Installation guide

live (default) — the virtual machine continues to run while most of its memory contents are copied
to the destination host. This minimizes the inaccessibility of the VM (typically well under 1 second)
at the expense of performance of the VM during the migration and total amount of time it takes for
the migration to complete.
pause - the virtual machine is frozen in memory while its memory contents are copied to the
destination host. This minimizes the amount of time it takes for a virtual machine migration to
complete.
Which migration style you use is dependent on availability and performance requirements. For
example, a live migration may mean 29 seconds of degraded performance and 1 second of complete
unavailability while a pause migration may mean 8 seconds of complete unavailability and no
otherwise degraded performance.
Important
A virtual machine may be a component of service, but doing this disables all forms of
migration and most of the below convenience features.
Additionally, the use of migration with KVM requires careful configuration of ssh.
3.5.3. RGManager Virt ual Machine Feat ures
The following section lists the various ways RGManager eases use of managing virtual machines.
3.5.3.1 . Virt ual Machine T racking
Starting a virtual machine with cl usvcad m if the VM is already running will cause rgmanager to
search the cluster for the VM and mark the VM as started wherever it is found.
Administrators who accidentally migrate a VM between cluster nodes with non-cluster tools such as
vi rsh will cause rgmanager to search the cluster for the VM and mark the VM as started wherever it
is found.
Note
If the VM is running in multiple locations, RGManager does not warn you.
3.5.3.2 . T ransie nt Do m ain Suppo rt
Rgmanager supports transient virtual machines which are supported by libvirt. This enables
rgmanager to create and remove virtual machines on the fly, helping reduce the possibility of
accidental double-starts of virtual machines due to the use of non-cluster tools.
Support of transient virtual machines also enables you to store libvirt XML description files on a
clustered file system so that you do not have to manually keep /etc/li bvi rt/q emu in sync across
the cluster.
3.5.3.2.1. Man ag emen t Feat u res
⁠Chapt er 3. RG Manager
19