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Using private Docker registry

KubeDB supports using private Docker registry. This tutorial will show you how to run KubeDB managed PostgreSQL database using private Docker images.

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using minikube.

To keep things isolated, this tutorial uses a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

Note: YAML files used in this tutorial are stored in docs/examples/postgres folder in GitHub repository kubedb/cli.

Prepare Private Docker Registry

• You will also need a docker private registry or private repository. In this tutorial we will use private repository of docker hub.

• You have to push the required images from KubeDB’s Docker hub account into your private registry. For postgres, push DB_IMAGE, TOOLS_IMAGE, EXPORTER_IMAGE of following PostgresVersions, where deprecated is not true, to your private registry.

  $ kubectl get postgresversions -n kube-system  -o=custom-columns=NAME:.metadata.name,VERSION:.spec.version,DB_IMAGE:.spec.db.image,TOOLS_IMAGE:.spec.tools.image,EXPORTER_IMAGE:.spec.exporter.image,DEPRECATED:.spec.deprecated
  NAME       VERSION   DB_IMAGE                   TOOLS_IMAGE                      EXPORTER_IMAGE                    DEPRECATED
  10.2       10.2      kubedb/postgres:10.2       kubedb/postgres-tools:10.2       kubedb/operator:0.8.0             true
  10.2-v1    10.2      kubedb/postgres:10.2-v2    kubedb/postgres-tools:10.2-v2    kubedb/postgres_exporter:v0.4.6   true
  10.2-v2    10.2      kubedb/postgres:10.2-v3    kubedb/postgres-tools:10.2-v2    kubedb/postgres_exporter:v0.4.7   <none>
  10.6       10.6      kubedb/postgres:10.6       kubedb/postgres-tools:10.6       kubedb/postgres_exporter:v0.4.7   <none>
  11.1       11.1      kubedb/postgres:11.1       kubedb/postgres-tools:11.1       kubedb/postgres_exporter:v0.4.7   <none>
  9.6        9.6       kubedb/postgres:9.6        kubedb/postgres-tools:9.6        kubedb/operator:0.8.0             true
  9.6-v1     9.6       kubedb/postgres:9.6-v2     kubedb/postgres-tools:9.6-v2     kubedb/postgres_exporter:v0.4.6   true
  9.6-v2     9.6       kubedb/postgres:9.6-v3     kubedb/postgres-tools:9.6-v2     kubedb/postgres_exporter:v0.4.7   <none>
  9.6.7      9.6.7     kubedb/postgres:9.6.7      kubedb/postgres-tools:9.6.7      kubedb/operator:0.8.0             true
  9.6.7-v1   9.6.7     kubedb/postgres:9.6.7-v2   kubedb/postgres-tools:9.6.7-v2   kubedb/postgres_exporter:v0.4.6   true
  9.6.7-v2   9.6.7     kubedb/postgres:9.6.7-v3   kubedb/postgres-tools:9.6.7-v2   kubedb/postgres_exporter:v0.4.7   <none>
  

  Docker hub repositories:

• kubedb/operator

• kubedb/postgres

• kubedb/postgres-tools

• kubedb/postgres_exporter

Create ImagePullSecret

ImagePullSecrets is a type of a Kubernetes Secret whose sole purpose is to pull private images from a Docker registry. It allows you to specify the url of the docker registry, credentials for logging in and the image name of your private docker image.

Run the following command, substituting the appropriate uppercase values to create an image pull secret for your private Docker registry:

$ kubectl create secret -n demo docker-registry myregistrykey \
  --docker-server=DOCKER_REGISTRY_SERVER \
  --docker-username=DOCKER_USER \
  --docker-email=DOCKER_EMAIL \
  --docker-password=DOCKER_PASSWORD
secret/myregistrykey created

If you wish to follow other ways to pull private images see official docs of kubernetes.

Note; If you are using kubectl 1.9.0, update to 1.9.1 or later to avoid this issue.

