CentOS - Feb 2021 - Transition test report going from CentOS8 to Debian 10.

Sorry for the length....


I'm posting this here since this particular transition has been 
mentioned on-list as one possibility for a path forward for current 
CentOS Linux users.? AlmaLinux, the Developer Subscription RHEL, Rocky, 
CentOS Stream, Springdale, upgrading to full RHEL; all these are also 
possibilities, too, and all have different strengths and weaknesses.? 
The transition to Debian has a lot of strengths, including a long 
track-record of support (even if the support time for a particular 
release is shorter), a fully-open development model with no 'corporate 
overlord' that I know of, a large set of supported packages, and a huge 
community of developers and users.? For the CentOS user the main 
weakness is having to learn a few areas of difference in the way the 
system is setup and maintained; of course, if a ten-year 'stable' 
timeframe is really that important to you the lack of that is also a 
weakness.


So, last week I transitioned, as a test of sorts, my working CentOS 8 
main laptop to Debian 10.? I kept a complete backup of the C8 install 
should I wish to go back to it, and installed Buster to a new mSATA SSD, 
but ported the two SATA drives (Dell Precision M6700 - has an mSATA slot 
plus two SATA bays) straight over after making full backups.


I posted a pretty complete rundown on the scientific linux users mailing 
list, so I won't recap it all here.? The bottom line was the the 
transition was not any more difficult, really, than moving from CentOS 7 
to CentOS 8.? The software versions in Buster are pretty close to what 
is in CentOS 8, although I have yet to need any third-party repository 
(PPA) for anything I've needed to install.


All the packages I have worked with so far have worked fine with a 
little bit of massaging.? These include commercial (and costly) software 
such as Harrison Consoles' Mixbus32C, Qoppa's PDFStudio2019 
Professional, and others.

So if you were to decide that this is the route for you to take, it does 
work and I found it to be not nearly as hard as I had thought it might 
be.? If you install GNOME 3 you get GNOME 3; it feels pretty much the 
same as a non-Classic CentOS GNOME 3, just with a different set of 
extensions installed by default.

That's on the workstation.

On the server side, I'm evaluating Proxmox for the virtualization 
solution, and so far I'm finding it to be a pretty easy migration.? I'm 
using the 'non-subscription' repository, so this is a no-cost option.? 
Even getting the box registered to our EMC Clariion SAN was relatively 
easy; EMC provides the Unisphere Server Utility for Linux x64 in RPM 
form; the latest I have is 
"ServerUtil-Linux-64-x86-en_US-1.0.55.1.0044-1.x86_64.rpm" (which is 
fairly old, but I did say Clariion arrays, so they're pretty old, too).? 
Debian has provided the 'alien' tool for some time; after installing 
alien, a simple 'alien -i 
ServerUtil-Linux-64-x86-en_US-1.0.55.1.0044-1.x86_64.rpm' installed the 
EMC RPM in the correct place.? Proxmox already included everything that 
serverutilcli requires; on a plain Buster install I had to install 
dm-multipath and the device mapper libraries and tools before 
serverutilcli would find the arrays; but it ran just like it did on 
CentOS 8 (and 7).

I haven't decided whether to stay on Debian or not; too early to tell.? 
I have time to test and evaluate.? My CentOS 7 installs aren't goin 
anywhere, though, at least until late 2023.? And I've registered for a 
Developer subscription of RHEL so that I can properly evaluate that 
option, too.

This is the beauty of open source: we have OPTIONS.

