
||||
|
||||
@ -5,37 +5,30 @@
|
||||
xmlns:xlink="http://www.w3.org/1999/xlink"
|
||||
version="5.0">
|
||||
<title>Secure with root wrappers</title>
|
||||
<para>The goal of the root wrapper is to allow the nova
|
||||
unprivileged user to run a number of actions as the root user,
|
||||
in the safest manner possible. Historically, Nova used a
|
||||
specific sudoers file listing every command that the nova user
|
||||
was allowed to run, and just used sudo to run that command as
|
||||
root. However this was difficult to maintain (the sudoers file
|
||||
was in packaging), and did not allow for complex filtering of
|
||||
parameters (advanced filters). The rootwrap was designed to
|
||||
solve those issues.</para>
|
||||
<para>The goal of the root wrapper is to allow the Compute unprivileged user to run a number of
|
||||
actions as the root user, in the safest manner possible. Historically, Compute used a
|
||||
specific sudoers file listing every command that the Compute user was allowed to run, and
|
||||
just used sudo to run that command as root. However this was difficult to maintain (the
|
||||
sudoers file was in packaging), and did not allow for complex filtering of parameters
|
||||
(advanced filters). The rootwrap was designed to solve those issues.</para>
|
||||
<simplesect> <title>How rootwrap works</title>
|
||||
<para>Instead of just calling sudo make me a sandwich, Compute services starting with nova- call
|
||||
sudo nova-rootwrap /etc/nova/rootwrap.conf make me a sandwich.
|
||||
A generic sudoers entry lets the nova user run nova-rootwrap
|
||||
as root. The nova-rootwrap code looks for filter definition directories
|
||||
in its configuration file, and loads command filters from
|
||||
them. Then it checks if the command requested by Compute matches
|
||||
one of those filters, in which case it executes the command
|
||||
(as root). If no filter matches, it denies the request.</para></simplesect>
|
||||
sudo nova-rootwrap /etc/nova/rootwrap.conf make me a sandwich. A generic sudoers entry
|
||||
lets the Compute user run nova-rootwrap as root. The nova-rootwrap code looks for filter
|
||||
definition directories in its configuration file, and loads command filters from them.
|
||||
Then it checks if the command requested by Compute matches one of those filters, in
|
||||
which case it executes the command (as root). If no filter matches, it denies the
|
||||
request.</para></simplesect>
|
||||
<simplesect>
|
||||
<title>Security model</title>
|
||||
<para>The escalation path is fully controlled by the root
|
||||
user. A sudoers entry (owned by root) allows nova to run
|
||||
(as root) a specific rootwrap executable, and only with a
|
||||
specific configuration file (which should be owned by
|
||||
root). nova-rootwrap imports the Python modules it needs
|
||||
from a cleaned (and system-default) PYTHONPATH. The
|
||||
configuration file (also root-owned) points to root-owned
|
||||
filter definition directories, which contain root-owned
|
||||
filters definition files. This chain ensures that the nova
|
||||
user itself is not in control of the configuration or
|
||||
modules used by the nova-rootwrap executable.</para>
|
||||
<para>The escalation path is fully controlled by the root user. A sudoers entry (owned by
|
||||
root) allows Compute to run (as root) a specific rootwrap executable, and only with a
|
||||
specific configuration file (which should be owned by root). nova-rootwrap imports the
|
||||
Python modules it needs from a cleaned (and system-default) PYTHONPATH. The
|
||||
configuration file (also root-owned) points to root-owned filter definition directories,
|
||||
which contain root-owned filters definition files. This chain ensures that the Compute
|
||||
user itself is not in control of the configuration or modules used by the nova-rootwrap
|
||||
executable.</para>
|
||||
</simplesect>
|
||||
<simplesect>
|
||||
<title>Details of rootwrap.conf</title>
|
||||
|
||||
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|
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|
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|
