:_mod-docs-content-type: PROCEDURE

// This assembly is included in the following assemblies:
//
// assembly-using-multiple-cluster-operators.adoc

[id='assembly-configuring-proxy-config-cluster-operator-{context}']
= Configuring Cluster Operator replicas

[role="_abstract"]
To run additional Cluster Operator replicas in standby mode, you will need to increase the number of replicas and enable leader election.
To configure leader election, use the leader election environment variables.

To make the required changes, configure the following Cluster Operator installation files located in `install/cluster-operator/`: 

* 060-Deployment-strimzi-cluster-operator.yaml
* 022-ClusterRole-strimzi-cluster-operator-role.yaml
* 022-RoleBinding-strimzi-cluster-operator.yaml

Leader election has its own `ClusterRole` and `RoleBinding` RBAC resources that target the namespace where the Cluster Operator is running, rather than the namespace it is watching. 

The default deployment configuration creates a `Lease` resource called `strimzi-cluster-operator` in the same namespace as the Cluster Operator.
The Cluster Operator uses leases to manage leader election. 
The RBAC resources provide the permissions to use the `Lease` resource.
If you use a different `Lease` name or namespace, update the `ClusterRole` and `RoleBinding` files accordingly.

.Prerequisites

* You need an account with permission to create and manage `CustomResourceDefinition` and RBAC (`ClusterRole`, and `RoleBinding`) resources.

.Procedure

Edit the `Deployment` resource that is used to deploy the Cluster Operator, which is defined in the `060-Deployment-strimzi-cluster-operator.yaml` file.

. Change the `replicas` property from the default (1) to a value that matches the required number of replicas.
+
[source,yaml,numbered,options="nowrap",highlight='12']
.Increasing the number of Cluster Operator replicas
----
include::../install/cluster-operator/060-Deployment-strimzi-cluster-operator.yaml[lines=1..7] 
  replicas: 3 
----

. Check that the leader election `env` properties are set.
+
If they are not set, configure them.
+
To enable leader election, `STRIMZI_LEADER_ELECTION_ENABLED` must be set to `true` (default).
+
In this example, the name of the lease is changed to `my-strimzi-cluster-operator`.
+
[source,yaml,numbered,options="nowrap",highlight='12']
.Configuring leader election environment variables for the Cluster Operator
----
# ... 
spec
  containers:
    - name: strimzi-cluster-operator
      # ...
      env:
        - name: STRIMZI_LEADER_ELECTION_ENABLED
          value: "true"
        - name: STRIMZI_LEADER_ELECTION_LEASE_NAME
          value: "my-strimzi-cluster-operator"
        - name: STRIMZI_LEADER_ELECTION_LEASE_NAMESPACE
            valueFrom:
              fieldRef:
                fieldPath: metadata.namespace
        - name: STRIMZI_LEADER_ELECTION_IDENTITY
            valueFrom:
              fieldRef:
                fieldPath: metadata.name
----
+
For a description of the available environment variables, see xref:con-configuring-cluster-operator-leader-election-{context}[].
+
If you specified a different name or namespace for the `Lease` resource used in leader election, update the RBAC resources.

. (optional) Edit the `ClusterRole` resource in the `022-ClusterRole-strimzi-cluster-operator-role.yaml` file.
+
Update `resourceNames` with the name of the `Lease` resource.
+ 
[source,yaml,numbered,options="nowrap",highlight='12']
.Updating the ClusterRole references to the lease 
----
include::../install/cluster-operator/022-ClusterRole-strimzi-cluster-operator-role.yaml[lines=1..9;21]
      - my-strimzi-cluster-operator
# ...      
----

. (optional) Edit the `RoleBinding` resource in the `022-RoleBinding-strimzi-cluster-operator.yaml` file.
+
Update `subjects.name` and `subjects.namespace` with the name of the `Lease` resource and the namespace where it was created.
+ 
[source,yaml,numbered,options="nowrap",highlight='12']
.Updating the RoleBinding references to the lease 
----
include::../install/cluster-operator/022-RoleBinding-strimzi-cluster-operator.yaml[lines=1..8]
    name: my-strimzi-cluster-operator
    namespace: myproject
# ...
----

. Deploy the Cluster Operator:
+
[source,shell,subs="+quotes,attributes+"]
kubectl create -f install/cluster-operator -n myproject

. Check the status of the deployment:
+
[source,shell,subs="+quotes"]
----
kubectl get deployments -n myproject
----
+
.Output shows the deployment name and readiness
[source,shell,subs="+quotes"]
----
NAME                      READY  UP-TO-DATE  AVAILABLE
strimzi-cluster-operator  3/3    3           3
----
+
`READY` shows the number of replicas that are ready/expected.
The deployment is successful when the `AVAILABLE` output shows the correct number of replicas.

