openstack-manuals/doc/admin-guide-cloud/compute/section_compute-system-admin.xml
Tom Fifield 4b9fe08d94 Updates for Kilo release
Many small updates to various sections to:
* remove/reword/redirect old pre-icehouse cruft
* update links from Juno to kilo (eg config reference)
* generally improve anything that looked dated

Change-Id: I26618be8527cccc1cbb7811272613da7d410fe50
2015-04-29 19:32:41 +08:00

570 lines
32 KiB
XML

<?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_compute-system-admin">
<title>System administration</title>
<para>To effectively administer Compute, you must understand how the
different installed nodes interact with each other. Compute can be
installed in many different ways using multiple servers, but generally
multiple compute nodes control the virtual servers and a cloud
controller node contains the remaining Compute services.</para>
<para>The Compute cloud works using a series of daemon processes named
<systemitem>nova-*</systemitem> that exist persistently on the host
machine. These binaries can all run on the same machine or be spread out
on multiple boxes in a large deployment. The responsibilities of
services and drivers are:</para>
<itemizedlist>
<title>Services</title>
<listitem>
<para><systemitem class="service">nova-api</systemitem>: receives
XML requests and sends them to the rest of the system. A WSGI app
routes and authenticates requests. Supports the EC2 and
OpenStack APIs. A <filename>nova.conf</filename> configuration
file is created when Compute is installed.</para>
</listitem>
<listitem>
<para><systemitem>nova-cert</systemitem>: manages certificates.</para>
</listitem>
<listitem>
<para><systemitem class="service">nova-compute</systemitem>: manages
virtual machines. Loads a Service object, and exposes the public
methods on ComputeManager through a Remote Procedure Call (RPC).</para>
</listitem>
<listitem>
<para><systemitem>nova-conductor</systemitem>: provides
database-access support for Compute nodes (thereby reducing
security risks).</para>
</listitem>
<listitem>
<para><systemitem>nova-consoleauth</systemitem>: manages console
authentication.</para>
</listitem>
<listitem>
<para><systemitem class="service">nova-objectstore</systemitem>: a
simple file-based storage system for images that replicates most
of the S3 API. It can be replaced with OpenStack Image service and
either a simple image manager or OpenStack Object Storage as the
virtual machine image storage facility. It must exist on the same
node as <systemitem class="service">nova-compute</systemitem>.</para>
</listitem>
<listitem>
<para><systemitem class="service">nova-network</systemitem>: manages
floating and fixed IPs, DHCP, bridging and VLANs. Loads a Service
object which exposes the public methods on one of the subclasses
of <systemitem class="service">NetworkManager</systemitem>.
Different networking strategies are available by changing the
<literal>network_manager</literal> configuration option to
<literal>FlatManager</literal>,
<literal>FlatDHCPManager</literal>, or
<literal>VLANManager</literal> (defaults to
<literal>VLANManager</literal> if nothing is specified).</para>
</listitem>
<listitem>
<para><systemitem>nova-scheduler</systemitem>: dispatches requests
for new virtual machines to the correct node.</para>
</listitem>
<listitem>
<para><systemitem>nova-novncproxy</systemitem>: provides a VNC proxy
for browsers, allowing VNC consoles to access virtual machines.</para>
</listitem>
</itemizedlist>
<note><para>Some services have drivers that change how the service
implements its core functionality. For example, the
<systemitem>nova-compute</systemitem> service supports drivers that
let you choose which hypervisor type it can use.
