Ubuntu

Ubuntu is a glibc and apt based distribution. The ubuntu image is a minimal root filesystem with fewer packages than a normal install.

Documentation: Ubuntu Server docs Project: Ubuntu · Docker Hub

See also Container Distros, Debian and Dockerfile.

apt in Dockerfiles #

COMMAND	DESCRIPTION
`apt-get update`	Refresh indexes; always in the same `RUN` as the install
`apt-get install -y --no-install-recommends PACKAGE`	Install without recommended extras
`rm -rf /var/lib/apt/lists/*`	Remove the indexes at the end of the layer
`apt-get purge -y --auto-remove PACKAGE`	Remove a package and its unused dependencies
`apt-cache policy PACKAGE`	Installed and candidate versions
`apt-get install -y PACKAGE=VERSION`	Pin a version
`dpkg -L PACKAGE`	List a package’s files
`dpkg -S /PATH/TO/FILE`	Which package owns a file

dockerfile
FROM ubuntu:24.04
RUN apt-get update \
 && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
      ca-certificates curl tzdata \
 && rm -rf /var/lib/apt/lists/*

Use apt-get rather than apt in scripts: apt is meant for interactive use. Setting DEBIAN_FRONTEND on the RUN line keeps it out of the final image environment.

Image Tags #

TAG	MEANING
`ubuntu:24.04`	LTS release by number (preferred)
`ubuntu:noble`	The same release by codename
`ubuntu:latest`	Latest LTS; avoid in builds
`ubuntu:rolling`	Latest release including non-LTS (unverified)

Users #

COMMAND	DESCRIPTION
`useradd -r -u 10001 -m APP`	Create a system user with a fixed UID and a home directory
`groupadd -r GROUP`	Create a system group
`id ubuntu`	The 24.04 image already contains an `ubuntu` user (UID 1000), so `USER ubuntu` works

CA Certificates and Timezone #

COMMAND	DESCRIPTION
`apt-get install -y --no-install-recommends ca-certificates`	Needed for HTTPS from a minimal image
`update-ca-certificates`	Rebuild after adding `.crt` files to `/usr/local/share/ca-certificates/`
`apt-get install -y --no-install-recommends tzdata`	Install zone data
`ln -fs /usr/share/zoneinfo/Europe/London /etc/localtime && dpkg-reconfigure -f noninteractive tzdata`	Set the timezone without a prompt
`-e TZ=Europe/London`	Alternative at `docker run` (needs `tzdata`; unverified)

Gotchas #

SYMPTOM	FIX
Build hangs on a `tzdata` or keyboard prompt	Set `DEBIAN_FRONTEND=noninteractive` for that `RUN`
`E: Unable to locate package`	Run `apt-get update` in the same `RUN` (the image ships without indexes)
`curl: (60) SSL certificate problem`	Install `ca-certificates`
Image grows after installs	Remove `/var/lib/apt/lists/*` in the same layer
No `sudo`, `ps`, `ping` and similar	Minimal image; install the package that provides it
Sources are in `/etc/apt/sources.list.d/ubuntu.sources`	24.04 uses the deb822 format, not `sources.list`