In the previous post we modified the apt role for controlling the setup in a declarative way. Then we added a ssh role for configuring the three devuan servers. The role is used to configure the server’s postgres process owner for ssh passwordless connection.
In this tutorial we’ll complete the setup for the postgres user and then we’ll configure the database clusters with a new role.
In the previous post we configured three devuan servers from scratch using ansible adding the pgdg repository to the apt sources and installing the PostgreSQL binaries.
This tutorial will revisit the apt role’s configuration and will introduce a new role for configuring the postgres operating system’s user for passwordless ssh connections to each other server.
The ansible is a fictional device invented by Ursula K. Le Guin. The ansible allows fast communication between two points across the space, regardless of the distance.
It doesn’t surprise that the Red Hat’s ansible shares the same name as it gives a simple and efficient way to manage servers and automate tasks, yet remaining very lightweight with minimal requirements on the target machines.
Before the release of pg_chameleon 2.0 I had to write an upgrade procedure to allow a smooth migration from the version 1.8.
An interesting challenge I faced was to determine the maximum and minimum position for the MySQL’s binary logs belonging to the same server but stored with different values in multiple sources.
The user defined aggregates, a feature pretty unique to PostgreSQL, allowed me to solve the problem in a robust and simple way.