<systemitem>nova-network</systemitem> and
<systemitem>nova-scheduler</systemitem> also have drivers.</para>
</note>
<section xml:id="section_manage-compute-users">
<title>Manage Compute users</title>
<para>Access to the Euca2ools (ec2) API is controlled by an access key and
a secret key. The user's access key needs to be included in the request,
and the request must be 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 Compute, you must create a user with the Identity
Service.</para>
</section>
<xi:include href="../../common/section_cli_nova_volumes.xml"/>
<xi:include href="../../common/section_cli_nova_customize_flavors.xml"/>
<xi:include href="section_compute_config-firewalls.xml"/>
<section xml:id="admin-password-injection">
<title>Injecting the administrator password</title>
<para>Compute can generate a random administrator (root) password and
inject that password into an instance. If this feature is enabled, users
can <command>ssh</command> to an instance without an <command>ssh</command>
keypair. The random password appears in the output of the
<command>nova boot</command> command. You can also view and set the
admin password from the dashboard.</para>
<simplesect>
<title>Password injection using the dashboard</title>
<para>By default, the dashboard will display the <literal>admin</literal>
password and allow the user to modify it.</para>
<para>If you do not want to support password injection, disable the
password fields by editing the dashboard's
<filename>local_settings</filename> file. On Fedora/RHEL/CentOS, the
file location is <filename>/etc/openstack-dashboard/local_settings</filename>.
On Ubuntu and Debian, it is <filename>/etc/openstack-dashboard/local_settings.py</filename>.
On openSUSE and SUSE Linux Enterprise Server, it is
<filename>/srv/www/openstack-dashboard/openstack_dashboard/local/local_settings.py</filename></para>
<programlisting language="ini">OPENSTACK_HYPERVISOR_FEATURE = {
...
'can_set_password': False,
}</programlisting>
</simplesect>
<simplesect>
<title>Password injection on libvirt-based hypervisors</title>
<para>For hypervisors that use the libvirt backend (such as KVM, QEMU,
and LXC), admin password injection is disabled by default. To enable
it, set this option in <filename>/etc/nova/nova.conf</filename>:</para>
<programlisting language="ini">[libvirt]
inject_password=true</programlisting>
<para>When enabled, Compute will modify the password of the admin
account by editing the <filename>/etc/shadow</filename> file inside
the virtual machine instance.</para>
<note>
<para>Users can only <command>ssh</command> to the instance by using
the admin password if the virtual machine image is a Linux
distribution, and it has been configured to allow users to
<command>ssh</command> as the root user. This is not the case for
<link xlink:href="http://cloud-images.ubuntu.com/">Ubuntu cloud
images</link> which, by default, do not allow users to
<command>ssh</command> to the root account.</para>
</note>
</simplesect>
<simplesect>
<title>Password injection and XenAPI (XenServer/XCP)</title>
<para>when using the XenAPI hypervisor backend, Compute uses the XenAPI
agent to inject passwords into guests. The virtual machine image must
be configured with the agent for password injection to work.</para>
</simplesect>
<simplesect>
<title>Password injection and Windows images (all hypervisors)</title>
<para>For Windows virtual machines, configure the Windows image to
retrieve the admin password on boot by installing an agent such as
<link xlink:href="https://github.com/cloudbase/cloudbase-init">
cloudbase-init</link>.</para>
</simplesect>
</section>
<section xml:id="section_manage-the-cloud">
<title>Manage the cloud</title>
<para>System administrators can use <command>nova</command> client and
<command>Euca2ools</command> commands to manage their clouds.</para>
<para><command>nova</command> client and <command>euca2ools</command> can
be used by all users, though specific commands might be restricted by
Role Based Access Control in the Identity Service.</para>
<procedure>
<title>Managing the cloud with nova client</title>
<step>
<para>The <package>python-novaclient</package> package provides a
