stolon

stolon is a cloud native PostgreSQL manager for 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...)

Architecture

Stolon is composed of 3 main components

  • keeper: it manages a PostgreSQL instance converging to the clusterview computed by the leader sentinel.
  • sentinel: it discovers and monitors keepers and proxies and computes the optimal clusterview.
  • proxy: the client's access point. It enforce connections to the right PostgreSQL master and forcibly closes connections to old masters.

architecture_small

Installation

Stolon is available in brew. It is unofficial and not supported by the project.
So check the version before installing using brew.

Step to install using brew

Project Status

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.

Requirements

  • PostgreSQL 12, 11, 10 or 9 (9.4, 9.5, 9.6)

  • etcd2 >= v2.0, etcd3 >= v3.0, consul >= v0.6 or kubernetes >= 1.8 (based on the store you're going to use)

  • OS: currently stolon is tested on GNU/Linux (with reports of people using it also on Solaris, *BSD and Darwin)

build

To build stolon we usually test and support the latest two major versions of Go like in the Go release policy.

make

High availability

Stolon tries to be resilient to any partitioning problem. The cluster view is computed by the leader sentinel and is useful to avoid data loss (one example over all avoid that old dead masters coming back are elected as the new master).

There can be tons of different partitioning cases. The primary ones are covered (and in future more will be added) by various integration tests