Starting with Ganeti 2.2, instances can be moved between separate Ganeti clusters using a new tool, move-instance. The tool has a number of features:
The design of the inter-cluster instances moves is described in detail in the Ganeti 2.2 design document. The instance move tool talks to the Ganeti clusters via RAPI and can run on any machine which can connect to the cluster’s RAPI. Despite their similar name, the instance move tool should not be confused with the gnt-instance move command, which is used to move without changes (instead of export/import plus rename) an instance within the cluster.
To prevent third parties from accessing the instance data, all data exchanged between the clusters is signed using a secret key, the “cluster domain secret”. It is recommended to assign the same domain secret to all clusters of the same security domain, so that instances can be easily moved between them. By checking the signatures, the destination cluster can be sure the third party (e.g. this tool) didn’t modify the received crypto keys and connection information.
To create a new, random cluster domain secret, run the following command on the master node:
$ gnt-cluster renew-crypto --new-cluster-domain-secret
To read and set the cluster domain secret from the contents of a file, run the following command on the master node:
$ gnt-cluster renew-crypto --cluster-domain-secret=/.../ganeti.cds
More information about the renew-crypto command can be found in gnt-cluster(8).
As soon as the clusters share a cluster domain secret, instances can be moved. The tool usage is as follows:
$ move-instance [options] source-cluster destination-cluster instance-name...
Multiple instances can be moved with one invocation of the instance move tool, though a few options are only available when moving a single instance.
The most important options are listed below. Unless specified otherwise, destination-related options default to the source value (e.g. setting --src-rapi-port=1234 will make --dest-rapi-port‘s default 1234).
The exit value of the tool is zero if and only if all instance moves were successful.
If using certificates signed by a CA, then you need to pass the same CA certificate via both --src-ca-file and dest-ca-file.
However, if you’re using self-signed certificates, this has a few (security) implications:
It is therefore recommended to copy only the certificate from the rapi.pem files, and pass these to --src-ca-file and --dest-ca-file appropriately.