<code>nova</code> shell that enables Compute API interactions from
the command line. Install the client, and provide your user name and
password (which can be set as environment variables for convenience),
for the ability to administer the cloud from the command line.</para>
<para>To install <package>python-novaclient</package>, download the
tarball from <link xlink:href="http://pypi.python.org/pypi/python-novaclient/#downloads">
http://pypi.python.org/pypi/python-novaclient/#downloads</link> and
then install it in your favorite Python environment.</para>
<screen><prompt>$</prompt> <userinput>curl -O http://pypi.python.org/packages/source/p/python-novaclient/python-novaclient-2.6.3.tar.gz</userinput>
<prompt>$</prompt> <userinput>tar -zxvf python-novaclient-2.6.3.tar.gz</userinput>
<prompt>$</prompt> <userinput>cd python-novaclient-2.6.3</userinput></screen>
<para>As root, run:</para>
<screen><prompt>#</prompt> <userinput>python setup.py install</userinput></screen>
</step>
<step>
<para>Confirm the installation was successful:</para>
<screen><prompt>$</prompt> <userinput>nova help</userinput>
<computeroutput>usage: nova [--version] [--debug] [--os-cache] [--timings]
[--timeout <replaceable>SECONDS</replaceable>] [--os-username <replaceable>AUTH_USER_NAME</replaceable>]
[--os-password <replaceable>AUTH_PASSWORD</replaceable>]
[--os-tenant-name <replaceable>AUTH_TENANT_NAME</replaceable>]
[--os-tenant-id <replaceable>AUTH_TENANT_ID</replaceable>] [--os-auth-url <replaceable>AUTH_URL</replaceable>]
[--os-region-name <replaceable>REGION_NAME</replaceable>] [--os-auth-system <replaceable>AUTH_SYSTEM</replaceable>]
[--service-type <replaceable>SERVICE_TYPE</replaceable>] [--service-name <replaceable>SERVICE_NAME</replaceable>]
[--volume-service-name <replaceable>VOLUME_SERVICE_NAME</replaceable>]
[--endpoint-type <replaceable>ENDPOINT_TYPE</replaceable>]
[--os-compute-api-version <replaceable>COMPUTE_API_VERSION</replaceable>]
[--os-cacert <replaceable>CA_CERTIFICATE</replaceable>] [--insecure]
[--bypass-url <replaceable>BYPASS_URL</replaceable>]
<replaceable>SUBCOMMAND</replaceable> ...</computeroutput></screen>
<para>This command returns a list of <command>nova</command> commands
and parameters. To get help for a subcommand, run:</para>
<screen><prompt>$</prompt> <userinput>nova help <replaceable>SUBCOMMAND</replaceable></userinput></screen>
<para>For a complete list of <command>nova</command> commands and
parameters, see the <link xlink:href="http://docs.openstack.org/cli-reference/content/">
<citetitle>OpenStack Command-Line Reference</citetitle></link>.</para>
</step>
<step>
<para>Set the required parameters as environment variables to make
running commands easier. For example, you can add
<parameter>--os-username</parameter> as a <command>nova</command>
option, or set it as an environment variable. To set the user name,
password, and tenant as environment variables, use:</para>
<screen><prompt>$</prompt> <userinput>export OS_USERNAME=joecool</userinput>
<prompt>$</prompt> <userinput>export OS_PASSWORD=coolword</userinput>
<prompt>$</prompt> <userinput>export OS_TENANT_NAME=coolu</userinput> </screen>
</step>
<step>
<para>The Identity Service will give you an authentication endpoint,
which Compute recognizes as <literal>OS_AUTH_URL</literal>.</para>
<screen><prompt>$</prompt> <userinput>export OS_AUTH_URL=http://hostname:5000/v2.0</userinput>
<prompt>$</prompt> <userinput>export NOVA_VERSION=1.1</userinput></screen>
</step>
</procedure>
<section xml:id="section_euca2ools">
<title>Managing the cloud with euca2ools</title>
<para>The <command>euca2ools</command> command-line tool provides a
command line interface to EC2 API calls. For more information about
<command>euca2ools</command>, see
<link xlink:href="http://open.eucalyptus.com/wiki/Euca2oolsGuide_v1.3">
http://open.eucalyptus.com/wiki/Euca2oolsGuide_v1.3</link></para>
</section>
<xi:include href="../../common/section_cli_nova_usage_statistics.xml"/>
</section>
<section xml:id="section_manage-logs">
<title>Logging</title>
<simplesect>
<title>Logging module</title>
<para>Logging behavior can be changed by creating a configuration file.
