Component Replication

To replicate component, replication policy is added as a built-in policy. It can be only used together with deploy workflow step. If using replication policy in deploy workflow step, a new field context.replicaKey will be added to when rendering the component. You can use this field to dispatch the resources to the same cluster with different replicaKey.

note

policy is only supported in KubeVela version 1.6.0+.

context.replicaKey is always used in metadata.name in ComponentDefinition or TraitDefinition when dispatching resources to avoid name conflict. We’ll see it later in the example.

The following ComponentDefinition is an example which make use of replication policy. It uses context.replicaKey to add suffixes to resource names.

Copy the definition to file replica-webservice.cue and apply the definition:

Then application will dispatch two deployments and two services:

There are three policies that can use in deploy step: topology, and replication. They can be used together to both replicate component and dispatch them to different clusters. Here is the rules when they are use together:

1. The applying order of policies is topology -> override -> replication. More information can be found in Multi cluster Application
   • override modifies the component properties. If not used, no properties will be changed.
   • replication will turn one component into multiple ones.

note