There are many ways to run high availability with PostgreSQL; here we present a template for you to create your own custom fit high availability solution using etcd and python for maximum accessibility.
Compose runs a a Postgresql as a service platform, which is highly-available from creation. This is a coded example from our prior blog post: High Availability for PostgreSQL, Batteries Not Included.
To get started, do the following from different terminals:
> etcd --data-dir=data/etcd
> ./governor.py postgres.yml
From there, you will see a high-availability cluster start up. Test different settings in the YAML files to see how behavior changes. Kill some of the different components to see how the system behaves.
Add more postgres*.yml files to create an even larger cluster.
For a diagram of the high availability decision loop, see the included a PDF: postgres-ha.pdf
Run the following on a Mac to install requirements:
brew install postgresql etcd haproxy libyaml python
pip install psycopg2 pyyaml
There are many different ways to do HA with PostgreSQL, see the PostgreSQL documentation for a complete list.
We call this project a "template" because it is far from a one-size fits all, or a plug-and-play replication system. It will have it's own caveats. Use wisely.