[BlueOnyx:17991] Re: 5209R (CentOS 7.1)

[Michael Stauber]

Hi Tom,

> After the official release of 5209R (CentOS 7.1), will there be any plans 
> for a 5209R (Scientific Linux 7.x) release? Or is it included in the 
> download of 5209R?
> I assume there is not much difference.

I haven't decided yet, but I'm leaning towards saying: Not in the near
future. In reality there is no longer a compelling reason to prefer SL
over CentOS. Since the CentOS team has teamed up with RedHat they are
naturally faster with updates than any other third party could be. The
SL maintainers still do a stellar job, though. But they're rolling a
rock uphill there and I don't envy them for that position.

> I also read on the Blueonyx website that the preferred install
> was the SL/BO version over the CentOS/BO version.

Yeah, that used to be our position and it was suitable for the time when
it was initially written. As you might recall: The CentOS developers had
really been slacking off at or around the time EL6 came out and they
needed a lot of time to get their heads screwed on tight again.

While that happened the wording on our OS recommendation page changed a
few times as we gradually adjusted our position to reflect the ongoing
development of the situation.

As for the 5209R ISO image: It is the culmination of several hundreds of
hours of work. That's no kidding or exaggeration. Getting it to the near
perfect state where it currently is was a tremendous amount of work. I
pretty much had to start over from scratch as 98% of my ISO-building
routines that I had carried over from EL6 wouldn't work with EL7.

With every OS update (such as from 7.0 to the current 7.1) I need to go
"back to the basics" and need to build a customize Anaconda and need to
fiddle with fundamentals to get it to build the ISO correctly again.

Likewise: Just the build and test environment for the ISO's for 5207R,
5208R and 5209R ISOs takes up more than half a terabyte on my local
workstation. The build architecture for the older ISO's? That around
800GB that I currently archived to storage.

I once wrote an article in the devel-blog about ISO building for
CentOS7, which you can find here:

http://www.blueonyx.it/index.php?mact=News,cntnt01,detail,0&cntnt01articleid=182&cntnt01returnid=54

There are more rants about ISO building in the devel blog. Usually when
they (again) broke something upstream that would mess with ISO building.
In fact: It happened so often for no good reason that I'm now fully
convinced they do it to prevent any kind of forks or that part of the
show is run by some sadistic bastards. :p

To be able to build the 7.1 ISO using my trusted and tested 7.0
mechanisms? That took another 3-4 days of trial and error and chasing
obscure Anaconda error messages in heavily convoluted Python code. Every
test run (build ISO, transfer to file-server, do a test install in a VM)
takes two hours. Even if you just changed one line of code somewhere in
the installer. Each new ISO release requires about 2-3 days of fiddling
and testing for every individual ISO. Even if it builds fine first time
around - only after installing it at least once in every supported boot
option will tell the whole story.

Let us look at the 5207R/5208R situation: That's 4 ISOs for two Linux
distributions and their two flavors. I will need to occasionally build
updated ISOs for them as well - until the EOL of EL6 in 2020.

If I provide 5209R ISOs for both CentOS 7 and SL7, then I'd need to
maintain six ISO images in total if we include 5207R/5208R. It would be
seven ISO's if I were still building 5106R ISO's, which I actually won't
do anymore. It would be 11 ISO's if I'd still build ISOs for 5106R,
5107R and 5108R, too.

If I'd really do all of that, I'd need to lock myself into a closet for
a month and doing nothing but ISO building. Just to be able to do it.

So ... I'd rather not (at this time) build an 5209R SL based ISO. There
simply isn't a compelling reason that would justify this tremendous
extra effort. That position might eventually change. It's not carved in
stone. But even then: My recommendation would be to choose CentOS 7 over
SL 7.

Other than that: If you really wanted to give 5209R on SL a try: We
streamlined the manual install procedure so much, that it's now rather
trivial to do. Just follow the instructions on this page:

http://www.blueonyx.it/index.php?page=5209r-manual-install

Of course another option is this one: Install using the existing 5209R
ISO and then switch out the RPM centos-release for sl-release from the
SL mirrors. That would tie your box into the SL mirrors instead of using
the CentOS mirrors for updates.

-- 
With best regards

Michael Stauber