Multiple K8S containers connecting to Google Cloud SQL through proxy

Question

I would like to connect my Kubernetes cluster to Google Cloud SQL.

I have at least 10 different deployed pods which presently connect to MySQL [docker image deployed to k8s] using a JDBC url + username/password.

It it possible to use a single instance of the Google Cloud SQL Proxy and connect all the pods through this proxy to the Cloud SQL database? Ideally I would like to replace the mysql running in the container with the proxy.

I would prefer not having to run the proxy inside each deployment. The only samples I found seem to indicate the proxy needs to be declared in each deployment.

Answer 1

I found a solution.

Deploy the proxy with the yml below, and expose the deployment as a service. Most importantly, make the proxy listen on 0.0.0.0, instead of default 127.0.0.1. All the secrets as per the Google Cloud sql documentation

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: mysql
spec:
  replicas: 1
  template:
    metadata:
      name: mysql
      labels:
        name: mysql
    spec:
      containers:
         - image: b.gcr.io/cloudsql-docker/gce-proxy:1.05
           name: cloudsql-proxy
           command: ["/cloud_sql_proxy", "--dir=/cloudsql",
                     "-instances=MYSQL:ZONE:DATABASE_INSTANCE=tcp:0.0.0.0:3306",
                     "-credential_file=/secrets/cloudsql/credentials.json"]
           volumeMounts:
             - name: cloudsql-oauth-credentials
               mountPath: /secrets/cloudsql
               readOnly: true
             - name: ssl-certs
               mountPath: /etc/ssl/certs
           ports:
             - containerPort: 3306
               name: mysql
      volumes:
        - name: cloudsql-oauth-credentials
          secret:
            secretName: cloudsql-oauth-credentials
        - name: ssl-certs
          hostPath:
            path: /etc/ssl/certs

The solution is slightly more expensive than having the proxy in the same deployment as the client software, since there is an extra TCP connection.

However there are many benefits:

• Much simpler and doesn't require modifying existing K8S deployment files
• Allows switching the implementation to a MySQL Docker container or using the Google Cloud SQL proxy without any modifications to the client configuration.