What distribution is most used in production environment

RedHat, CentOS, Debian, Ubuntu.

All are good choices.

Well, maybe not Redhat these days...
- Red hat with UBI-Micro still mostly deployed after alpine in enterprise and mission critical server, so let us see if it' dwindling in next 3-5 years ahead.

Ubuntu, RedHat, AWS Linux, Arch. Honestly distros in production are pretty similar since they're all headless and pretty pared-down. If you just know the logistics of a few package managers and init systems you'll be good.

I'm surprised to see arch on your list, I know everything runs in containers now but arch seems way too unstable O_o

By unstable I don't mean "buggy", but "you will have to adapt to new major version of package XXX or you can't fetch updates anymore, so no security patches anymore".
- I never ran into this so I don’t really know what you’re talking about

Debian.

I once worked in for a small publishing company years ago, circa 2005, where they used CentOS on the desktop and server environments. Deploying a new desktop was as simple as using kickstart. They had their infrastructure down to a science.

I hope I can get my company to go linux. But for now I can only use it for myself. But i'm quietly pushing :)
- Good luck, users at my company would flip out if the desktop wallpaper was unfamiliar.

I'd suggest RedHat and SUSE as well.

To tag onto this, what makes RHEL so special? Is it just the support you get from Red Hat or is there something about the distro that makes it so widely used?

Support contracts for risk mitigation is a big part of it, and the other is RH release engineering is amazing.

Aside from that, RHEL, and clones, is a very straight forward, clean distro. It’s very focused with everything doted and tidy, and overall, it has a very uncomplicated feel to it. In contrast Debian derivatives are kind of messy, and SUSE tries to stuff every function into a single application.

RHEL does push a lot of technology. Out of the stable distros, it will be the first to put tech into production. RH does a lot with integration with other systems. This has kept me off of SUSE in the past. RHEL was more tech forward, comparatively.
- dnf downgrade
  
  dnf history undo
  
  dnf history redo
  
  it's very very very critical for most case :')
It is 100% the support. Corporations pay big money to have experts on call to fix things fast when they break, and there's basically no other player for that kind of model in the Linux space.
- Debian could stand against it, if https://www.debian.org/consultants/ and https://wiki.debian.org/LTS/Extended consolidated, sadly for now, it isn't, and I don't see any project go towards it.

Depends on context.

If you want to get a job as a "Linux admin" then Red Hat is basically what you want as a "default". Fedora will give you something you can use at home that's broadly similar. You will need to learn more than just that though.

Using Fedora at home because you have to use Red Hat at work? NOPE, thanks. Also I wonder if that RHEL focus is mostly american companies? Because here in europe I rarely see RHEL used from my limited perspective.

Mostly mission critical server that I deployed in the past, all use RHEL/Clones because their LTS, and stability across packages version.

If for hobbyist, it's Ubuntu. I think you need to learn more about ansible, container/podman/openshift, and SDN for work. Nowdays, there are some use APT in production, but mostly they switch to dnf because dnf have better way to do downgrade, undo, redo, and config package in production.

This applied mostly for ERP project such as SAP Hanna, SQL Server, DB2, etc... Like it not, Red Hat Dwindling isn't now, probably 5-10 years ahead, but I'm not sure, as mostly rant about RHEL are in Community. I do know regional linux user group in Indonesia, some are leaving EL group, but they still can't rip apart most mission critical server on top of RHEL/Clones... so it's still worth learning RHEL/Clones, and use Fedora for day 2 day task, and learn ubuntu, as well ubuntu pro, for learn deploying critical production server.

Debian and Ubuntu are near, and ubuntu is derived from debian, but if you talk spirit, they are different... If you are conscious about what Red Hat do, stay away from it, but if you are working in corporate, you can't go without learning it.

Fun fact. At Heineken Netherlands we also happen to use SAP. the backend is using SLES-11 how ever
- Well SLES is quite lean near RHEL, they have same rpm/dnf pkg manager, which is near RHEL, but not B2B compatible, or even ABI compatible, but SUSE is okayish, but I don't know, many corporate that work for aren't keen using it haha.. 😂
  
  Well at least, seems Europe have different kind of market, but having competitor is driving industry forward isn't it?
  
  Well SAP is from German, but I don't know why it's much for popular on top of RHEL, rather than other. I do know Ubuntu support SAP, but never seen one in the wild in Asia Pasific. 😂
  
  Also I remember IBM Watson is on top SLES? 😂😂 Dunno if IBM replace it with Red Hat? Haha.. 😂

All of my personal servers are Debian. My last company switched their entire production fleet from centos to Debian. I think a lot of people switched to Debian back when the Centos Stream debacle went down.

Company I'm at runs Windows server. Kill me.

Oh dear god

It really depends. I work for a large company and we use Ubuntu, Oracle, RedHat, and SLES. We were moving from Oracle to Ubuntu but now we are going back to RedHat.

