#Updating with RevisionBased strategy

The RevisionBased strategy runs two revisions of the control plane during an upgrade. This approach supports gradual workload migration from the old control plane to the new one, enabling canary upgrades. It also supports upgrades across more than one minor version.

The RevisionBased strategy creates a new Istio control plane instance for each change to the spec.version field. The existing control plane remains active until all workloads transition to the new instance. You can move the workloads to the new control plane by updating the istio.io/rev labels or using the IstioRevisionTag resource, followed by a restart.

Although the RevisionBased strategy involves additional steps and requires multiple control plane instances to run concurrently during the upgrade, it allows for gradual migration of workloads. This approach enables validation of the updated control plane with a subset of workloads before migrating the rest, making it useful for large meshes with mission-critical workloads.