Deploying common PostgreSQL cluster in HA.

[ricsanfre]

Scope

Deploy a common PosgreSQL cluster to provide database services to different applications. Currently, a postgreSQL instance is required by Keycloak, using bitnami packaged helm chart, but in the future to test microservices architecture, I will need to have other postgreSQL databases.

Requirements

• Create a common namespace: databases where common databases services can be deployed, so they can be used by different applications
• Deploy PosgreSQL cluster (HA deployment)
• Migrate Keycloak installation to use external PostgreSQL database-

Possible alternatives

• Bitnami PosgreSQL helm chart
• CloudNative-PG

[ricsanfre]

CloudNative-PG:

• DB Bootstrap
  • Support automatic initialization of the database: https://cloudnative-pg.io/documentation/1.23/bootstrap/
  • it includes automatic import from external database.
• HA using database replicas
  • Data replication from rw instance to read-only instances.
  • https://cloudnative-pg.io/documentation/1.23/replication/
• Backup and restore
  • Support backup and restore to Object Storage like Minio. https://cloudnative-pg.io/documentation/1.23/backup_barmanobjectstore/
  • The operator can orchestrate a continuous backup infrastructure that is based on the Barman Cloud too
• Monitoring:
  • For each PostgreSQL instance, the operator provides an exporter of metrics for Prometheus via HTTP, on port 9187, named metrics
  • https://cloudnative-pg.io/documentation/1.23/monitoring/

[ricsanfre]

CloudNative PG deployment and Keycloak external database in HA configuration solved partially with PR #458. Some commits on top of that PR fixed some of the initial issues. This commit fixes all issues 5bfaa97

Corresponding documentation updates added is commit f8c23cd