Creating a network policy for built-in etcd for Db2

To use the built-in etcd store from one of the Db2 deployments in your HADR configuration, you must create a network policy to allow other database deployments to communicate with the etcd pod.

About this task

Creating a network policy will allow incoming connections to the etcd pod. For more details on the built-in etcd store, see Setting up an etcd store for HADR in Db2.

Important: The built-in etcd store is not to be used in production environments.

Procedure

Create variables referencing the Db2uCluster or Db2uInstance name and namespace being used. Use the corresponding variables for Db2uCluster or Db2uInstance with the database deployment containing the built-in etcd store you are using.
```
export DB2_CR_ID=<db2ucluster_name/db2uinstance_name>
export NAMESPACE=<namespace_of_db2ucluster/namespace_of_db2uinstance>>
```

Create a network policy for the etcd pod by modifying, then running the following scripts for Db2uCluster or Db2uInstance.

cat <<EOF | oc apply -f -
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: c-${DB2_CR_ID}-etcd-ext
  namespace: ${NAMESPACE}
spec:
  ingress:
  - ports:
    - port: 2379
      protocol: TCP
  podSelector:
    matchLabels:
      formation_id: ${DB2_CR_ID}
      component: etcd
  policyTypes:
  - Ingress
EOF

Results

You can now use the network policy to access etcd for automated failover.

What to do next

See Setting up the HADR configuration for Db2.