GKE on Google Cloud Platform Deployment

OpenMetadata supports the Installation and Running of Application on Google Kubernetes Engine through Helm Charts. However, there are some additional configurations which needs to be done as prerequisites for the same.

Prerequisites

Persistent Volumes with ReadWriteMany Access Modes

OpenMetadata helm chart depends on Airflow and Airflow expects a presistent disk that support ReadWriteMany (the volume can be mounted as read-write by many nodes).

The workaround is to create nfs-server disk on Google Kubernetes Engine and use that as the presistent claim and delpoy OpenMetadata by implementing the following steps in order.

Create NFS Share

Provision GCP Persistent Disk for Google Kubernetes Engine

Run the below command to create a gcloud compute zonal disk. For more information on Google Cloud Disk Options, please visit here.

gcloud compute disks create --size=100GB --zone=<zone_id> nfs-disk

Deploy NFS Server in GKE

Provision NFS backed PV and PVC for Airflow DAGs and Airflow Logs

Update <NFS_SERVER_CLUSTER_IP> with the NFS Service Cluster IP Address for below code snippets. You can get the clusterIP using the following command

kubectl get service nfs-server -o jsonpath='{.spec.clusterIP}'

Change owner and permission manually on disks

Since airflow pods run as non root users, they would not have write access on the nfs server volumes. In order to fix the permission here, spin up a pod with persistent volumes attached and run it once.

# permissions_pod.yml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: my-permission-pod
  name: my-permission-pod
spec:
  containers:
  - image: nginx
    name: my-permission-pod
    volumeMounts:
    - name: airflow-dags
      mountPath: /airflow-dags
    - name: airflow-logs
      mountPath: /airflow-logs
  volumes:
  - name: airflow-logs
    persistentVolumeClaim:
      claimName: openmetadata-dependencies-logs
  - name: airflow-dags
    persistentVolumeClaim:
      claimName: openmetadata-dependencies-dags
  dnsPolicy: ClusterFirst
  restartPolicy: Always

Run the below command to create the pod and fix the permissions

kubectl create -f permissions_pod.yml

Once the permissions pod is up and running, execute the below commands within the container.

kubectl exec --tty my-permission-pod --container my-permission-pod -- chown -R 50000 /airflow-dags /airflow-logs
# If needed
kubectl exec --tty my-permission-pod --container my-permission-pod -- chmod -R a+rwx /airflow-dags

Create OpenMetadata dependencies Values

Override openmetadata dependencies airflow helm values to bind the nfs persistent volumes for DAGs and logs.

# values-dependencies.yml
airflow:
  airflow:
    extraVolumeMounts:
      - mountPath: /airflow-logs
        name: nfs-airflow-logs
      - mountPath: /airflow-dags/dags
        name: nfs-airflow-dags
    extraVolumes:
      - name: nfs-airflow-logs
        persistentVolumeClaim:
          claimName: openmetadata-dependencies-logs
      - name: nfs-airflow-dags
        persistentVolumeClaim:
          claimName: openmetadata-dependencies-dags
    config:
      AIRFLOW__OPENMETADATA_AIRFLOW_APIS__DAG_GENERATED_CONFIGS: "/airflow-dags/dags"
  dags:
    path: /airflow-dags/dags
    persistence:
      enabled: false
  logs:
    path: /airflow-logs
    persistence:
      enabled: false

For more information on airflow helm chart values, please refer to airflow-helm.

Follow OpenMetadata Kubernetes Deployment to install and deploy helm charts with nfs volumes. When deploying openmeteadata dependencies helm chart, use the below command -

helm install openmetadata-dependencies open-metadata/openmetadata-dependencies --values values-dependencies.yaml