Docker🔗

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Important Commands

docker pull $image # pull image from registry
docker ps # list containers
docker container ls # list (running) containers
docker run -d -it $image_name # start persistent container
docker exec -it $container_id /bin/bash # get a shell

Images🔗

Using an image checksum in the definition can be used to verify integrity and downloading a modified container.²

Publish image as GitHub Package

Installation🔗

Debian from apt repo

Rootless🔗

https://docs.docker.com/engine/security/rootless/

creates a new context
running root and rootless Docker concurrently shouldn’t be a problem anymore, but the context might have to be specified, as the rootless setup makes rootless Docker default¹

Keep user containers alive after logout

sudo loginctl enable-linger $(id -u)
export DOCKER_HOST=unix:///run/user/$(id -u)/docker.sock
export XDG_RUNTIME_DIR=/run/user/$(id -u)
systemctl --user status docker.service
# if still dead try
systemctl --user restart docker.service

^4d425a

Disadvantages and Limitations🔗

https://docs.docker.com/engine/security/rootless/#known-limitations

https://linuxhandbook.com/rootless-docker/
Using Slirp4netns mode solves this problem, and shows the original address of the request. But it also has two problems.

IPv6 not supported.
speed is much slower (about 7Gbps).

openSUSE🔗

newuidmap and newgidmap already available, package uidmap doesn’t exist
installed fuse-overlayfs as recommended
Docker package from distro repos didn’t have script dockerd-rootless-setuptool.sh, so I am trying to install a package provided by Docker
run (see openSUSE forum)

sudo zypper install docker rootlesskit
sudo systemctl --now disable docker.service
curl -fsSL https://get.docker.com/rootless | sh
systemctl --user --now enable docker.service

The openSUSE package rootlesskit doesn’t include all the scripts other repo’s packages provide.

Glossary🔗

Term	Description	Similar	Example
image
registry	place to store images	harbor
context	like an environment (incl. endpoint)		docs

References🔗

How to Assign a Static IP to a Docker Container