PostgreSQL helm chart upgrade

[dbandin]

Nephos is currently using stable/postgresql chart as backend of few services, running deploy with the --upgrade flag, ignores postgresql version.

Should it be added to the workflow? Otherwise if the user is not aware, may keep old versions of postgreSQL across time.

The instruction for the manual upgrade are in the helm chart repo, it will vary depending on the chart version -> https://github.com/helm/charts/tree/master/stable/postgresql

[alexvicegrab]

@dbandin, about PostgreSQL, yes, there have been upgrades that break the build, but given that we have added the ability to set the specific version of a chart, we should not need to hardcode it.

[alexvicegrab]

And yes, an upgrade to PostgreSQL major version that preserves data will be laborious and should probably involve backing up the data and generating a new deployment to which we transfer the data.

[dbandin]

@alexvicegrab Thanks for the answers!. The issue was open to see if we can consider adding those steps into nephos when we upgrade hyperledger, upgrade also postgres, preserving the data or re-generating it.
Indeed as described in the link I posted, the upgrade preserving data involves doing a pg_dump of the current instance and importing the data in the new deployment.