To specify the configuration file, add this line to the
<filename>/etc/nova/nova.conf</filename> file:</para>
<programlisting language="ini">log-config=/etc/nova/logging.conf</programlisting>
<para>
To change the logging level, add <literal>DEBUG</literal>,
<literal>INFO</literal>, <literal>WARNING</literal>, or
<literal>ERROR</literal> as a parameter.
</para>
<para>The logging configuration file is an INI-style configuration
file, which must contain a section called
<literal>logger_nova</literal>. This controls the behavior of
the logging facility in the <literal>nova-*</literal> services. For
example:</para>
<programlisting language="ini">[logger_nova]
level = INFO
handlers = stderr
qualname = nova</programlisting>
<para>This example sets the debugging level to <literal>INFO</literal>
(which is less verbose than the default <literal>DEBUG</literal>
setting).</para>
<para>For more about the logging configuration syntax, including the
<literal>handlers</literal> and <literal>quaname</literal>
variables, see the
<link xlink:href="http://docs.python.org/release/2.7/library/logging.html#configuration-file-format">
Python documentation</link> on logging configuration files.</para>
<para>For an example <filename>logging.conf</filename> file with
various defined handlers, see the
<link xlink:href="http://docs.openstack.org/kilo/config-reference/content/">
<citetitle>OpenStack Configuration Reference</citetitle></link>.
</para>
</simplesect>
<simplesect>
<title>Syslog</title>
<para>OpenStack Compute services can send logging information to
<systemitem>syslog</systemitem>. This is useful if you want to use
<systemitem>rsyslog</systemitem> to forward logs to a remote machine.
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
<systemitem>syslog</systemitem>. Open these configuration files:</para>
<itemizedlist>
<listitem>
<para><filename>/etc/nova/nova.conf</filename></para>
</listitem>
<listitem>
<para><filename>/etc/keystone/keystone.conf</filename></para>
</listitem>
<listitem>
<para><filename>/etc/glance/glance-api.conf</filename></para>
</listitem>
<listitem>
<para><filename>/etc/glance/glance-registry.conf</filename></para>
</listitem>
<listitem>
<para><filename>/etc/cinder/cinder.conf</filename></para>
</listitem>
</itemizedlist>
<para>In each configuration file, add these lines:</para>
<programlisting language="ini">verbose = False
debug = False
use_syslog = True
syslog_log_facility = LOG_LOCAL0</programlisting>
<para>In addition to enabling <systemitem>syslog</systemitem>, these
settings also turn off verbose and debugging output from the log.</para>
<note>
<para>Although this example uses the same local facility for each
service (<literal>LOG_LOCAL0</literal>, which corresponds to
<systemitem>syslog</systemitem> facility <literal>LOCAL0</literal>),
we recommend that you configure a separate local facility for each
service, as this provides better isolation and more flexibility.
For example, you can capture logging information at different
severity levels for different services.
<systemitem>syslog</systemitem> allows you to define up to eight
local facilities, <literal>LOCAL0, LOCAL1, ..., LOCAL7</literal>.
For more information, see the <systemitem>syslog</systemitem>
documentation.</para>
</note>
</simplesect>
<simplesect>
<title>Rsyslog</title>
<para><systemitem>rsyslog</systemitem> is useful for setting up a
centralized log server across multiple machines. This section
briefly describe the configuration to set up an
<systemitem>rsyslog</systemitem> server. A full treatment of
<systemitem>rsyslog</systemitem> is beyond the scope of this book.