Before Width: | Height: | Size: 31 KiB After Width: | Height: | Size: 30 KiB |
@ -1,10 +1,10 @@
|
||||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<section xmlns="http://docbook.org/ns/docbook"
|
||||
xmlns:xi="http://www.w3.org/2001/XInclude"
|
||||
xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:id="section-troubleshooting-openstack-compute">
|
||||
<title>Troubleshooting OpenStack Compute</title>
|
||||
xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:id="section_compute-troubleshooting">
|
||||
<title>Troubleshooting Compute</title>
|
||||
<para>Common problems for Compute typically involve misconfigured networking or credentials that are not sourced properly in the environment. Also, most flat networking configurations do not enable ping or ssh from a compute node to the instances running on that node. Another common problem is trying to run 32-bit images on a 64-bit compute node. This section offers more information about how to troubleshoot Compute.</para>
|
||||
<section xml:id="log-files-for-openstack-compute"><title>Log files for OpenStack Compute</title>
|
||||
<section xml:id="log-files-for-openstack-compute"><title>Log files for Compute</title>
|
||||
|
||||
<para>Compute stores a log file for each service in
|
||||
<filename>/var/log/nova</filename>. For example,
|
||||
@ -34,8 +34,8 @@
|
||||
daemon logs to syslog.</para>
|
||||
</section>
|
||||
|
||||
<section xml:id="common-errors-and-fixes-for-openstack-compute">
|
||||
<title>Common Errors and Fixes for OpenStack Compute</title>
|
||||
<section xml:id="section_compute-common-errors-and-fixes">
|
||||
<title>Common errors and fixes for Compute</title>
|
||||
<para>The ask.openstack.org site offers a place to ask and
|
||||
answer questions, and you can also mark questions as
|
||||
frequently asked questions. This section describes some
|
||||
@ -43,7 +43,8 @@
|
||||
are constantly fixing bugs, so online resources are a
|
||||
great way to get the most up-to-date errors and
|
||||
fixes.</para>
|
||||
<para>Credential errors, 401, 403 forbidden errors</para>
|
||||
<section xml:id="section_credential-errors">
|
||||
<title>Credential errors, 401, 403 forbidden errors</title>
|
||||
<para>A 403 forbidden error is caused by missing credentials.
|
||||
Through current installation methods, there are basically
|
||||
two ways to get the <filename>novarc</filename> file. The manual method
|
||||
@ -63,7 +64,9 @@
|
||||
<para>You may also need to check your http proxy settings to see if
|
||||
they are causing problems with the <filename>novarc</filename>
|
||||
creation.</para>
|
||||
<para>Instance errors</para>
|
||||
</section>
|
||||
<section xml:id="section_instance-errors">
|
||||
<title>Instance errors</title>
|
||||
<para>Sometimes a particular instance shows "pending" or you
|
||||
cannot SSH to it. Sometimes the image itself is the
|
||||
problem. For example, when using flat manager networking,
|
||||
@ -109,11 +112,11 @@
|
||||
<filename>/var/log/libvirt/qemu</filename>
|
||||
to see if it exists and has any useful error messages
|
||||
in it.</para>
|
||||
|
||||
<para>Finally, from the directory for the instance under
|
||||
<filename>/var/lib/nova/instances</filename>, try
|
||||
<screen><prompt>#</prompt> <userinput>virsh create libvirt.xml</userinput></screen> and see if you
|
||||
get an error when running this.</para>
|
||||
</section>
|
||||
</section>
|
||||
<section xml:id="reset-state">
|
||||
<title>Manually reset the state of an instance</title>
|
||||
@ -129,7 +132,7 @@
|
||||
example:<screen><prompt>$</prompt> <userinput>nova reset-state --active c6bbbf26-b40a-47e7-8d5c-eb17bf65c485</userinput> </screen></para>
|
||||
</section>
|
||||
<section xml:id="problems-with-injection">
|
||||
<title>Problems with Injection</title>
|
||||
<title>Problems with injection</title>
|
||||
<para>If you are diagnosing problems with instances not booting,
|
||||
or booting slowly, consider investigating file injection as a
|
||||
cause. Setting <literal>libvirt_injection_partition</literal>
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user