Why I am not enthused about Red Hat Enterprise 6

January 11, 2014

I have to admit straight off the bat that this is mostly an uninformed prejudice. I have not actually run RHEL 6 machines (our few RHEL machines are RHEL 5); all that I've ever done with it is install it a couple of times to test some things. So part of this is based on general knowledge of what it has and part of this is based on those install experiences.

My impression of the install experience was not positive. Although I don't remember details, it struck me as generally less functional and more annoying than the RHEL 5 equivalent. I could make it work but I didn't like it. And of course the capstone of the install experience is that it uses NetworkManager (in a situation that NM is not good for) and then leaves your networks down when you boot the installed system. This means that the very first post-install thing we'd have to do with RHEL 6 is to reconfigure all the networking, ripping NM out and putting the old ways back in.

Beyond that, RHEL 6 is simply built on an awkwardly transitional base because it was done at a bad time. It's based on Fedora 12 plus chunks of 13 and 14, which puts it just before Fedora made a number of important changes such as moving from upstart to systemd, a major change in hotplug device handling, and so on. You get some changes from the old ways of RHEL 5 but they are by and large the wrong changes, ones that would later be abandoned. And you get other changes that were only half-baked at the time of Fedora 12, such as NetworkManager (especially on servers). All of this leaves me unenthused.

We are not big RHEL users here, so my general plan (to the extent that I had any) was to skip RHEL 6 entirely and wait for RHEL 7 for, say, new iSCSI backends. Various things have gone wrong with that, but that's another entry.

Comments on this page:

We do all our RHEL builds with Cobbler, using a fairly minimal Kickstart based on the included default, and have had comparatively few post-install problems (although more build time issues with e.g. BIOS device names). Certainly NM hasn't cropped up. Overall, EL6 is a lot nicer to work on than 5, if only because the EPEL packages tend to be more up to date.

By John at 2014-01-11 12:10:04:

We are using RHEL6 extensively, including to serve iSCSI via tgtd and it has been rock solid. RHEL6 is much nicer to work with than RHEL5. Boot times are much faster. RHEL6 plus EPEL has been fine for us, though of course it's at the end of the cycle now so packages are fairly dated. We don't use NM. We use puppet to provision.

We are looking forward to RHEL7 and plan to standardize on it.

Before RHEL we were FreeBSD which I left reluctantly but it was a wise move.

From at 2014-01-12 06:07:29:

Networkmanager is nice for laptops. Except when you want to run kvm for testing purpuses, because NM does not play nicely with bridged networking.

For servers, not so much. All it takes is adding NM_CONTROLLED="no" to the ifcfg-interface file to disable it. We disable the networkmanager daemon as well, all using cfengine. Not a problem, really. We have lots of centos 6 servers and this is not a problem at all.

Solving those problems are just a minor annoyance and a part of a major version upgrade of the OS. So if you move from rhel 5 to rhel 6, the time you invest solving this will be spread during 10 years (centos 6 was release in november 2010 and will get updates until 2020, following rhel schedule).

On another note, Fedora 12 was a brilliant release, so it was a wise move to base rhel 6 on that one.

Written on 11 January 2014.
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Last modified: Sat Jan 11 03:48:03 2014
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