Single Cluster

Setting up a basic Cluster is pretty easy, we just need the minimum Definiton of a cluster-manifest which can also be find in the operator-tutorials repo on github. We need the following Definitions for the basic cluster.

minimal Single Cluster

apiVersion: cpo.opensource.cybertec.at/v1
kind: postgresql
metadata:
  name: cluster-1
spec:
  dockerImage: "docker.io/cybertecpostgresql/cybertec-pg-container:postgres-16.4-1"
  numberOfInstances: 1
  postgresql:
    version: "16"
  resources:
    limits:
      cpu: 500m
      memory: 500Mi
    requests:
      cpu: 500m
      memory: 500Mi
  volume:
    size: 5Gi

Based on this Manifest the Operator will deploy a single-Node-Cluster based on the defined dockerImage and start the included Postgres-16-Server. Also created is a volume based on your default-storage Class. The Ressource-Definiton means, that we reserve a half cpu and a half GB Memory for this Cluster with the same Definition as limit.

After some seconds we should see, that the operator creates our cluster based on the declared definitions.

kubectl get pods
-----------------------------------------------------------------------------
NAME                             | READY  | STATUS           | RESTARTS | AGE
cluster-1-0                      | 1/1    | Running          | 0        | 50s

We can now starting to modify our cluster with some more Definitons.

Use a specific Storageclass

spec:
  ...
  volume:
    size: 5Gi
    storageClass: default-provisioner
  ...

Using the storageClass-Definiton allows us to define a specific storageClass for this Cluster. Please ensure, that the storageClass exists and is usable. If a Volume cannot provide the Volume will stand in the pending-State as like the Database-Pod.

Expanding Volume

The Operator allows to you expand your volume if the storage-System is able to do this.

spec:
  ...
  volume:
    size: 10Gi
    storageClass: default-provisioner
  ...

This will trigger the expand of your Cluster-Volumes. It will need some time and you can check the current state inside the pvc.

kubectl get pvc pgdata-cluster-1-0 -o yaml
-------------------------------------------------------
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
  storageClassName: crc-csi-hostpath-provisioner
  volumeMode: Filesystem
  volumeName: pvc-800d7ecc-2d5f-4ef4-af83-1cd94c766d37
status:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 5Gi
  phase: Bound

Creating additonal Volumes

The Operator allows you to modify your cluster with additonal Volumes.

spec:
  ...
  additionalVolumes:
    - name: empty
      mountPath: /opt/empty
      targetContainers:
        - all
      volumeSource:
        emptyDir: {}

This example will create an emptyDir and mount it to all Containers inside the Database-Pod.

Specific Settings for aws gp3 Storage

For the gp3 Storage aws you can define more informations

  volume:
    size: 1Gi
    storageClass: gp3
    iops: 1000  # for EBS gp3
    throughput: 250  # in MB/s for EBS gp3

The defined IOPS and Throughput will include in the PersistentVolumeClaim and send to the storage-Provisioner. Please keep in Mind, that on aws there is a CoolDown-Time as a limitation defined. For new Changes you need to wait 6 hours. Please also ensure to check the default and allowed values for IOPS and Throughput AWS docs.

To ensure that the settings are updates properly please define the Operator-Configuration ‘storage_resize_mode’ from default to ‘mixed’