This section assumes <systemitem>rsyslog</systemitem> has already
been installed on your hosts (it is installed by default on most
Linux distributions).</para>
<para>This example provides a minimal configuration for
<filename>/etc/rsyslog.conf</filename> on the log server host,
which receives the log files:</para>
<programlisting># provides TCP syslog reception
$ModLoad imtcp
$InputTCPServerRun 1024</programlisting>
<para>Add a filter rule to <filename>/etc/rsyslog.conf</filename>
which looks for a host name. This example uses
<replaceable>COMPUTE_01</replaceable> as the compute host name:</para>
<programlisting>:hostname, isequal, "<replaceable>COMPUTE_01</replaceable>" /mnt/rsyslog/logs/compute-01.log</programlisting>
<para>On each compute host, create a file named
<filename>/etc/rsyslog.d/60-nova.conf</filename>, with the
following content:</para>
<programlisting># prevent debug from dnsmasq with the daemon.none parameter
*.*;auth,authpriv.none,daemon.none,local0.none -/var/log/syslog
# Specify a log level of ERROR
local0.error @@172.20.1.43:1024</programlisting>
<para>Once you have created the file, restart the
<systemitem>rsyslog</systemitem> service. Error-level log messages
on the compute hosts should now be sent to the log server.</para>
</simplesect>
<simplesect>
<title>Serial console</title>
<para>The serial console provides a way to examine kernel output and
other system messages during troubleshooting if the instance lacks
network connectivity.</para>
<para>OpenStack Icehouse and earlier supports read-only access using
the serial console using the <command>os-GetSerialOutput</command>
server action. Most cloud images enable this feature by default.
For more information, see <link linkend="section_compute-empty-log-output">
Troubleshoot Compute</link>.</para>
<para>OpenStack Juno and later supports read-write access using the
serial console using the <command>os-GetSerialConsole</command>
server action. This feature also requires a websocket client to
access the serial console.</para>
<procedure>
<title>Configuring read-write serial console access</title>
<para>On a compute node, edit the
<filename>/etc/nova/nova.conf</filename> file:</para>
<step>
<para>In the <literal>[serial_console]</literal> section,
enable the serial console:</para>
<programlisting language="ini">[serial_console]
...
enabled = true</programlisting>
</step>
<step>
<para>In the <literal>[serial_console]</literal> section,
configure the serial console proxy similar to graphical
console proxies:</para>
<programlisting language="ini">[serial_console]
...
base_url = ws://<replaceable>controller</replaceable>:6083/
listen = 0.0.0.0
proxyclient_address = <replaceable>MANAGEMENT_INTERFACE_IP_ADDRESS</replaceable></programlisting>
<para>The <option>base_url</option> option specifies the base
URL that clients receive from the API upon requesting a serial
console. Typically, this refers to the host name of the
controller node.</para>
<para>The <option>listen</option> option specifies the network
interface <systemitem class="service">nova-compute</systemitem>
should listen on for virtual console connections. Typically,
0.0.0.0 will enable listening on all interfaces.</para>
<para>The <option>proxyclient_address</option> option specifies
which network interface the proxy should connect to. Typically,
this refers to the IP address of the management interface.</para>
</step>
</procedure>
<para>When you enable read-write serial console access, Compute
will add serial console information to the Libvirt XML file for
the instance. For example:</para>
<programlisting language="xml">&lt;console type='tcp'>
&lt;source mode='bind' host='127.0.0.1' service='10000'/>
&lt;protocol type='raw'/>
&lt;target type='serial' port='0'/>
&lt;alias name='serial0'/>
&lt;/console></programlisting>
<procedure>
<title>Accessing the serial console on an instance</title>
<step>
<para>Use the <command>nova get-serial-proxy</command> command
to retrieve the websocket URL for the serial console on the
instance:</para>
<screen><prompt>$</prompt> <userinput>nova get-serial-proxy <replaceable>INSTANCE_NAME</replaceable></userinput>
<computeroutput>+--------+-----------------------------------------------------------------+
| Type | Url |
+--------+-----------------------------------------------------------------+
| serial | ws://127.0.0.1:6083/?token=18510769-71ad-4e5a-8348-4218b5613b3d |
+--------+-----------------------------------------------------------------+</computeroutput></screen>
<para>Alternatively, use the API directly:</para>
<screen><prompt>$</prompt> <userinput>curl -i 'http://&lt;controller&gt;:8774/v2/&lt;tenant_uuid>/servers/&lt;instance_uuid>/action' \
-X POST \
-H "Accept: application/json" \
-H "Content-Type: application/json" \
-H "X-Auth-Project-Id: &lt;project_id>" \
-H "X-Auth-Token: &lt;auth_token>" \
-d '{"os-getSerialConsole": {"type": "serial"}}'</userinput></screen>
</step>
<step>
<para>Use Python websocket with the URL to generate
<literal>.send</literal>, <literal>.recv</literal>, and
<literal>.fileno</literal> methods for serial console access.
