A mechanical elephant

A mechanical elephant

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.

Keep talking

Keep talking

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.

Build your own aggregate

Build your own aggregate

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.

Nobody expects the spanish inquisition

Nobody expects the spanish inquisition

An ancient italian proverb says Il backup è quella cosa che andava fatta prima. A rough translation could be something like this: the backup is the thing that had to be done before. The concept of backup is quite confusing. Some people wrongly believe that executing a local backup is sufficient to ensure the recover of the data. In the real world a valid backup is present only if three conditions are true.