
Docker dropping support for RHEL/CentOS6.x - visualphoenix
https://github.com/docker/docker/issues/14365
======
chomp
OpenStack dropped support for CentOS 6 in its Kilo release, so this isn't too
surprising.

CentOS 6 was released in 2011, which is 4 years old. A lot of features Docker
uses have been highly improved since the 2.6 days, so it makes sense to drop
support for operating systems which don't support some things.

~~~
harlowja
Correction, openstack dropped python 2.6 support in its kilo release, you can
of course run python 2.7 on centos6.x/rhel6.x (and I know companies doing
this, including godaddy and yahoo) via a variety of manners, and then
openstack will work for you again (until u can shift to centos7.x or rhel7.x).

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mcescalante
For anyone else curious, Docker 1.8's target release date is August 4th, so
basically in a month all support will be dropped for RHEL/Centos 6.x.
Definitely a bit concerning to me.

I'm quite interested to see how the whole Open Container Project pans out, and
I'm pleased by the prospect of it, just hoping they successfully iron out some
of the "Docker wrinkles" that have shown over the course of it's lifecycle in
the last few years. No 6.x support from the get go doesn't necessarily put a
great taste in my mouth, so far.

~~~
visualphoenix
Super worrying to me too. 1.8 marked the move to Open Container Project. I
guess this means Open Container Project won't be supporting 6.x.

It would have been nice to get more than 1 month of notice.

~~~
niels_olson
Interesting sidelight: DoD uses RHEL almost exclusively, so this sort of
implies that DoD has no interest in Docker as their container of choice.

Edit: to clarify, I was thinking the HPC systems are RHEL, and account for a
fairly large number of RHEL licenses. Certainly the "enterprise" is outlook,
sharepoint, and a ton of Win7 terminals.

~~~
greyboy
Interesting. All the DoD systems we interface with run Windows. There may be a
mixture, we just don't work with those systems.

~~~
niels_olson
Valid point. I guess I was thinking the HPC systems. Certainly every client-
facing terminal is a Windows box. I don't know much about the network stack,
but there's clearly a lot of Windows there too.

~~~
greyboy
We're an external partner pulling data via a 24/7 Windows-based web service, a
system of record. The three we work with are all Windows, but three is likely
a blip in their system count.

All I know is it's weird how they and their vendors manage the systems and
environments. Glad it isn't me!

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jareds
I use cent OS 6.6 on a server because it is similar to the software our
customers run. I also like using docker even though our customers do not. At
this point I'm just going to install ubuntu server and use Vagrant so I can
run what ever OS I need.

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sysk
I have a very limited understanding of how distributions work so this is
probably a stupid question but why don't RHEL/CentOS update the Linux kernel
they ship with their 6.x OS? Isn't the kernel supposed to never break user
space apps?

~~~
WestCoastJustin
RHEL focuses on stability over bleeding edge features. What this typically
means is that you will have an older kernel / user land packages installed,
then Redhat backports security patches into it's maintained ports. You can
read about it here [1]. The end result is a fairly stable kernel and system
OS. But, you have to live with an older feature set (think 2-3+ year old
package with just security patches applied).

I've maintained lots of RHEL boxes as a sysadmin -- here's my take. This type
of release cycle works pretty well, in that you can almost always apply
patches without hosing your system due to "new features". One example of
something this protects you against, is a package changing the expected config
file format, or maybe the expected command line arguments. Another good
example, would be a change to a kernel driver for some storage array, or
network interface, that could quickly break lots of systems!

This type of release cycle also gives commercial software vendors a known
target to develop against and sell support for. Say for example, that you are
using an enterprise database like Oracle/Sybase/DB2, they will verify their
product works against RHEL 5.x/6.x/7.x and give you commercial support, as
they have a pretty good understanding of what you are running. But, if the
kernel/packages are always moving targets, it would be near impossible to
support your end platform, so this also adds to the backporting of security
patches without adding features thought process.

Although, it is also a pain, in that you are typically way behind on cool
things happening out there on other distros. So, there are pros and cons to
it. But, if you are running a large mission critical DB cluster, you typically
want things to be extremely stable, so for the target market (the enterprise)
this works pretty well.

[1]
[https://access.redhat.com/security/updates/backporting](https://access.redhat.com/security/updates/backporting)

