A NethServer system is constituted by RPMs that come mainly from CentOS, EPEL and NethServer mirrors. Updates are announced by each project on its specific channel:

A NethServer machine fetches:

  • NethServer updates from an URL like:$releasever/updates/$basearch/
  • CentOS updates from an URL like:$releasever/updates/$basearch/
  • EPEL updates from an URL like:$basearch

Where $releasever is currently 7, and $basearch is x86_64.

All those packages updates improve the original system release by pushing it forward, like rolling continuously.

When CentOS produces a new minor version like 7.5.1804 they publish a new “minimal” ISO image. The NethServer developers add a small RPM set on that image together with a kickstart file. The resulting image is the NethServer ISO, with installer, server-manager and other stuff.

When NethServer 7.5.1804 is released, any existing 7.4.1708 installation can be upgraded seamlessly, because both CentOS and NethServer ensure compatibility between minor releases.

Locking to a specific distribution release

It is possible to lock to a specific distribution release, like 7.5.1804 as explained in the “Software center” section of the administrator’s manual.

The implementation is provided by the nethserver-base package and is based on the following elements:

  • sysconfig/NsReleaseLock prop
  • software-repos-save event
  • software-repos-upgrade event