Another era has come, when our Debian 10 (Buster) server has also reached its peak, and it has become a pressing task to do something about this problem. In this article, we will upgrade a perfect Debian 10 (Buster) server to Debian 11 (Bullseye system). On this page, we will review the basic system, as well as our higher-level server services, and perform the necessary post-configurations. The article has been updated with fixes for network interface (systemd) bugs encountered in Debian 11, as well as new GPG key management (signed-by) settings for external repositories (e.g. Sury PHP).

By making the web and other services running on our server available to the public, there may be a need for a comprehensive monitoring system that allows us to track information about the utilization of various resources on our server from one place. Many of these softwares are available today, on this page we review the handling and use of Munin plugins.