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-=-=-=-=-=-=-
:author:
mcgillij
:category:
Linux
:date:
2021-08-31 22:49
:tags:
Linux, Containers, Podman, Docker, docker-compose, #100DaysToOffload
:slug:
podman-compose
:summary:
How to switch over to Podman for all your Docker and *docker-compose* needs.
:cover_image:
podman.png
The current Docker eco-system is a flaming dumpsterfire. With all the current downtime, changes to
(clamping down on people doing CI / CD using images from their repositories) and limiting the amount of auth’d and un’authed pulls you can do definitely broke a bunch of companies builds for several days last year.
[image: Current DockerHub status]
Current DockerHub statusNow with today’s
that they are going to a subscription model for their “previously” free tool is likely the final straw for many folks.
I’ve been toying with
for a bit, and more recently I’ve migrated several of my self-hosted things to
which is a drop-in replacement for *docker-compose*.
Well I’m sure if you’re really interested you can read more about it on their site. However it’s essentially an unprivileged docker replacement (that can run in user namespaces) aka rootless.
It can be used a drop in replacement for most *Dockerfiles* to build them. All the commands are similar to their *docker* counterparts. Even their documentation page recommends just to create an alias below.
alias docker=podman
However I didn’t go that far, just removed *docker* from my system and now I’m just using *podman* commands.
If you’ve ever used **docker-compose** well it’s the exact same thing as that, except it can use **podman** behind the scenes. Even capable of parsing **docker-compose.yml** files directly. Allowing you to stand up entire stacks of containers with just a single command.
So setting up podman requires a bit of configuration to get working as a **docker** replacement. However as long as your comfortable editing a couple configuration files, it’s super easy.
First install **podman** with your distributions package manager. I was installing it on my server which is running
so I ran the following:
apt-get update && apt-get install podman
This is all that’s required to get **podman** installed. Onto the configuration.
Now to get the same functionality (ie: pulling containers from dockerhub), you will need to edit a couple configurations.
In **/etc/containers/registries.conf** add the following line:
unqualified-search-registries=["docker.io"]
And also in **/etc/containers/registries.conf.d/shortnames.conf** you can add some of your favorite container shortnames.
I’ve added the containers below to the shortnames.conf, but you can add whichever you figure you’ll be using.
"postgres" = "docker.io/library/postgres" "pihole" = "docker.io/pihole/pihole"
That’s it, now you should be able to use **podman run** with most of the containers on dockerhub. Now you are setup for running single containers, we’ll cover running stacks below with **podman-compose**.
Since **podman-compose** like *docker-compose* is written in
you’ll need to install it with either pip, pipenv or poetry (whichever python package manager your using).
Example with pip:
pip install podman-compose
Example with poetry:
poetry add podman-compose
Etc…
Once you have it available you can try running the *podman-compose* command to make sure it’s working as intended, you should see some similar output to the below:
![[image: Current DockerHub status]](/kennedy.gemi.dev/archive/cached?url=gemini%3a%2f%2fgemini.mcgillij.dev%2fimages%2fdumpsterfire.gif&t=638427227780000000&raw=False){kind=link}
usage: podman-compose [-h] [-f FILE] [-p PROJECT_NAME] [--podman-path PODMAN_PATH] [--no-ansi] [--no-cleanup] [--dry-run]
[-t {1pod,1podfw,hostnet,cntnet,publishall,identity}]
{pull,push,build,up,down,run,start,stop,restart} ...
optional arguments:
-h, --help show this help message and exit
-f FILE, --file FILE Specify an alternate compose file (default: docker-compose.yml)
-p PROJECT_NAME, --project-name PROJECT_NAME
Specify an alternate project name (default: directory name)
--podman-path PODMAN_PATH
Specify an alternate path to podman (default: use location in $PATH variable)
--no-ansi Do not print ANSI control characters
--no-cleanup Do not stop and remove existing pod & containers
--dry-run No action; perform a simulation of commands
-t {1pod,1podfw,hostnet,cntnet,publishall,identity}, --transform_policy {1pod,1podfw,hostnet,cntnet,publishall,identity}
how to translate docker compose to podman [1pod|hostnet|accurate]
command:
{pull,push,build,up,down,run,start,stop,restart}
pull pull stack images
push push stack images
build build stack images
up Create and start the entire stack or some of its services
down tear down entire stack
run create a container similar to a service to run a one-off command
start start specific services
stop stop specific services
restart restart specific services
The output looks very similar to the other command.
Now you may have a couple *docker-compose.yml* files for some of your applications running on your server kicking around (I know I do), and you want to migrate them over to using *podman-compose*.
We’ll take a peek ag my
file, and see about getting it up and running with podman.
version: '3'
services:
plex:
image: plexinc/pms-docker
restart: unless-stopped
environment:
- TZ=AST
network_mode: host
volumes:
- /home/j/plex/config:/config
- /tmp:/transcode
- /home/j/plex/library:/data
Nothing looking out of the ordinary, this YML file works in both docker-compose and podman-compose. You can even use the same parameters for the most part.
Running the following will bring up my Plex server.
podman-compose up -d
You will get some output, keep an eye out to make sure everything working properly.
Now you should be able to check on your running containers with the **podman ps** command.
$ podman ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 6933f433a0a3 ghcr.io/linuxserver/airsonic:latest 43 minutes ago Up 43 minutes ago airsonic_airsonic_1 655586a457c3 docker.io/plexinc/pms-docker:latest 40 minutes ago Up 40 minutes ago plex_plex_1 b7ca4551181c ghcr.io/linuxserver/medusa:latest 38 minutes ago Up 38 minutes ago pymedusa_medusa_1
You can also use the **logs** parameter similar to with the docker command to inspect things further.
podman logs 655586a457c3 ... Plex Media Server first run setup complete [cont-init.d] 40-plex-first-run: exited 0. [cont-init.d] 45-plex-hw-transcode-and-connected-tuner: executing... [cont-init.d] 45-plex-hw-transcode-and-connected-tuner: exited 0. [cont-init.d] 50-plex-update: executing... [cont-init.d] 50-plex-update: exited 0. [cont-init.d] done. [services.d] starting services [services.d] done. Starting Plex Media Server.
If you are used to running the following:
docker-compose ps # OR docker-compose exec # OR docker-compose logs
You will need to use the regular *podman* command to inspect / run things or see the logs as it’s not covered by **podman-compose**. Which is a really small price to pay. All the functionality is still accessible, but you just have to type less, so it’s win win.
Also being **rootless** means, that you can’t bind to ports under 1024 normally as your regular user. However if you **really** want to. You can issue the following command:
sudo sysctl -w net.ipv4.ip_unprivileged_port_start=<NUMBER>
Replace **NUMBER** with whatever the lowest port number you want unprivileged users to be able to use.
With how terrible the docker eco-system is getting, it’s nice to have a drop-in replacement, that’s actually better and more secure. Even being compatible with the **.yml** files with compose is a nice cherry on top.