In-Place Upgrades

For LTS systems, continuity during upgrades is a factor that seems secondary at first glance. Many companies have synchronized the life cycle of their hardware with the software, so that a gradual transition is the rule after the typical five years when the old hardware is out of warranty. In addition to purchasing new hardware, admins will also immediately complete the OS upgrade.

Basically, the cycle works well if you are well prepared. If a company wants to update before the hardware warranty expires, however, the approach has restrictions. Ubuntu supports an update between LTS versions out the box, and Red Hat also had an equivalent function. It was always cumbersome, somewhat buggy, and often did more harm than good. RHEL 7 aims to fix this: A dedicated "In-place upgrade wizard" facilitates the ugprade from RHEL 6 to 7.

The prerequisite for this feature is that the admin previously used RHEL 6.5. Only then is a corresponding package available; it gives you an overview of the process. Along with details of which changes will happen automatically, the report also lists changes that admins have to do themselves.

Local Install Media

Red Hat has set a stiff target for competitors to beat in terms of deployment automation: Anaconda and Kickstart are generally viewed as robust and highly functional tools. In RHEL 7, you can also use them to create a modified boot medium for installing the system. Instead of using the standard medium, you then build your own custom installation CD or USB stick.

The modified settings are immediately deployed on new systems after installation in the local setup. Basically, the function is a middle ground between bare-metal deployment tools like Cobbler [7], Foreman [8], and Chef [9] and manual configuration after the install. The advantage of modified installation media is obvious: Admins can use their own setups without needing to install a separate service for the purpose.

Red Hat Enterprise Linux 7 is the first version of RHEL officially to use the successor to the legacy SysV init system: systemd. Very few other software components have caused so much fuss in the FLOSS community since their inception. All distributions also agree basically that the old SysV init system looks very outdated and needs to be replaced by a contemporary tool.

Ubuntu and Red Hat originally moved forward with different approaches: Ubuntu's Upstart was finished quickly and made its way into Ubuntu 12.04 more than two years ago. Red Hat wanted to replace the init system with a central hub for system administration  – that is, a control center that centrally manages important services and parameters. The implementation, systemd, has now found its way into RHEL via different versions of Fedora.

First Enterprise Distribution with systemd

RHEL 7 is the first enterprise release to include systemd [10], a modern replacement for the classic init daemon-starting daemon. Systemd is already standard on many community-based Linux distros, and the migration into the enterprise space seems inevitable. Ubuntu patron Mark Shuttleworth recently announced an end to Ubuntu's work on Upstart as an init alternative, opting instead for systemd as the new standard in future versions of Ubuntu. SUSE will also turn to systemd with SLES 12.