Connection pooler support
Add support for a connection pooler. The idea is to make it generic enough to
be able to switch between different implementations (e.g. pgbouncer or
odyssey). Operator needs to create a deployment with pooler and a service for
it to access.
For connection pool to work properly, a database needs to be prepared by
operator, namely a separate user have to be created with an access to an
installed lookup function (to fetch credential for other users).
This setups is supposed to be used only by robot/application users. Usually a
connection pool implementation is more CPU bounded, so it makes sense to create
several pods for connection pool with more emphasize on cpu resources. At the
moment there are no special affinity or tolerations assigned to bring those
pods closer to the database. For availability purposes minimal number of
connection pool pods is 2, ideally they have to be distributed between
different nodes/AZ, but it's not enforced in the operator itself. Available
configuration supposed to be ergonomic and in the normal case require minimum
changes to a manifest to enable connection pool. To have more control over the
configuration and functionality on the pool side one can customize the
corresponding docker image.
Co-authored-by: Felix Kunde <felix-kunde@gmx.de>
* define postgres-pod clusterrole and align rbac in chart
* align UI chart rbac with operator and update doc
* operator RBAC needs podsecuritypolicy to grant it to postgres-pod
* add CRD manifests with validation
* update documentation
* patroni slots is not an array but a nested hash map
* make deps call tools
* cover validation in docs and export it in crds.go
* add toggle to disable creation of CRD validation and document it
* use templated service account also for CRD-configured helm deployment
* align config map, operator config, helm chart values and templates
* follow helm chart conventions also in CRD templates
* split up values files and add comments
* avoid yaml confusion in postgres manifests
* bump spilo version and use example for logical_backup_s3_bucket
* add ConfigTarget switch to values
Dmitry Dolgov
Felix Kunde