Delete an Azure Arc-enabled PostgreSQL Hyperscale server group

This document describes the steps to delete a server group from your Azure Arc setup.

Note

As a preview feature, the technology presented in this article is subject to Supplemental Terms of Use for Microsoft Azure Previews.

The latest updates are available in the release notes.

For the current update, deployment of Arc data controller in direct connectivity mode is only supported from Azure portal.

Delete the server group

As an example, let's consider we want to delete the postgres01 instance from the below setup:

az postgres arc-server list --k8s-namespace <namespace> --use-k8s
Name        State    Workers
----------  -------  ---------
postgres01  Ready    3

The general format of the delete command is:

az postgres arc-server delete -n <server group name> --k8s-namespace <namespace> --use-k8s

When you execute this command, you will be requested to confirm the deletion of the server group. If you are using scripts to automate deletions you will need to use the --force parameter to bypass the confirmation request. For example, you would run a command like:

az postgres arc-server delete -n <server group name> --force --k8s-namespace <namespace> --use-k8s

For more details about the delete command, run:

az postgres arc-server delete --help 

Delete the server group used in this example

az postgres arc-server delete -n postgres01 --k8s-namespace <namespace> --use-k8s

Reclaim the Kubernetes Persistent Volume Claims (PVCs)

Deleting a server group does not remove its associated PVCs. This is by design. The intention is to help the user to access the database files in case the deletion of instance was accidental. Deleting PVCs is not mandatory. However it is recommended. If you don't reclaim these PVCs, you'll eventually end up with errors as your Kubernetes cluster will think it's running out of disk space. To reclaim the PVCs, take the following steps:

1. List the PVCs for the server group you deleted

To list the PVCs, run this command:

kubectl get pvc [-n <namespace name>]

It returns the list of PVCs, in particular the PVCs for the server group you deleted. For example:

kubectl get pvc
NAME                                         STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
data-few7hh0k4npx9phsiobdc3hq-postgres01-0   Bound    pvc-72ccc225-dad0-4dee-8eae-ed352be847aa   5Gi        RWO            default        2d18h
data-few7hh0k4npx9phsiobdc3hq-postgres01-1   Bound    pvc-ce6f0c51-faed-45ae-9472-8cdf390deb0d   5Gi        RWO            default        2d18h
data-few7hh0k4npx9phsiobdc3hq-postgres01-2   Bound    pvc-5a863ab9-522a-45f3-889b-8084c48c32f8   5Gi        RWO            default        2d18h
data-few7hh0k4npx9phsiobdc3hq-postgres01-3   Bound    pvc-00e1ace3-1452-434f-8445-767ec39c23f2   5Gi        RWO            default        2d15h
logs-few7hh0k4npx9phsiobdc3hq-postgres01-0   Bound    pvc-8b810f4c-d72a-474a-a5d7-64ec26fa32de   5Gi        RWO            default        2d18h
logs-few7hh0k4npx9phsiobdc3hq-postgres01-1   Bound    pvc-51d1e91b-08a9-4b6b-858d-38e8e06e60f9   5Gi        RWO            default        2d18h
logs-few7hh0k4npx9phsiobdc3hq-postgres01-2   Bound    pvc-8e5ad55e-300d-4353-92d8-2e383b3fe96e   5Gi        RWO            default        2d18h
logs-few7hh0k4npx9phsiobdc3hq-postgres01-3   Bound    pvc-f9e4cb98-c943-45b0-aa07-dd5cff7ea585   5Gi        RWO            default        2d15h

There are 8 PVCs for this server group.

2. Delete each of the PVCs

Delete the data and log PVCs for each of the PostgreSQL Hyperscale nodes (Coordinator and Workers) of the server group you deleted.

The general format of this command is:

kubectl delete pvc <name of pvc>  [-n <namespace name>]

For example:

kubectl delete pvc data-few7hh0k4npx9phsiobdc3hq-postgres01-0
kubectl delete pvc data-few7hh0k4npx9phsiobdc3hq-postgres01-1
kubectl delete pvc data-few7hh0k4npx9phsiobdc3hq-postgres01-2
kubectl delete pvc data-few7hh0k4npx9phsiobdc3hq-postgres01-3
kubectl delete pvc logs-few7hh0k4npx9phsiobdc3hq-postgres01-0
kubectl delete pvc logs-few7hh0k4npx9phsiobdc3hq-postgres01-1
kubectl delete pvc logs-few7hh0k4npx9phsiobdc3hq-postgres01-2
kubectl delete pvc logs-few7hh0k4npx9phsiobdc3hq-postgres01-3

Each of these kubectl commands will confirm the successful deleting of the PVC. For example:

persistentvolumeclaim "data-postgres01-0" deleted

Note

As indicated, not deleting the PVCs might eventually get your Kubernetes cluster in a situation where it will throw errors. Some of these errors may include being unable to create, read, update, delete resources from the Kubernetes API, or being able to run commands like az arcdata dc export as the controller pods may be evicted from the Kubernetes nodes because of this storage issue (normal Kubernetes behavior).

For example, you may see messages in the logs similar to:

Annotations:    microsoft.com/ignore-pod-health: true  
Status:         Failed  
Reason:         Evicted  
Message:        The node was low on resource: ephemeral-storage. Container controller was using 16372Ki, which exceeds its request of 0.

Next step

Create Azure Arc-enabled PostgreSQL Hyperscale