~~~
jsmeaton
There are definitely upsides and downsides. The vast majority of our systems
are RHEL6, because that's what a vendor of ours supports. Since we have the
infrastructure around to support RHEL6 (puppet modules, vm templates etc),
most of our supporting systems are also RHEL6.

If we need newer features or packages, we spin up a CentOS7 or RHEL7 image
which still isn't bleeding edge, but is significantly newer than RHEL6.

It's nice to have a bit of stability for apps and services that require it -
but there's always the option of bringing newer versions online for the
services that need it.

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JupiterMoon
I guess that Red Hat will have to keep supporting it with security updates
then?

~~~
nickstinemates
As per their support model for 6.x, but, in the description:

RedHat themselves only support Docker on RHEL7 (as stated by
[https://access.redhat.com/solutions/1378023](https://access.redhat.com/solutions/1378023),
and confirmed by several people)

~~~
visualphoenix
Right but this is odd considering they used to support it and only quietly
updated their support document in May. If a fellow issue commenter on github
hadn't linked to it I (and everyone else) would have missed it.

~~~
nickstinemates
I don't know what they've said when publicly, but the intention of 6.x on
their end related to support for Docker has always been best efforts in terms
of their support practices. Docker support by Red Hat in RHEL7 is actually a
compelling differentiation they use in the field to get their existing
customer base to upgrade.

This conversation goes back to the moment we started talking about it before
the announcement[1] in September 2013

1: [http://www.redhat.com/en/about/press-releases/red-hat-and-
do...](http://www.redhat.com/en/about/press-releases/red-hat-and-dotcloud-
collaborate-on-docker-to-bring-next-generation-linux-container-enhancements-
to-openshift)

------
ams6110
I don't know why they ever bothered.

People running RHEL are among the most conservative Linux users there are. We
have some of that where I work. We have big production systems still running
RHEL 5 (which RedHat still supports, and for those systems the less you change
the less of your time they demand).

Anyone still using RHEL 6 is not really the sort of person who jumps onto the
latest container or cloud frameworks the moment they are released. If they are
into virtualization at all, they are probably using VMWare.

~~~
nodesocket
I have to argue with your point a bit. I actually prefer RHEL (CentOS) and if
given a choice, I still run CentOS. It is what I started with, and now am most
familiar with, but agree the package versions are super old and outdated. I do
like yum more than apt, but probably again because it is was I'm most familiar
with.

~~~
uxp
I agree. I'm more DevOps, (really, just a dev that is super comfortable in an
ops position) and my go-to distro has always been Debian, but nearly every
position I've had has been supporting applications on Ubuntu. It wasn't until
my last position when we were acquired and thrown into a CentOS ESXi
datacenter that I really started to love CentOS's release cycle. You won't get
all the somewhat recent or cool features without feeling like you're treading
into the territory of hacks and warranty-voiding (try running Xen on Cent or
RHEL), but you'll also not dread keeping your servers up to date, or keeping
on top of the latest logoed vulnerability sweeping the net. I'd guess that 99%
of the standard LAMP and at least 80% of the common Rails, SQL, K/V almost-
crud apps could benefit from CentOS.

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X-Istence
I am not surprised. RHEL 6 is getting long in the tooth!

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armab
That's strange. CentOS 6.x is still very popular.

~~~
FooBarWidget
And shipping with kernel 2.6 and being 4 years old.

~~~
x5n1
yeah it makes sense the 2.6 kernel is too ancient. They have kept it patched
up, but upward and onward!

