1. oc login to your cluster, e.g. oc login -u admin -p admin https://mycluster.testing:6443

2. clone a EAP app deployment Git repo, eg. deployment.git

3. create env vars for namespaces and create them too (BTW I use to set WATCH_NAMESPACE=INSTALL_NAMESPACE)
export INSTALL_NAMESPACE="${USER}-dg8-eap74-namespace"
export WATCH_NAMESPACE="${USER}-dg8-eap74-watch-namespace"
oc new-project ${INSTALL_NAMESPACE}
oc new-project ${WATCH_NAMESPACE}

4. Install RHDG Operator
oc apply -f - << EOF
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
 name: datagrid
 namespace: ${INSTALL_NAMESPACE}
spec:
 targetNamespaces:
 - ${WATCH_NAMESPACE}
EOF

oc apply -f - << EOF
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
 name: datagrid-operator
 namespace: ${INSTALL_NAMESPACE}
spec:
 channel: 8.1.x
 installPlanApproval: Automatic
 name: datagrid
 source: redhat-operators
 sourceNamespace: openshift-marketplace
EOF

5. Check that the RHDG Operator is running, i.e. wait until operator pod is running
oc get pods -n ${INSTALL_NAMESPACE}

6. Create Infinispan CR
oc project ${WATCH_NAMESPACE}

oc apply -f - << EOF
apiVersion: infinispan.org/v1
kind: Infinispan
metadata:
  name: example-infinispan
spec:
  replicas: 1
EOF

7. Check that the RHDG service is up and running, i.e. wait until example-infinispan-* pod is running
oc get pods

8. Get Infinispan default credentials 
oc get secret example-infinispan-generated-secret -o jsonpath="{.data.identities\.yaml}" | base64 --decode | head -n 3 > user
export RHDG_ADDRESS=$(oc logs example-infinispan-0 | grep ISPN080034 | sed "s|^.*on ||g")
export USERNAME="$(cat user | grep username | sed 's|- username: ||g')"
export PASSWORD=$(cat user | grep password | sed 's|  password: ||g')
echo "$USERNAME - $PASSWORD"

9. Set a name for the EAP 73 app
EAP_APP_NAME=eap-app-73

10. Create a EAP ping service
cat << EOF > ping-service.yaml
apiVersion: v1
kind: Service
spec:
  clusterIP: None
  ports:
  - name: ping
    port: 8888
  selector:
	deploymentconfig: ${EAP_APP_NAME}
metadata:
  name: ${EAP_APP_NAME}-ping-service
  annotations:
	service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
	description: "The JGroups ping port for clustering."
EOF

oc create -f ping-service.yaml

11. Set the EAP image to be used to 7.3:latest
EAP_IMAGE=registry-proxy.engineering.redhat.com/rh-osbs/jboss-eap-7-eap73-openjdk8-openshift-rhel7:latest

12. Start the build
oc new-build ${EAP_IMAGE} --binary=true --name=${EAP_APP_NAME}
oc start-build ${EAP_APP_NAME} --from-dir=./deployment

13. Wait until the build is over, i.e. wait until eap-app-73-*-build is "Completed"
oc get pods

14. Install the EAP Operator
oc apply -f - << EOF
kind: "Subscription"
apiVersion: "operators.coreos.com/v1alpha1"
metadata:
  name: "eap-operator"
  namespace: "${INSTALL_NAMESPACE}"
spec:
  channel: alpha
  name: "eap"
  sourceNamespace: "openshift-marketplace"
  installPlanApproval: "Automatic"
  source: "redhat-operators"
EOF

15. Set a name for the EAP 73 app image
export APPLICATION_IMAGE=$(oc get is ${EAP_APP_NAME} -o jsonpath='{.status.tags[0].items[0].dockerImageReference}')

16. Create a WildFly CR running the pre-built app

oc apply -f - << EOF
apiVersion: wildfly.org/v1alpha1
kind: WildFlyServer
metadata:
  name: ${EAP_APP_NAME}
spec:
 applicationImage: '${APPLICATION_IMAGE}'
 replicas: 1
 env:
  - name: JGROUPS_PING_PROTOCOL
    value: 'dns.DNS_PING'
  - name: OPENSHIFT_DNS_PING_SERVICE_NAME
    value: 'eap-ping-service'
  - name: OPENSHIFT_DNS_PING_SERVICE_PORT
    value: '8888'
  - name: CACHE_USERNAME
    value: '${USERNAME}'
  - name: CACHE_PASSWORD
    value: '${PASSWORD}'
EOF

17. Check that the EAP 73 app is up and running, i.e. wait until eap-app-73-0 is ready
oc get pods

18. Set a name for the EAP 74 app
EAP_APP_NAME=eap-app-74

19. Create a EAP ping service
cat << EOF > ping-service.yaml
apiVersion: v1
kind: Service
spec:
  clusterIP: None
  ports:
  - name: ping
    port: 8888
  selector:
	deploymentconfig: ${EAP_APP_NAME}
metadata:
  name: ${EAP_APP_NAME}-ping-service
  annotations:
	service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
	description: "The JGroups ping port for clustering."
EOF

oc create -f ping-service.yaml

20. Set the EAP image to be used to 7.4:Beta
EAP_IMAGE=registry-proxy.engineering.redhat.com/rh-osbs/jboss-eap-7-tech-preview-eap74-openjdk11-openshift-rhel8:7.4.0.Beta-4

21. Start the build
oc new-build ${EAP_IMAGE} --binary=true --name=${EAP_APP_NAME}
oc start-build ${EAP_APP_NAME} --from-dir=./deployment

22. Wait until the build is over, i.e. wait until eap-app-74-*-build is "Completed"
oc get pods

23. Set a name for the EAP 73 app image
export APPLICATION_IMAGE=$(oc get is ${EAP_APP_NAME} -o jsonpath='{.status.tags[0].items[0].dockerImageReference}')

24. Create a WildFly CR running the pre-built app
oc apply -f - << EOF
apiVersion: wildfly.org/v1alpha1
kind: WildFlyServer
metadata:
  name: ${EAP_APP_NAME}
spec:
 applicationImage: '${APPLICATION_IMAGE}'
 replicas: 1
 env:
  - name: JGROUPS_PING_PROTOCOL
    value: 'dns.DNS_PING'
  - name: OPENSHIFT_DNS_PING_SERVICE_NAME
    value: '${EAP_APP_NAME}-ping-service'
  - name: OPENSHIFT_DNS_PING_SERVICE_PORT
    value: '8888'
  - name: CACHE_USERNAME
    value: '${USERNAME}'
  - name: CACHE_PASSWORD
    value: '${PASSWORD}'
EOF

25. Check that the EAP 74 app is NOT ready:
oc get pods
NAME                   READY   STATUS    RESTARTS   AGE
eap-app-73-0           1/1     Running   0          28m
eap-app-74-0           0/1     Running   11         29m
example-infinispan-0   1/1     Running   0          29m