Setup PG HA on Kubernetes.md

Create cluster

gcloud container clusters create "gke-px" \
--zone "asia-southeast1-a" \
--cluster-version "1.20.8-gke.900" \
--machine-type "n1-standard-4" \
--image-type "UBUNTU" \
--disk-type "pd-ssd" \
--disk-size "100" \
--num-nodes "3" \
--enable-stackdriver-kubernetes \
--network "default" \
--addons HorizontalPodAutoscaling,HttpLoadBalancing

get credentials

gcloud container clusters get-credentials gke-px --zone asia-southeast1-a

create a ClusterRoleBinding with the following command:

kubectl create clusterrolebinding cluster-admin-binding \
--clusterrole cluster-admin \
--user $(gcloud config get-value account)

Install portwork

kubectl create -f https://install.portworx.com/?comp=pxoperator

Generate the specs

go to https://central.portworx.com/
* sign in or sign up
* create spec wizard
* copy spec to clipboard
* on GKE console, execute the copied command:

kubectl apply -f 'https://install.portworx.com/2.7?operator=true&mc=false&kbver=&oem=esse&user=cec3e306-f28f-11eb-a2c5-c24e499c7467&b=true&s=%22type%3Dpd-ssd%2Csize%3D150%22&kd=type%3Dpd-standard%2Csize%3D150&c=px-cluster-58950afe-5f17-4d9e-9b9c-8693a1c32a69&stork=true&csi=false&lh=true&tel=false&st=k8s'

Creating a Postgres storage class in Kubernetes

cat > px-repl3-sc.yaml <<EOF
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
    name: px-repl3-sc
provisioner: kubernetes.io/portworx-volume
parameters:
   repl: "3"
   io_profile: "db_remote"
   priority_io: "high"
EOF

then:

kubectl create -f px-repl3-sc.yaml

Creating a Postgres PVC

cat > px-postgres-pvc.yaml <<EOF
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
   name: px-postgres-pvc
   annotations:
     volume.beta.kubernetes.io/storage-class: px-repl3-sc
spec:
   accessModes:
     - ReadWriteOnce
   resources:
     requests:
       storage: 1Gi
EOF

then

kubectl create -f px-postgres-pvc.yaml

The password for PostgreSQL will be created as a secret. Run the following commands to create the secret in the correct format.

echo postgres123 > password.txt
tr -d '\n' <password.txt > .strippedpassword.txt && mv .strippedpassword.txt password.txt
kubectl create secret generic postgres-pass --from-file=password.txt

How to deploy Postgres on GKE

cat > postgres-app.yaml <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
  name: postgres
spec:
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
    type: RollingUpdate
  replicas: 1
  selector:
    matchLabels:
      app: postgres
  template:
    metadata:
      labels:
        app: postgres
    spec:
      schedulerName: stork
      containers:
      - name: postgres
        image: postgres:9.5
        imagePullPolicy: "Always"
        ports:
        - containerPort: 5432
        env:
        - name: POSTGRES_USER
          value: pgbench
        - name: PGUSER
          value: pgbench
        - name: POSTGRES_PASSWORD
          valueFrom:
            secretKeyRef:
              name: postgres-pass
              key: password.txt
        - name: PGBENCH_PASSWORD
          value: superpostgres
        - name: PGDATA
          value: /var/lib/postgresql/data/pgdata
        volumeMounts:
        - mountPath: /var/lib/postgresql/data
          name: postgredb
      volumes:
      - name: postgredb
        persistentVolumeClaim:
          claimName: px-postgres-pvc
EOF

then

``sh kubectl create -f postgres-app.yaml

``

Make sure that the Postgres pods are in running state.

kubectl get pods -l app=postgres -o wide --watch

We can inspect the Portworx volume by accessing the pxctl tool running with the Postgres Pod.

VOL=`kubectl get pvc | grep px-postgres-pvc | awk '{print $3}'`
PX_POD=$(kubectl get pods -l name=portworx -n kube-system -o jsonpath='{.items[0].metadata.name}')
kubectl exec -it $PX_POD -n kube-system -- /opt/pwx/bin/pxctl volume inspect ${VOL}