This change moves the .rst files into the main adming-guide-cloud folder now conversion is complete. changes to the project config and to the openstack manuals to stop sync of .xml files are also needed. Change-Id: I498e8d6ac3cb80da413e23b14a0959abd58e7d79 Implements: blueprint reorganise-user-guides
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Migrate instances
This section discusses how to migrate running instances from one OpenStack Compute server to another OpenStack Compute server.
Before starting a migration, review the Configure migrations section.
Note
Although the
nova
command is calledlive-migration
, under the default Compute configuration options, the instances are suspended before migration. For more information, see Configure migrations. in the OpenStack Configuration Reference.
Migrating instances
Check the ID of the instance to be migrated:
$ nova list
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 Check the information associated with the instance. In this example,
vm1
is running onHostB
:$ nova show d1df1b5a-70c4-4fed-98b7-423362f2c47c
Property Value ...
OS-EXT-SRV-ATTR:host
...
flavor
id
name
private network
status
...
...
HostB
...
m1.tiny
d1df1b5a-70c4-4fed-98b7-423362f2c47c
vm1
a.b.c.d
ACTIVE
...
Select the compute node the instance will be migrated to. In this example, we will migrate the instance to
HostC
, because nova-compute is running on it:nova service-list 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 Check that
HostC
has enough resources for migration:# nova host-describe HostC
HOST PROJECT cpu memory_mb disk_bg HostC HostC HostC HostC HostC (total) (used_now) (used_max) p1 p2 32232 21284 21284 21284 21284 878 442 422 422 422 cpu
: Number of CPUsmemory_mb
: Total amount of memory, in MBdisk_gb
: Total amount of space for NOVA-INST-DIR/instances, in GB
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.
Migrate the instance using the
nova live-migration
command:$ nova live-migration SERVER HOST_NAME
In this example, SERVER can be the ID or name of the instance. Another example:
$ nova live-migration d1df1b5a-70c4-4fed-98b7-423362f2c47c HostC Migration of d1df1b5a-70c4-4fed-98b7-423362f2c47c initiated.
Warning
When using live migration to move workloads between Icehouse and Juno compute nodes, it may cause data loss because libvirt live migration with shared block storage was buggy (potential loss of data) before version 3.32. This issue can be solved when we upgrade to RPC API version 4.0.
Check that the instance has been migrated successfully, using
nova list
. If the instance is still running onHostB
, check the log files atsrc/dest
for nova-compute and nova-scheduler to determine why.