Creating Db2 HADR services for a multiple cluster topology

You can create Db2 HADR services and network policies for a multiple cluster topology.

About this task

The examples in this procedure are for an HADR setup with a primary and two standby databases. The primary and principal standby are in cluster1, and the auxiliary standby is in cluster2.

Procedure

Generate the HADR service and network policy definitions using the create_hadr_services script on the primary database pod.

Ports are always set up for primary and three standby databases, regardless of the your configuration.

oc exec -it c- db2oltp-primary -db2u-0 -- create_hadr_services --db-role primary --primary-name db2oltp-primary --standby-name db2oltp-standby --aux1-name db2oltp-aux --primary-ext-host api.cluster1.ibm.com --standby-ext-host api.cluster1.ibm.com --aux1-ext-host api.cluster2.ibm.com

apiVersion: v1
kind: Service
metadata:
  name: c-db2oltp-primary-hadr-svc
spec:
  selector:
    app: db2oltp-primary
    type: engine
  ports:
    - name: db2u-hadrp
      port: 60006
      targetPort: 60006
    - name: db2u-hadrs
      port: 60007
      targetPort: 60007
    - name: db2u-hadra1
      port: 60008
      targetPort: 60008
    - name: db2u-hadra2
      port: 60009
      targetPort: 60009
  type: NodePort
---
apiVersion: v1
kind: Service
metadata:
  name: c-db2oltp-primary-hadr-svc-ext
spec:
  type: ExternalName
  externalName: api.cluster1.ibm.com
---
apiVersion: v1
kind: Service
metadata:
  name: c-db2oltp-standby-hadr-svc-ext
spec:
  type: ExternalName
  externalName: api.cluster1.ibm.com
---
apiVersion: v1
kind: Service
metadata:
  name: c-db2oltp-aux-hadr-svc-ext
spec:
  type: ExternalName
  externalName: api.cluster2.ibm.com
---

Switch to the namespace that the primary database is deployed in, and use the oc apply -f command directly on the output to create the k8s services and network policies:

oc project ${NAMESPACE_PRIMARY}
oc exec -it c- db2oltp-primary-db2u-0 -- create_hadr_services --db-role primary --primary-name db2oltp-primary --standby-name db2oltp-standby --aux1-name db2oltp-aux --primary-ext-host api.cluster1.ibm.com --standby-ext-host api.cluster1.ibm.com --aux1-ext-host api.cluster2.ibm.com | oc apply -f -

Verify that the services and network policies were created:

One NodePort service that matches the Db2 deployment
Multiple ExternalName services – one for each database in the HADR configuration

oc get svc | grep hadr-svc

The following is an example of the returned output:

c-db2oltp-aux-hadr-svc-ext       ExternalName   <none>     api.cluster2.ibm.com   <none>   9s
c-db2oltp-primary-hadr-svc        NodePort       172.30.77.20     <none>   60006:32457/TCP,60007:31243/TCP,60008:30374/TCP,60009:30977/TCP   2m15s
c-db2oltp-primary-hadr-svc-ext    ExternalName   <none>  api.cluster1.ibm.com   <none>    9s
c-db2oltp-standby-hadr-svc-ext    ExternalName   <none>     api.cluster1.ibm.com   <none>

Run the following command to verify that the network policy was created in the same OpenShift® Container Platform project as the Db2 deployment
```
oc get networkpolicy | grep hadr-ext
```
The following is an example of the returned output:
```
c-db2oltp-primary-hadr-ext     formation_id=db2oltp-primary,type=engine         25s
```

Repeat steps 1 to 4 for each standby database, ensuring that you use the appropriate value for --db-role and that you are in the project that corresponds to the database:

# Create services for principal standby database in cluster1
oc project ${NAMESPACE_STANDBY}
oc exec -it c- db2oltp-standby-db2u-0 -- create_hadr_services --db-role standby --primary-name db2oltp-primary --standby-name db2oltp-standby --aux1-name db2oltp-aux --primary-ext-host api.cluster1.ibm.com --standby-ext-host api.cluster1.ibm.com --aux1-ext-host api.cluster2.ibm.com | oc apply -f -

# Check services on cluster1
oc get svc | grep hadr-svc
# Output:
c-db2oltp-aux-hadr-svc-ext       ExternalName   <none>           api.cluster2.ibm.com   <none>                                                                            9s
c-db2oltp-primary-hadr-svc        NodePort       172.30.77.20     <none>                            60006:32457/TCP,60007:31243/TCP,60008:30374/TCP,60009:30977/TCP                   2m15s
c-db2oltp-primary-hadr-svc-ext    ExternalName   <none>           api.cluster1.ibm.com   <none>                                                                            9s
c-db2oltp-standby-hadr-svc        NodePort       172.30.247.77     <none>                            60006:32649/TCP,60007:31384/TCP,60008:30473/TCP,60009:30652/TCP                   1m10s
c-db2oltp-standby-hadr-svc-ext    ExternalName   <none>           api.cluster1.ibm.com   <none>     

# Create services for auxiliary standby database in cluster2
oc project ${NAMESPACE_AUX}
oc exec -it c- db2oltp-aux-db2u-0 -- create_hadr_services --db-role aux1 --primary-name db2oltp-primary --standby-name db2oltp-standby --aux1-name db2oltp-aux --primary-ext-host api.cluster1.ibm.com --standby-ext-host api.cluster1.ibm.com --aux1-ext-host api.cluster2.ibm.com | oc apply -f –

# Check services on cluster2
oc get svc | grep hadr-svc
# Output:
c-db2oltp-aux-hadr-svc        NodePort       172.30.241.25     <none>                            60006:34578/TCP,60007:31546/TCP,60008:30698/TCP,60009:30448/TCP                   10s
c-db2oltp-aux-hadr-svc-ext       ExternalName   <none>           api.cluster2.ibm.com   <none>                                                                            9s
c-db2oltp-primary-hadr-svc-ext    ExternalName   <none>           api.cluster1.ibm.com   <none>                                                                            9s
c-db2oltp-standby-hadr-svc-ext    ExternalName   <none>           api.cluster1.ibm.com   <none>