HA based on Stolon
Stolon is a cloud native PostgreSQL managerfor PostgreSQL high availability. It’s cloud native because it’ll let you keep an high available PostgreSQL inside your containers (kubernetes integration) but also on every other kind of infrastructure (cloud IaaS, old style infrastructures etc…)
- Leverages PostgreSQL streaming replication.
- Resilient to any kind of partitioning. While trying to keep the maximum availability, it prefers
consistency over availability.
- Kubernetes integration letting you achieve postgreSQL high availability.
- Uses a cluster store like etcd or consul as an high available data store and for leader election.
- Asynchronous (default) and synchronous replication.
- Full cluster setup in minutes.
- Easy cluster admininistration
- Can do point in time recovery integrating with your preferred backup/restore tool.
- Standby cluster (for multi site replication and near zero downtime migration).
- Automatic service discovery and dynamic reconfiguration (handles postgres and stolon processes
changing their addresses).
- Can use pg_rewind for fast instance resyncronization with current master.
Stolon is composed of 3 main components:
- keeper: it manages a PostgreSQL instance converging to the clusterview provided by the sentinel(s).
- sentinel: it discovers and monitors keepers and calculates the optimal clusterview.
- proxy: the client’s access point. It enforce connections to the right PostgreSQL master and forcibly closes connections to old masters.
Stolon is under active development and used in different environments. Probably its on disk format (store hierarchy and key contents) will change in future to support new features. If a breaking change is needed it’ll be documented in the release notes and an upgrade path will be provided.
Anyway it’s quite easy to reset a cluster from scratch keeping the current master instance working and without losing any data.