Install KubeDB operator

When installing KubeDB operator, set the flags --docker-registry and --image-pull-secret to appropriate value. Follow the steps to install KubeDB operator properly in cluster so that to points to the DOCKER_REGISTRY you wish to pull images from.

Create PostgresVersion CRD

KubeDB uses images specified in PostgresVersion crd for database, backup and exporting prometheus metrics. You have to create a PostgresVersion crd specifying images from your private registry. Then, you have to point this PostgresVersion crd in spec.version field of Postgres object. For more details about PostgresVersion crd, please visit here.

Here, is an example of PostgresVersion crd. Replace <YOUR_PRIVATE_REGISTRY> with your private registy.

apiVersion: catalog.kubedb.com/v1alpha1
kind: PostgresVersion
metadata:
  name: "pvt-9.6"
  labels:
    app: kubedb
spec:
  version: "9.6"
  db:
    image: "<YOUR_PRIVATE_REGISTRY>/postgres:9.6-v3"
  exporter:
    image: "<YOUR_PRIVATE_REGISTRY>/postgres_exporter:v0.4.6"
  tools:
    image: "<YOUR_PRIVATE_REGISTRY>/postgres-tools:9.6-v2"

Now, create the PostgresVersion crd,

$ kubectl apply -f pvt-postgresversion.yaml
postgresversion.kubedb.com/pvt-9.6 created

Deploy PostgreSQL database from Private Registry

While deploying PostgreSQL from private repository, you have to add myregistrykey secret in Postgres spec.podTemplate.spec.imagePullSecrets and specify pvt-9.6 in spec.version field.

Below is the Postgres object we will create in this tutorial

apiVersion: kubedb.com/v1alpha1
kind: Postgres
metadata:
  name: pvt-reg-postgres
  namespace: demo
spec:
  version: "pvt-9.6"
  storage:
    storageClassName: "standard"
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  podTemplate:
    spec:
      imagePullSecrets:
      - name: myregistrykey

Now run the command to create this Postgres object:

$ kubectl create -f https://raw.githubusercontent.com/kubedb/cli/0.10.0/docs/examples/postgres/private-registry/pvt-reg-postgres.yaml
postgres.kubedb.com/pvt-reg-postgres created

To check if the images pulled successfully from the repository, see if the PostgreSQL is in Running state:

$ kubectl get pods -n demo --selector="kubedb.com/name=pvt-reg-postgres"
NAME                 READY     STATUS    RESTARTS   AGE
pvt-reg-postgres-0   1/1       Running   0          3m

Snapshot

You can specify imagePullSecret for Snapshot objects in spec.podTemplate.spec.imagePullSecrets field of Snapshot object. If you are using scheduled backup, you can also provide imagePullSecret in backupSchedule.podTemplate.spec.imagePullSecrets field of Postgres crd. KubeDB also reuses imagePullSecret for Snapshot object from spec.podTemplate.spec.imagePullSecrets field of Postgres crd.

Cleaning up

To cleanup the Kubernetes resources created by this tutorial, run:

kubectl patch -n demo pg/pvt-reg-postgres -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"
kubectl delete -n demo pg/pvt-reg-postgres

kubectl delete ns demo

If you would like to uninstall KubeDB operator, please follow the steps here.

Next Steps

• Learn about taking instant backup of PostgreSQL database using KubeDB Snapshot.
• Learn how to schedule backup of PostgreSQL database.
• Learn about initializing PostgreSQL with Script.
• Learn about initializing PostgreSQL from KubeDB Snapshot.
• Want to setup PostgreSQL cluster? Check how to configure Highly Available PostgreSQL Cluster
• Monitor your PostgreSQL database with KubeDB using built-in Prometheus.
• Monitor your PostgreSQL database with KubeDB using CoreOS Prometheus Operator.
• Want to hack on KubeDB? Check our contribution guidelines.