Currently we deploy like this: Ubuntu: PostgreSQL, web servers, some engineering workstations, and big data Oracle & RedHat: web servers, security applications, and network systems

So just having a fundamental understanding of Linux and you will be fine SUSE: SAP and HR software

What's the reason if I may ask why they are moving to Red Hat instead?
- Mostly cost. We used to run a lot of Oracle databases and they have become extremely expensive to keep running. So we are migrating to PostgreSQL. The servers were getting migrated to CentOS but now that RedHat fucked that distro we are going back to RedHat. Part of that deal is switching from chef to Ansible. So to save costs we are consolidating to a single vendor.

Where I'm at, that would be Ubuntu, followed by Debian.

I've been seeing a lot of alpine based containers recently. Used to see a lot of Ubuntu, debian, redhat.

I think a lot of it depends on if you are spinning a lot of containers up.

I work for a well known internet company, and its 98% redhat (or derivative) with some alpine and ubuntu scattered about randomly

If you want to learn more than one distro, try setting up Docker containers for various services. The base distros in the containers use the same commands as on the base metal

I work at NASA and we use redhat a lot for development work.

100% sure its Debian.

Mission critical server mostly are RHEL or EL Clone or Fedora or it's derivative... If you combine even Azure nowdays, Microsoft Linux is derived from Fedora, same as Amazon Linux, and others... Debian are covering some part, but mostly hobbyist, or SME, and mostly non critical, as they don't have standard across, even on their https://wiki.debian.org/LTS/Extended and https://www.debian.org/consultants/

apt also bad when you got to dowgrade package when something mess up, and get messy with dpkg.. :'(

So I quite doubt if it's production env, mostly go with EL. I do know some company use Ubuntu/Debian, but it's quite few...

If Ubuntu/Debian want to shape Industries, and kick out RHEL, they need to have standard, and better consultancy than RHEL. I hope so that they could grow and make market competitive, but for now it isn't sadly.

ime: red hat & centos dominate with ubuntu, debian, suse and amazon linux all a distant 2nd.

i also expect it to change given red hat's recent decision to stop sharing their source.

Not Linux but there are still a of Unix System V systems out there too. AIX, Solaris and HP-UX. Harder to learn as very much not open source software (although there is the Illumos project with distros like OpenIndiana).

Nobody said Alpine? Youre debugging k8s containers your gonna find Alpine, Ubuntu/Debian and CentOS.

Once you know package managers and basic images you're gonna be able to get what you need.

A lot of my clients were using CentOS. Not sure what'll happen next now that Red Hat killed CentOD.

I've seen some organisations move from CentOS to Rocky Linux.

My experience in my career has been all RHEL/CentOS. The meat of Linux admin isn't going to hugely change between most distros tho. Different package mgmt, how the network is configured, etc... Spin up an VM, install it from scratch, and just learn those differences.

Ive worked a couple fortune 500s that used ubuntu. If im using aws ill stick with their distro but most of time im happy with ubuntu. I think distro choice matters less and less. Most of the systems ive run recently have had ansible to configure them or have just run docker containers. Most of the gov contracts iveworked on insisted on red hat but honestly the teams making those decsions seemed the least technically capeable ive worked with and it was just a red tape issue to change distros

I think in fortune 500, it's only fraction that use ubuntu/Debian, as most of marketshare hold by red hat, 95% as I remember last time. Than 3% of windows, less than that is everything else.

Started with RHEL years ago, migrated to CentOS to get away from the license fees etc. Have since moved to Amazon Linux since we subsequently migrated everything to AWS.

I always use Ubuntu Server. It was my first distro 20 years ago and it's still where I'm most comfortable.

I work at a big company: most of our customers are using RHEL when they use Linux. There are some customers that use SUSE for SAP workloads, but these are about 10% of all linux VMs.

The default Linux image on AWS (Amazon Linux) is RPM-based; but the default image on Google Cloud currently appears to be Debian "bullseye" (the April 2023 release) with an option for "bookworm" (brand new this month). I'm not sure about Microsoft Azure but their docs suggest a Debian default as well.

So that's one impression. Knowing both dpkg/apt and rpm will serve you well.

Major tech companies have their own internal distributions in their production datacenters, which focus much more on their specific needs. Any major tech company using Linux in datacenters will have an engineering team specifically building what they need.

That's interesting to know thanks! I do know some dpkg and apt but nothing about rpm so will learn more about that.
Agreed; I was going to comment something similar: I work with SAP (SAP's HANA database runs on SUSE). When I need a free swrver OS for anything else, I go debian (I used RH from 4.2 to 8.0 when they fooled us once, then went debian).

So being comfortable with a rpm based and a deb based system is good advice.

