Docker
Migrating zabbix from mysql to timescaledb - migration
This series describes how to migrate a mysql database to timescaledb - use case is to migrate a zabbix application database. This part handles the migration and switchover of the server environment up to completion of the migration.
Rocketchat fails after upgrade with index error
Upgrading rocketchat to version 5.0 resulted in some minor issues that prevented the system from starting - both are related to the database and can easily be fixed.
upgrade postgres with timescaledb
Upgrading postgres can be a challenging task, because databases are mostly in use. Having extensions like timescaledb introduces even more complexity. This guide shows a fast way to upgrade a postgres database with timescaledb.

Migrating zabbix from mysql to timescaledb - setting up environment
This series covers migrating a zabbix database from mysql to timescaledb. In this post we're preparing the databases for the migration.

docker swarm - preserve client ip on incoming connections
Running services in docker swarm utilizes the docker swarm routing mesh which results in source nat (snat). If you need to bypass this, check out this guide.

docker daemon not starting after upgrade
Having upgraded docker you may come into a situation where the docker daemon itself doesn't start anymore because of an issue with firewalld.

Docker - Hardening with firewalld
Containers are no virtual machines - yet we might want to treat hosts running container workloads like hypervisors and apply limitations on container networking. This guide describes a way to limit container networking on docker based container hosts using firewalld.