For example:</para>
<programlisting language="python">import websocket
ws = websocket.create_connection(
'ws://127.0.0.1:6083/?token=18510769-71ad-4e5a-8348-4218b5613b3d',
subprotocols=['binary', 'base64'])</programlisting>
<para>Alternatively, use a Python websocket client such as
<link xlink:href="https://github.com/larsks/novaconsole/"/>.</para>
</step>
</procedure>
<note>
<para>When you enable the serial console, typical instance logging
using the <command>nova console-log</command> command is disabled.
Kernel output and other system messages will not be visible
unless you are actively viewing the serial console.</para>
</note>
</simplesect>
</section>
<xi:include href="section_compute-rootwrap.xml"/>
<xi:include href="section_compute-configure-migrations.xml"/>
<section xml:id="section_live-migration-usage">
<title>Migrate instances</title>
<para>This section discusses how to migrate running instances from one
OpenStack Compute server to another OpenStack Compute server.</para>
<para>Before starting a migration, review the
<link linkend="section_configuring-compute-migrations">Configure
migrations section</link>.</para>
<note>
<para>Although the <command>nova</command> command is called
<command>live-migration</command>, under the default Compute
configuration options, the instances are suspended before migration.
For more information, see <link xlink:href="http://docs.openstack.org/kilo/config-reference/content/list-of-compute-config-options.html">
Configure migrations</link> in the <citetitle>OpenStack
Configuration Reference</citetitle>.</para>
</note>
<procedure>
<title>Migrating instances</title>
<step>
<para>Check the ID of the instance to be migrated:</para>
<screen><prompt>$</prompt> <userinput>nova list</userinput>
<computeroutput><![CDATA[+--------------------------------------+------+--------+-----------------+
| ID | Name | Status |Networks |
+--------------------------------------+------+--------+-----------------+
| d1df1b5a-70c4-4fed-98b7-423362f2c47c | vm1 | ACTIVE | private=a.b.c.d |
| d693db9e-a7cf-45ef-a7c9-b3ecb5f22645 | vm2 | ACTIVE | private=e.f.g.h |
+--------------------------------------+------+--------+-----------------+]]></computeroutput></screen>
</step>
<step>
<para>Check the information associated with the instance. In this
example, <literal>vm1</literal> is running on
<literal>HostB</literal>:</para>
<screen><prompt>$</prompt> <userinput>nova show d1df1b5a-70c4-4fed-98b7-423362f2c47c</userinput>
<computeroutput><![CDATA[+-------------------------------------+----------------------------------------------------------+
| Property | Value |
+-------------------------------------+----------------------------------------------------------+
...
| OS-EXT-SRV-ATTR:host | HostB |
...
| flavor | m1.tiny |
| id | d1df1b5a-70c4-4fed-98b7-423362f2c47c |
| name | vm1 |
| private network | a.b.c.d |
| status | ACTIVE |
...
