PostgreSQL

PostgreSQL or “Postgres” is an open source object-relational database management system (ORDBMS).

Postgres is deployed across a wide variety of platforms with a mix of workloads ranging from small, single-node use cases to large internet-facing clusters with many concurrent users.

Before you start, ensure you have Ondat installed and ready on a Kubernetes cluster. If you need to setup Ondat on Kubernetes then see our guide to installing Ondat on Kubernetes.

Deploying PostgreSQL on Kubernetes

1. You can find the latest files in the Ondat use cases repository

   git clone https://github.com/storageos/use-cases.git storageos-usecases
   
   

   PersistentVolumeClaim and Pod definition excerpts

   kind: PersistentVolumeClaim
   metadata:
   name: pg-data
   storageClassName: "storageos"
   
   ...
   
   kind: Pod
   metadata:
   name: postgress
   spec:
   securityContext:
   fsGroup: 26
   containers:
   - name: pg
     image: crunchydata/crunchy-postgres:centos7-10.4-1.8.3
     volumeMounts:
       - mountPath: /pgdata
         name: data
   ...
   volumes:
   - name: data
     persistentVolumeClaim:
       claimName: pg-data
   

   This excerpt is from the PersistentVolumeClaim and Pod definition. The pod definition references the pg-data VolumeClaim so storage is dynamically provision storage, using the Ondat storage class. Dynamic provisioning occurs as a volumeMount has been declared with the same name as a Volume Claim.

2. Move into the PostgreSQL examples folder and create the objects

   cd storageos-usecases
   kubectl create -f ./postgres
   

3. Confirm PostgreSQL is up and running.

   $ kubectl get pod postgres-0 -w
   NAME         READY   STATUS    RESTARTS   AGE
   postgres-0   1/1     Running   0          1m
   

4. Connect to the PostgreSQL client pod and connect to the PostgreSQL server through the service.

   $ kubectl exec -it postgres-0 -- psql -h postgres-0.postgres -U primaryuser postgres -c "\l"
   Password for user primaryuser: password
                           List of Databases
     Name    |  Owner   | Encoding  | Collate | Ctype |   Access privileges
   +=========================================================================+
   postgres  | postgres | SQL_ASCII | C       | C     |
   template0 | postgres | SQL_ASCII | C       | C     | =c/postgres          +
             |          |           |         |       | postgres=CTc/postgres
   template1 | postgres | SQL_ASCII | C       | C     | =c/postgres          +
             |          |           |         |       | postgres=CTc/postgres
   userdb    | postgres | SQL_ASCII | C       | C     | =Tc/postgres         +
             |          |           |         |       | postgres=CTc/postgres+
             |          |           |         |       | testuser=CTc/postgres
   (4 rows)
   

   The password for the primary user is password. You can see this is set in the ConfigMap file.

Configuration

If you need custom startup options, you can edit the ConfigMap file 15-postgresd-configmap.yaml with your desired PostgreSQL configuration settings.