On 2/4/21 9:39 AM, Lamar Owen wrote:
> Sorry for the length....
> 
> 
> I'm posting this here since this particular transition has been 
> mentioned on-list as one possibility for a path forward for current 
> CentOS Linux users.? AlmaLinux, the Developer Subscription RHEL, Rocky, 
> CentOS Stream, Springdale, upgrading to full RHEL; all these are also 
> possibilities, too, and all have different strengths and weaknesses. The 
> transition to Debian has a lot of strengths, including a long 
> track-record of support (even if the support time for a particular 
> release is shorter), a fully-open development model with no 'corporate 
> overlord' that I know of, a large set of supported packages, and a huge
> community of developers and users.? For the CentOS user the main 
> weakness is having to learn a few areas of difference in the way the 
> system is setup and maintained; of course, if a ten-year 'stable' 
> timeframe is really that important to you the lack of that is also a 
> weakness.
> 
Thank you, Lamar, for your post. I second what you said about strengths. 
I converted a few machines to Debian myself (number cruncher that is wen 
server and samba file server simultaneously, and a couple of 
workstations). Oh, I forgot this: laptop I set up for my wife quite a 
wile ago also runs Debian. I would add one thing (some may consider it 
extra strength, others may think otherwise). Debian doesn't make any 
decisions for you, so you really have to do your own thinking and 
decide, say, which firewall to install. And choices are plentiful.

And as Lamar said, you will have some learning curve with which commands 
to use, several will be different commands from what usually are in rpm 
based distro. But that is minor thing IMHO.

And while they tolerate it, I will once again mention: Consider FreeBSD 
(or any of BSD descendants) for servers. Once you are there, you will 
never regret that. I do not.

Thanks again, Lamar, for detailed and very encouraging post!

Valeri
> 
> So, last week I transitioned, as a test of sorts, my working CentOS 8 
> main laptop to Debian 10.? I kept a complete backup of the C8 install 
> should I wish to go back to it, and installed Buster to a new mSATA SSD, 
> but ported the two SATA drives (Dell Precision M6700 - has an mSATA slot 
> plus two SATA bays) straight over after making full backups.
> 
> 
> I posted a pretty complete rundown on the scientific linux users mailing 
> list, so I won't recap it all here.? The bottom line was the the 
> transition was not any more difficult, really, than moving from CentOS 7 
> to CentOS 8.? The software versions in Buster are pretty close to what 
> is in CentOS 8, although I have yet to need any third-party repository 
> (PPA) for anything I've needed to install.
> 
> 
> All the packages I have worked with so far have worked fine with a 
> little bit of massaging.? These include commercial (and costly) software 
> such as Harrison Consoles' Mixbus32C, Qoppa's PDFStudio2019 
> Professional, and others.
> 
> So if you were to decide that this is the route for you to take, it does 
> work and I found it to be not nearly as hard as I had thought it might 
> be.? If you install GNOME 3 you get GNOME 3; it feels pretty much the 
> same as a non-Classic CentOS GNOME 3, just with a different set of 
> extensions installed by default.
> 
> That's on the workstation.
> 
> On the server side, I'm evaluating Proxmox for the virtualization 
> solution, and so far I'm finding it to be a pretty easy migration.?
I'm
> using the 'non-subscription' repository, so this is a no-cost
option.
> Even getting the box registered to our EMC Clariion SAN was relatively 
> easy; EMC provides the Unisphere Server Utility for Linux x64 in RPM 
> form; the latest I have is 
> "ServerUtil-Linux-64-x86-en_US-1.0.55.1.0044-1.x86_64.rpm" (which
is
> fairly old, but I did say Clariion arrays, so they're pretty old, too).
> Debian has provided the 'alien' tool for some time; after
installing
> alien, a simple 'alien -i 
> ServerUtil-Linux-64-x86-en_US-1.0.55.1.0044-1.x86_64.rpm' installed the
> EMC RPM in the correct place.? Proxmox already included everything that 
> serverutilcli requires; on a plain Buster install I had to install 
> dm-multipath and the device mapper libraries and tools before 
> serverutilcli would find the arrays; but it ran just like it did on 
> CentOS 8 (and 7).
> 
> I haven't decided whether to stay on Debian or not; too early to tell.
I
> have time to test and evaluate.? My CentOS 7 installs aren't goin 
> anywhere, though, at least until late 2023.? And I've registered for a 
> Developer subscription of RHEL so that I can properly evaluate that 
> option, too.
> 
> This is the beauty of open source: we have OPTIONS.
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
-- 
++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
++++++++++++++++++++++++++++++++++++++++

On Feb 4, 2021, at 8:39 AM, Lamar Owen <lowen at pari.edu>
wrote:
> 
> I posted a pretty complete rundown on the scientific linux users mailing
list, so I won't recap it all here.
Link?
> the transition was not any more difficult, really, than moving from CentOS
7 to CentOS 8.
That?s not my experience.

