12.2.2. Configure live migration for heavy workloads

Procedure

1. Edit the HyperConverged CR and add the necessary parameters for migrating heavy workloads:

   $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv

   Example configuration file:

   apiVersion: hco.kubevirt.io/v1beta1
   kind: HyperConverged
   metadata:
     name: kubevirt-hyperconverged
     namespace: openshift-cnv
   spec:
     liveMigrationConfig:
       bandwidthPerMigration: 0Mi
       completionTimeoutPerGiB: 150
       parallelMigrationsPerCluster: 5
       parallelOutboundMigrationsPerNode: 1
       progressTimeout: 150
       allowPostCopy: true

   where:

   bandwidthPerMigration

   Specifies the bandwidth of each migration in bytes per second. The default is 0, which is unlimited.

   completionTimeoutPerGiB

   Specifies the length of time, in seconds per GiB of memory, at which the migration is canceled if it has not completed and post copy mode is triggered, if enabled. You can lower completionTimeoutPerGiB to trigger post copy mode earlier in the migration process, or raise the completionTimeoutPerGiB to trigger post copy mode later in the migration process.

   parallelMigrationsPerCluster

   Specifies the number of migrations running in parallel in the cluster. The default is 5. Keeping the parallelMigrationsPerCluster setting low is better when migrating heavy workloads.

   parallelOutboundMigrationsPerNode

   Specifies the maximum number of outbound migrations per node. Configure a single VM per node for heavy workloads.

   progressTimeout

   Specifies the length of time, in seconds, at which the migration is canceled if memory copy fails to make progress. Increase this parameter for large memory sizes running heavy workloads.

   allowPostCopy

   Specifies whether the post copy mode is enabled. You can enable post copy mode to allow the migration of one node to another to converge, even if a VM is running a heavy workload and the memory dirty rate is too high. Set allowPostCopy to true to enable post copy mode.

2. Optional: If your main network is too busy for the migration, configure a secondary, dedicated migration network.

   참고

   Post copy mode can impact performance during the transfer, and should not be used for critical data, or with unstable networks.