+-------------------------------------+----------------------------------------------------------+]]></computeroutput></screen>
</step>
<step>
<para>Select the compute node the instance will be migrated to. In
this example, we will migrate the instance to
<literal>HostC</literal>, because
<systemitem class="service">nova-compute</systemitem> is running
on it.:</para>
<screen><prompt>#</prompt> <userinput>nova service-list</userinput>
<computeroutput>+------------------+------------+----------+---------+-------+----------------------------+-----------------+
| Binary | Host | Zone | Status | State | Updated_at | Disabled Reason |
+------------------+------------+----------+---------+-------+----------------------------+-----------------+
| nova-consoleauth | HostA | internal | enabled | up | 2014-03-25T10:33:25.000000 | - |
| nova-scheduler | HostA | internal | enabled | up | 2014-03-25T10:33:25.000000 | - |
| nova-conductor | HostA | internal | enabled | up | 2014-03-25T10:33:27.000000 | - |
| nova-compute | HostB | nova | enabled | up | 2014-03-25T10:33:31.000000 | - |
| nova-compute | HostC | nova | enabled | up | 2014-03-25T10:33:31.000000 | - |
| nova-cert | HostA | internal | enabled | up | 2014-03-25T10:33:31.000000 | - |
+------------------+------------+----------+---------+-------+----------------------------+-----------------+</computeroutput></screen>
</step>
<step>
<para>Check that <literal>HostC</literal> has enough resources for
migration:</para>
<screen><prompt>#</prompt> <userinput>nova host-describe HostC</userinput>
<computeroutput>+-----------+------------+-----+-----------+---------+
| HOST | PROJECT | cpu | memory_mb | disk_gb |
+-----------+------------+-----+-----------+---------+
| HostC | (total) | 16 | 32232 | 878 |
| HostC | (used_now) | 13 | 21284 | 442 |
| HostC | (used_max) | 13 | 21284 | 442 |
| HostC | p1 | 13 | 21284 | 442 |
| HostC | p2 | 13 | 21284 | 442 |
+-----------+------------+-----+-----------+---------+</computeroutput></screen>
<itemizedlist>
<listitem>
<para><literal>cpu</literal>: Number of CPUs</para>
</listitem>
<listitem>
<para><literal>memory_mb</literal>: Total amount of memory,
in MB</para>
</listitem>
<listitem>
<para><literal>disk_gb</literal>: Total amount of space for
NOVA-INST-DIR/instances, in GB</para>
</listitem>
</itemizedlist>
<para>In this table, the first row shows the total amount of
resources available on the physical server. The second line shows
the currently used resources. The third line shows the maximum
used resources. The fourth line and below shows the resources
available for each project.</para>
</step>
<step>
<para>Migrate the instances using the
<command>nova live-migration</command> command:</para>
<screen><prompt>$</prompt> <userinput>nova live-migration <replaceable>SERVER</replaceable> <replaceable>HOST_NAME</replaceable></userinput></screen>
<para>In this example, <replaceable>SERVER</replaceable> can be the
ID or name of the instance. Another example:</para>
<screen><prompt>$</prompt> <userinput>nova live-migration d1df1b5a-70c4-4fed-98b7-423362f2c47c HostC</userinput><computeroutput>
<![CDATA[Migration of d1df1b5a-70c4-4fed-98b7-423362f2c47c initiated.]]></computeroutput></screen>
</step>
<step>
<para>Check the instances have been migrated successfully, using
<command>nova list</command>. If instances are still running on
<literal>HostB</literal>, check the log files at src/dest for
<systemitem class="service">nova-compute</systemitem> and
<systemitem class="service">nova-scheduler</systemitem>) to
determine why.</para>
</step>
</procedure>
</section>
<xi:include href="../../common/section_compute-configure-console.xml"/>
<xi:include href="section_compute-configure-service-groups.xml"/>
<xi:include href="section_compute-security.xml"/>
<xi:include href="section_compute-recover-nodes.xml"/>
</section>