I keep several of my packages running on CentOS and Debian (and more) and I keep
running into several common problems:

1. The package names are often different, and not always differing by an obvious
translation rule.  For instance, it?s ?openldap-devel? on CentOS but
?libldap2-dev? on Debian, where the normal rule would make it ?libopenldap-dev?.
Why the difference?  Dunno, but I have to track such things down when setting up
scripts that do cross-distro builds.  If I automate that translation, now I?m
setting myself up for a future breakage when the package names change again. 
(libldap3-dev?)

2. Some packages simply won?t be available.  Most often this happens in the
Debian ? CentOS direction, but I?ve run into cases going the other way.  Just
for one, I currently have to install NPM from source on Debian because the
platform version won?t work properly with the platform version of Node, last
time I tested it.  Why?  Same answer as above.

3. Debian adopted systemd, but it didn?t adopt the rest of the Red Hat userland
tooling.  For instance, it?s firewalld on CentOS, UFW on Ubuntu, and raw kernel
firewall manipulation on Debian unless you install one of those two.  And then,
which?

4. Network configuration is almost entirely different unless you turn off all
the automation on all platforms, in which case you might as well switch to macOS
or FreeBSD for all the good your muscle memory and training will do you.

I?m not saying ?don?t do it,? but to say it?s as smooth as from CentOS 7 to 8? 
Hard sell.

I?ll give you one mulligan: the changes to the security rules in CentOS 8 caused
a huge upheaval for one of my applications, since it basically stopped it from
running, being naughty in Red Hat?s omnisciently beneficent eyes.  We spent
about a year fixing breakages due to 25 years of built-up assumptions about what
was correct and sensible, which don?t affect us on other Linuxes because they
didn?t implement the same SELinux rules.

The details aren?t super-important, because the real take-away is this: it?s
always *something.*

(For those that must know, the biggie was that our systemd-based service used to
run from /home/$APPNAME but that?s a no-no on C8 now.  Moving it all under
/opt/$APPNAME and rearranging it all according to LFS rules, then finding and
fixing all the places we depended on such paths was *painful*.)

On 2/4/21 10:39 AM, Lamar Owen wrote:
> ...
> I haven't decided whether to stay on Debian or not; too early to 
> tell.? ..... 
Six months on, and no longer too early to tell.? I have found Debian to 
be minimally different from CentOS, in all actuality; much less 
different than transitioning to a *BSD would be.? I've transitioned 
already deployed and configured production CentOS 8 machines to either 
Alma or Rocky (path of least resistance), keeping CentOS 7 machines on 7 
until I need to revisit in 2023, and CentOS 6 machines went to Debian 
10.? Now, I'm going to say that the availability of both Rocky and Alma 
is a very good thing, and that availability made things a lot easier for 
a few already deployed production systems that needed to stay stable 
through the end of the year.

New servers are being deployed on Debian 10; new virtualization hosts on 
Proxmox 6.4, although I am testing the Proxmox 6 to 7 upgrade path at 
one site and on my development hosts at the main site.? Proxmox is 
SLICK.? The upgrade path for simple servers from Debian 10 to Debian 11 
is relatively simple, with a few caveats (no python 2.x in 11, so no 
Mailman 2.x, for instance).? I have upgraded a few development servers 
from 10 to 11, and no issues were noted.

Your mileage may vary, of course, but I've had a reasonably good 
experience with this transition.?? Thought I'd never say that; I've been
a Red Hat user (partisan, even) for a very long time.