Support Secrets for postgresql Configuration

[tjellicoe-tpzuk]

Currently, the config details for the postgresql database are stored within the zoo-project-dru-zoo-project-config configmap as raw text. However, we should be able to define these as secrets for use in the zookernel pods, for example for the username and password.
Can we update the zookernel pod to read these from environment variables, rather than the configmap, so that they can be configured as secrets?

[gfenoy]

This feature request has been implemented and is available in ZOO-Project-DRU version 0.3.36 Helm Chart.

To enable the use of secrets, you should create a secret storing the desired information and use this secret from the ZOO kernel and the ZOO-FPM pods.

Create the secret

First, you need to create the secret where you want to store information such as:

• host will be available from PGHOST,
• port will be available from PGPORT,
• database will be available from PGDATABASE,
• username will be available from PGUSER,
• password will be available from PGPASSWORD.

You must also provide a password for the PostgreSQL administrator using the key postgres-password.

I've included an example of the creation of such a secret below.

kubectl create secret generic postgresql-secret \
  --from-literal=password=zoo \
  --from-literal=username=zoo \
  --from-literal=postgres-password=zoo \
  -n zoo --dry-run -o yaml | kubectl apply -f -

In this example, we only define the required postgres-password, username and password. Consequently, other information, such as host, port and database will be fetched from the main.cfg available in the configmap. You are free to update any other listed keys.

Use the secret

Modify your values.yaml to have the global.postgresql.auth.existingSecret parameter set to postgresql-secret.

The connection to PostgreSQL will use the environment variables available from the ZOO-Kernel and the ZOO-FPM pods.

Please let me know if it matches your original expectations.

[gfenoy]

@rconway, please review this enhancement request and let us know if anything else is required.

[rconway]

@tjellicoe-tpzuk Does this updated chart 0.3.36 meet your needs?