my scratchpad

command / prompt	description
/var/lib/docker	where are docker containers stored
docker exec -it <container_name> sh	open a shell into a running container (more)
docker image ls	list all docker images
docker image rm	removes an image from the host node — alias `docker rmi`
docker rmi $(docker images -a -q)	remove all locally installed Docker images
docker image prune	removes all dangling images (those with tag none). The `-a` option would also remove images that have no container
docker ps -a	list all containers, including the stopped ones — alias: `docker container ls -(l)a`
docker container prune	remove stopped containers
docker logs	container_id can be either the name or the identifier of the container. You can also use `-f` to follow
systemctl status docker	check the status of the docker deamon
pgrep docker	find the PID of the docker deamon

some docker cheatsheets

Aichbauer v4 (provenance)

how to build the docker image and run the container for IACS'24'COGN

cd into the /iacs-ui.24.cognitera/frontend directory so that you have the Dockerfile in the current directory
Make sure the user is in the docker group (see the entry below)
build the docker image with the --network host option and supply a plausible name:
```
$ docker build --network host -t iacs-ui.24.cogn:v1 .
```
if you want to keep and perhaps examine the logs of the docker build process use the following in lieu of the above command:
```
docker build --no-cache --progress=plain --network host -t iacs-ui.24.cogn:v1 . 2>&1 | tee docker-build.log
```
run the image by mapping port 8080 to its 8000 port (alternatively use the -P option), pass an environment variables file into the container and also supply a short reasonable name for the container (e.g. iacs in the incantation below):
```
$ docker run -d -p 8090:8000 --env-file=.env --name iacs iacs-ui.24.cogn:v1
```
verify the ports the web application being hosted inside the container is listening on:
```
$ docker port iacs
8000/tcp -> 0.0.0.0:8080
8000/tcp -> [::]:8080
```
connect your browser to localhost:8080
to "ssh" (sort of) into the container you cannot use docker attach but you must instead use docker exec as follows (see this SO answer for more):
```
docker exec -it iacs sh
```
once you are done, stop the container using docker stop iacs — there's no need to do docker container prune to remove the stopped container as the image was run with the -d option in step 4

permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock

provenance
The user that is running the docker commands (if he is a non-root user) must be added in the docker group. This is done with the following incantation:

sudo usermode -aG docker $USER

newgrp docker

docker

[Errno 101] Network is unreachable

In November 2024 when going through this docker beginners tutorial (also saved here) I encountered this trace:

In the end I had to change the docker build invocation from:

docker build . -t mperdikeas/catnip

docker build . --network host -t mperdikeas/catnip

In initially commented on an already existing bug report and then reported my solution here.

The solution was found in this thread which also reports at least one additional approach.