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Distributions

A distribution packages the Linux kernel with a userland, a package manager, defaults and a support lifecycle. Server work mostly happens on two families, Red Hat and Debian, so commands on this site are shown for both.

Track: Core · Interview weight: Low

Must-Know Facts

Fact Value Verify with
Red Hat family RHEL, Rocky, AlmaLinux, CentOS Stream, Fedora, Amazon Linux grep ID_LIKE /etc/os-release
Debian family Debian, Ubuntu, Linux Mint grep ID_LIKE /etc/os-release
Package formats .rpm with dnf; .deb with apt rpm --version, dpkg --version
CentOS Stream Upstream of RHEL since 2021, not a rebuild cat /etc/redhat-release
RHEL rebuilds Rocky Linux and AlmaLinux grep ^ID= /etc/os-release
Ubuntu LTS Every two years in April (YY.04), 5 years standard support lsb_release -a
RHEL support 10 years per major release grep SUPPORT_END /etc/os-release
Container minimal images Alpine (musl, BusyBox), distroless, UBI cat /etc/os-release in the image
Architecture names x86_64 = amd64; aarch64 = arm64 uname -m, dpkg --print-architecture

Families

Family Distributions Package tools Typical use
Red Hat RHEL, Rocky, AlmaLinux, CentOS Stream, Fedora, Amazon Linux rpm, dnf Enterprise servers, RHCSA
Debian Debian, Ubuntu, Mint dpkg, apt Cloud images, CI runners, desktops
SUSE SLES, openSUSE rpm, zypper SAP and European enterprises
Arch Arch Linux, Manjaro pacman Rolling desktops
Independent Alpine apk Small container images

The full list of active distributions is tracked at the LWN distributions list.

Release Models

Model Meaning Example
Fixed release, long support Versions frozen; fixes backported for years RHEL, Rocky, Ubuntu LTS, Debian stable
Upstream preview Continuous stream ahead of the next fixed release CentOS Stream, Fedora
Rolling No major versions; packages update continuously Arch, openSUSE Tumbleweed

CentOS Linux 7 and 8 are end of life

CentOS Linux 8 ended in December 2021 and CentOS 7 in June 2024. Servers still running them receive no fixes; Rocky Linux and AlmaLinux are the usual migration targets.

Identifying a Distribution in Scripts

grep -E '^(SUPPORT_END|ROCKY_SUPPORT_PRODUCT)=' /etc/os-release
rpm --eval '%{rhel} %{_arch}'

Output:

SUPPORT_END="2035-05-31"
ROCKY_SUPPORT_PRODUCT="Rocky-Linux-10"
10 x86_64

dpkg --print-architecture
uname -m

Output:

amd64
x86_64

Debian says amd64 where the kernel says x86_64

Debian packages name the architecture amd64; the kernel calls it x86_64. Download URLs for tools such as kubectl use one or the other, and mixing them is a common cause of 404 in install scripts.

Interview Checkpoints

L1: What is the difference between RHEL, CentOS Stream and Rocky Linux?

Say first: CentOS Stream is the development stream that the next RHEL minor release is cut from; RHEL is the supported product; Rocky and AlmaLinux rebuild RHEL for free.

Proof: cat /etc/redhat-release on each.

Follow-up: What changed for CentOS users in 2021?

L1: Why choose an LTS or enterprise release for servers?

Say first: fixed package versions with backported security fixes keep behavior stable for years, which matters more on servers than new features.

Proof: grep SUPPORT_END /etc/os-release shows the end of support.

Follow-up: What is the cost of that stability? (Older language runtimes and tools.)

L1: Why are many container images based on Alpine?

Say first: Alpine is a few megabytes because it uses musl and BusyBox, which shrinks pull time and attack surface.

Proof: docker images alpine versus ubuntu.

Follow-up: What breaks when moving a glibc-built binary into Alpine?

L2: A script must download the right binary for the machine. Which architecture name does it use?

Say first: read it from the system and map it to the vendor's naming.

Proof:

case "$(uname -m)" in x86_64) arch=amd64 ;; aarch64) arch=arm64 ;; esac
echo "$arch"

Follow-up: Where does Debian report the same value directly? (dpkg --print-architecture.)

L2: How do you find when a server's distribution stops receiving updates?

Say first: read SUPPORT_END or the vendor lifecycle page.

Proof: grep SUPPORT_END /etc/os-release; hostnamectl prints "OS Support End" when the file sets that field.

Follow-up: What is the plan for a host that is past that date?

L3: An install script works on Ubuntu but fails on Amazon Linux 2.

Say first: check the family and package manager before the script's logic.

Proof: grep -E '^(ID|ID_LIKE)=' /etc/os-release shows ID_LIKE="centos rhel fedora", so apt calls fail.

Follow-up: How should the script detect the family?

Captured on Rocky Linux 10.2 and Ubuntu 24.04.4 LTS (iximiuz Labs microVMs, kernel 6.1.167), 2026-09.