Increase PostgreSQL Database storage

The current configuration is:

Storage:

    postgresql:  Bound to volume app-pv-152-1g	1 GiB

postgresql deployment configuration:

    spec:
	template:
		spec:
		  volumes:
			- name: postgresql-data
			  persistentVolumeClaim:
				claimName: postgresql
	containers:
		  volumeMounts:
			- name: postgresql-data
			  mountPath: /var/lib/pgsql/data				
			  

Instructions to increase database storage:

step1: create a new storage for 5GiB

    postgresql2:  Bound to volume app-pv-???-1g	5 GiB			  

step2: update postgresql deployment configuration to mount current storage claim to postgresql-data-old and mount new storage claim to postgresql-data:

    spec:
	template:
		spec:
		  volumes:
			- name: postgresql-data
			  persistentVolumeClaim:
				claimName: postgresql2
			- name: postgresql-data-old
			  persistentVolumeClaim:
				claimName: postgresql
	containers:
		  volumeMounts:
			- name: postgresql-data
			  mountPath: /var/lib/pgsql/data				
			- name: postgresql-data-old
			  mountPath: /var/lib/pgsql/data-old

step3: verify if a new deployment for postgresql has happened, manually trigger one if not

step4: login to pod and copy data under /var/lib/pgsql/data-old	to /var/lib/pgsql/data			 

step5: update postgresql deployment configuration to remove postgresql-data-old:

    spec:
	template:
		spec:
		  volumes:
			- name: postgresql-data
			  persistentVolumeClaim:
				claimName: postgresql2
	containers:
		  volumeMounts:
			- name: postgresql-data
			  mountPath: /var/lib/pgsql/data				

step6: verify if a new deployment for postgresql has happened, manually trigger one if not

step7: verify if application works properly

further consideration: make sure a site maintenance page is displayed before we run the storage