podman¶

docker, podman, buildah... 👋

see also docker

working with pods¶

create a new pod¶

…which can hold multiple containers (they can then communicate between each other via localhost and exposed ports):

podman pod create --name lab # without any exposed ports to the host
podman pod create --name lab -p 127.0.0.1:3001:3001 # expose ports to the host

list pods¶

podman pod list

add containers to a pod¶

adding the uptime-kuma container and cloudflared to the pod. The cloudflared tunnel can then be configured as a proxy to proxy requests to localhost:3001 to expose the uptime-kuma container to the web (the whole network exposing thing couldn't be required)

podman run -dt --restart=unless-stopped --pod lab -v uptime-kuma:/app/data --name uptime-kuma louislam/uptime-kuma:1
podman run -dt --restart=unless-stopped --pod lab cloudflare/cloudflared:latest tunnel --no-autoupdate run --token <asdf-token>

working with containers¶

list all podman containers, including build containers¶

I was used to get all running and exited containers with docker's docker ps -a, however, podman has another place to list containers. Containers started by buildah, to build containers. Here's how to list them:

podman ps --all --storage

update container¶

pull the new image, stop and delete the old container, re-run the command how you initially started the container to get it back up.

podman inspect my-container --format "{{.Image}} {{.ImageName}}"
podman pull username/container:latest
podman stop my-container
podman rm my-container
podman run -dt --restart=unless-stopped --pod lab --name my-container username/container:latest
podman inspect my-container --format "{{.Image}} {{.ImageName}}"

cleanup old / unused containers and images¶

apparently that's what I do. Coming from Docker, the whole buildah containers thing are quite confusing

just do it like this:

podman system prune

get rid of images:

podman rmi $(podman images -a|grep none|awk {'print $3'})

unmount all images:

podman unmount --all

for more detailed things, and also the build images/containers do this:

podman rm $(podman ps --all -q) # regular containers
podman rm $(podman ps --all --storage -q) # buildah containers

generate systemd / kubernetes definitions¶

podman generate --help

generate a kubernetes yaml file from an existing container/pod:

podman generate kube my-pod

run kubernetes definition using podman:

podman play kube my-pod.yaml

if, let's say, after a reboot you get something along the lines pod already exists, you can replace the deployment:

podman play kube my-pod.yaml --replace