openstack-manuals/doc/admin-guide-cloud/ch_blockstorage.xml
Diane Fleming 371f556463 Heading and other consistency/clarity edits - Cloud Admin Guide
Closes-Bug: #1250515

author: diane fleming

Change-Id: Ib1755a3e10ddd348d0575b3c5e6aa1660d5f612e
backport: none
2013-11-22 11:13:21 -06:00

145 lines
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XML

<?xml version="1.0" encoding="UTF-8"?>
<chapter 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="managing-volumes">
<?dbhtml stop-chunking?>
<title>Block Storage</title>
<para>The OpenStack Block Storage service works though the
interaction of a series of daemon processes named <systemitem
class="daemon">cinder-*</systemitem> that reside
persistently on the host machine or machines. The binaries can
all be run from a single node, or spread across multiple
nodes. They can also be run on the same node as other
OpenStack services.</para>
<section xml:id="section_block-storage-intro">
<title>Introduction to Block Storage</title>
<para>To administer the OpenStack Block Storage service, it is
helpful to understand a number of concepts. You must make
certain choices when you configure the Block Storage
service in OpenStack. The bulk of the options come down to
two choices, single node or multi-node install. You can
read a longer discussion about storage decisions in <link
xlink:href="http://docs.openstack.org/trunk/openstack-ops/content/storage_decision.html"
>Storage Decisions</link> in the <citetitle>OpenStack
Operations Guide</citetitle>.</para>
<para>The OpenStack Block Storage Service enables you to add
extra block-level storage to your OpenStack Compute
instances. This service is similar to the Amazon EC2
Elastic Block Storage (EBS) offering.</para>
</section>
<?hard-pagebreak?>
<section xml:id="section_manage-volumes">
<title>Manage volumes</title>
<para>The default OpenStack Block Storage service
implementation is an iSCSI solution that uses Logical
Volume Manager (LVM) for Linux.</para>
<note>
<para>The OpenStack Block Storage service is not a shared
storage solution like a Storage Area Network (SAN) of
NFS volumes, where you can attach a volume to multiple
servers. With the OpenStack Block Storage service, you
can attach a volume to only one instance at a
time.</para>
<para>The OpenStack Block Storage service also provides
drivers that enable you to use several vendors'
back-end storage devices, in addition to or instead of
the base LVM implementation.</para>
</note>
<para>This high-level procedure shows you how to create and
attach a volume to a server instance.</para>
<procedure>
<step>
<para>You must configure both OpenStack Compute and
the OpenStack Block Storage service through the
<filename>cinder.conf</filename> file.</para>
</step>
<step>
<para>Create a volume through the <command>cinder
create</command> command. This command creates
an LV into the volume group (VG)
"cinder-volumes."</para>
</step>
<step>
<para>Attach the volume to an instance through the
<command>nova volume-attach</command> command.
This command creates a unique iSCSI IQN that is
exposed to the compute node.</para>
<substeps>
<step>
<para>The compute node, which runs the
instance, now has an active ISCSI session
and new local storage (usually a
<filename>/dev/sdX</filename>
disk).</para>
</step>
<step>
<para>libvirt uses that local storage as
storage for the instance. The instance get
a new disk, usually a
<filename>/dev/vdX</filename>
disk.</para>
</step>
</substeps>
</step>
</procedure>
<para>For this particular walk through, one cloud controller
runs <systemitem class="service">nova-api</systemitem>,
<systemitem class="service"
>nova-scheduler</systemitem>, <systemitem
class="service">nova-objectstore</systemitem>,
<literal>nova-network</literal> and
<literal>cinder-*</literal> services. Two additional
compute nodes run <systemitem class="service"
>nova-compute</systemitem>. The walk through uses a
custom partitioning scheme that carves out 60 GB of space
and labels it as LVM. The network uses the
<literal>FlatManager</literal> and
<literal>NetworkManager</literal> settings for
OpenStack Compute (Nova).</para>
<para>The network mode does not interfere with the way cinder
works, but you must set up networking for cinder to work.
For details, see <xref linkend="ch_networking"/>.</para>
<para>To set up Compute to use volumes, ensure that Block
Storage is installed along with lvm2. This guide describes
how to troubleshoot your installation and back up your
Compute volumes.</para>
<section xml:id="boot-from-volume">
<title>Boot from volume</title>
<para>In some cases, instances can be stored and run from
inside volumes. For information, see the <link
xlink:href="http://docs.openstack.org/user-guide/content/boot_from_volume.html"
>Launch an instance from a volume</link> section
in the <link
xlink:href="http://docs.openstack.org/user-guide/content/"
><citetitle>OpenStack End User
Guide</citetitle></link>.</para>
</section>
<?hard-pagebreak?>
<xi:include href="section_multi_backend.xml"/>
<xi:include href="section_backup-block-storage-disks.xml"/>
<xi:include href="section_volume-migration.xml"/>
</section>
<section xml:id="troubleshooting-cinder-install">
<title>Troubleshoot your installation</title>
<para>This section provides useful tips to help troubleshoot
your Block Storage Service installation.</para>
<xi:include href="section_ts_cinder_config.xml"/>
<xi:include href="section_ts_multipath_warn.xml"/>
<xi:include href="section_ts_vol_attach_miss_sg_scan.xml"/>
<xi:include
href="section_ts_HTTP_bad_req_in_cinder_vol_log.xml"/>
<xi:include href="section_ts_attach_vol_fail_not_JSON.xml"/>
<xi:include href="section_ts_duplicate_3par_host.xml"/>
<xi:include
href="section_ts_failed_attach_vol_after_detach.xml"/>
<xi:include
href="section_ts_failed_attach_vol_no_sysfsutils.xml"/>
<xi:include href="section_ts_failed_connect_vol_FC_SAN.xml"/>
<xi:include href="section_ts_failed_sched_create_vol.xml"/>
<xi:include href="section_ts_no_emulator_x86_64.xml"/>
<xi:include href="section_ts_non_existent_host.xml"/>
<xi:include href="section_ts_non_existent_vlun.xml"/>
</section>
</chapter>