On the server side, when most administration is through ssh, distro differences are not as relevant as for GUI environments. Package handling is the most impacting difference (and I prefer deb), not that it's a showstopper, when you have yast and aptitude though.

i dont get why people do not just use debian. especially if they got their own it person / support

No certification and no support. Critical bug will be fixed faster in RHEL than Debian when come to Enterprise, very clear structure and powerful consultancy.

Debian consultancy never near RHEL, that's why they need to work hard on that, and make industry standard.

Red Hat drive the industry standard for more than 20 years... That make every Corp lean to it, and it won't dwindling soon.. Unless other are making Debian standardized.

Ubuntu tried it, still not even taking chunk I guess? Mostly Enterprise is RHEL/Clones.
- No certification and no support. Critical bug will be fixed faster in RHEL than Debian when come to Enterprise, very clear structure and powerful consultancy.
  
  that is just corp talk for "it is not my problem"
  
  I dont know ubuntu server, which i mostly use because of livepatch, with unattended upgrades seem to fare better than the rhel deploys that i have done - and the customer never updated. Granted the last is not enterprise but Uni bioinfo servers but still.
Personal take: RHEL is a very high quality well integrated OS. Debian is a mess of community opinion all conflicting held together by outdated and poor tooling.
- i find both rhel and debian tooling very outdated to be honest.

Almost always use Ubuntu in production. Also a bit of Centos at one point.

My current job is all Ubuntu LTS, my job before that was all CentOS, and my job before that was a mixture of Debian and FreeBSD.

So basically your resume goes backwards... ;)

Most likely debian or debian-distroless

I work for a big enterprise, we have RHEL on all our Linux servers save for a few that are SuSe for SAP.

I'm seeing a lot of very interesting answers but I'm wondering what you mean by "production environment".

Do you mean VFX Production? (English not my first language so if "production" is used in different industries, well, I didn't know).

I'm new to the industry and worked for small companies that don't use Linux. But my VFX peeps use Rocky, Mint, and Ubuntu ( stronger preference for Rocky in studios).

In IT in the US, "production" is commonly used to refer to systems that support actual business operations. In other words, it's as opposed to "development" or "testing" systems.
- Thanks! So I gather the default is IT and not VFX, fair enough. It makes sense.
In this context production means servers or machines which make money in a business. The partner term is normally staging: a testbed environment.

I was working as a DWDM technician sometime ago and IIRC most of DWDM hardware (or at least the Infinera ones, as I had used those the most) were actually running on Gentoo, which was kinda surprising for me.

But in "regular" environments I have mainly seen Ubuntu or Debian.

Mostly cost. We used to run a lot of Oracle databases and they have become extremely expensive to keep running. So we are migrating to PostgreSQL. The servers were getting migrated to CentOS but now that RedHat fucked that distro we are going back to RedHat. Part of that deal is switching from chef to Ansible. So to save costs we are consolidating to a single vendor.

So what are the biggest differences. Or is it mostly the same? Also thanks for the responses!

Most Linux distros are more alike than different. They'll use different package managers, have different sets of software available, have different default settings for some stuff, but at the end of the day, Linux is Linux. Once you know enough, the distro is almost meaningless in terms of what you're capable of. You can do almost anything on any distro with the right knowledge and a bit of effort. It mostly becomes about the effort at that point.

Skills you learn on one will be 98% transferrable to another. That's why everybody says to just get Red Hat certifications; not because Red Hat has a monopoly, but because their certification process is fantastic, respected and accepted almost anywhere regardless of what they actually run. As you've seen, almost every answer you got was completely different on what they actually run in production.

The only standout differences are the newish trend of immutable distros (openSUSE ALP/Aeon, Fedora Kinoite/Silver blue, etc) and NixOS, which is also immutable but its own beast entirely. These have some new considerations separate from the rest, especially NixOS. But they're still relatively fresh on the scene, so there's no rush to learn about them just yet.

For learning system administration, I think Cent OS Stream can be a great choice. Not because it offers something special than others but because it would familiarize you with the RHEL/Fedora family and in my experience majority of enterprise-servers are using one of its family members, be it RHEL, the former CentOS, Oracle Linux, Amazon Linux or some other variant.

anyone using nixOS?

For production server? No. mostly NixOS is for desktop.

Ansible cover what nixOS doesn't in Debian/RHEL space, and it's idempotent and better than nixOS config. Unless they change their approach for server, I don't see any way in near future it will be massively adopted.

At work: Alpine-based docker containers. Flatcar Container Linux for host VMs.

Personally: Ubuntu Server. Some alpine docker containers.

At this point? Probably Cent OS, since that's what AWS uses. It's a variation of Ubuntu. So if you don't count it as separate, then definitely Ubuntu.

CentOS is an RHEL variant, not Ubuntu.
Are you sure you mean centos? Centos is a rolling release of the next version of rhel.