In order to ensure optimal system performance, or to perform
system maintenance, it is sometimes necessary to move running
instances between Node Controllers (NCs). You can migrate
instances individually, or migrate all instances from a given
NC.
Important: For migrations to succeed, you must have
INSTANCE_PATH set to the same value in the
eucalyptus.conf file on each NC.
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To migrate a single instance to another NC, enter the
following command:
euserv-migrate-instances -i INSTANCE_ID
You can also optionally specify --include-dest HOST_NC_IP
or --exclude-dest HOST_NC_IP, to ensure that the
instance is migrated to one of the specified NCs, or to avoid migrating the
instance to any of the specified NCs. These flags may be used more than once
to specify multiple NCs.
-
To migrate all instances away from an NC, enter the following command:
euserv-migrate-instances --source HOST_NC_IP
You can also optionally specify euserv-modify-service -s stop HOST_NC_IP, to stop the
specified NC and ensure that no new instances are started on that NC while
the migration occurs. This allows you to safely remove the NC without
interrupting running instances. The NC will remain in the DISABLED state
until it is explicitly enabled using euserv-modify-service -s start HOST_NC_IP.
In some cases, timeouts may cause a migration to initially
fail. Run the command again to complete the migration.
If the migration fails, check the
nc.log file on the source and
destination NCs. If you see an error similar to:
libvirt: Cannot get interface MTU on 'br0': No such device (code=38)
... then ensure the NCs have the same interface and bridge device names, as described in
Configure Bridges.