Setup up a Linux instance to act as a podman server allowing you to run
podman-compose commands remotely.
So for example you can develop on a Mac, but run containers via podman and podman-compose at least some of the time.
This article will show you how to:
Setup a remote
podmanserver (RHEL, Fedora, CentOS - Ubuntu should just be package changes)
Setup podman remote client on your Mac (Should work for Windows and Linux too)
For an increasing number of reasons lately I’ve been defaulting to podman more and more on my Mac though I still also have
docker installed and use both day to day.
I’m not going to go into the pros and cons of both in this article but there are some resources at the end of this article.
Setting up podman remote client has been covered before, for example Podman remote clients for macOS and Windows and in the repo’s Podman remote-client tutorial itself however I found a couple of gotchas hence this article. The goal is for this to be a comprehensive HOWTO. which should work if followed on both x86 and M1 Macs.
Linux host e.g. a home-lab machine or Linux VM
Pretty much any Mac, M1 or x86 (the instructions below should work with few changes for Windows or another Linux client if you have a use case)
Part 1: Setting up your Podman Host
So recently I built a powerful home-lab machine to run Fedora and planned to use it to learn KVM better and run VMs.
In my case, and this is way overkill for typical needs, I built an 8 core AMD Ryzen 3800 based system with a generous with 128GB RAM, and a 1GB M2 drive.
Currently it runs Fedora 34 and Podman
This article should work fine with far more modest configurations.
Enable podman daemon to listen for remote request
setup ssh keys - careful here, it’s a little fussy
Add the remote podman service to the Mac
Install and Enable
Assumptions: You already have a running fedora (RHEL, CentOS, etc should work fine), with
sshd already configured.
podmanand the optional compose components
fedora $ sudo dnf install -y podman docker-compose podman-compose
Enable and start the service for your user by enabling the
fedora $ systemctl --user --now enable podman.socket
Keep the socket alive with
lingerwill ensure the
podmanservice is always available irrespective of whether you are logged in or not
fedora $ sudo loginctl enable-linger $USER
podman.socket is listening
There are a number of ways we can confirm the socket is now listening.
Easiest is to query with
fedora $ systemctl status podman.socket
● podman.socket - Podman API Socket Loaded: loaded (/usr/lib/systemd/system/podman.socket; enabled; vendor preset: disabled) Active: active (listening) since Sat 2021-05-29 07:01:11 EDT; 1 day 3h ago Triggers: ● podman.service Docs: man:podman-system-service(1) Listen: /run/podman/podman.sock (Stream) CGroup: /system.slice/podman.socket
You can also simply
fedora $ curl --unix-socket /run/user/1000/podman/podman.sock http://localhost/_ping
The path above contains your User ID
/run/user/<USER_ID>/…which you can obtain with
idRemember this as you’ll need during the setup section on your Mac.
Setup ssh authentication on your Mac
This was the part that initially caught me out.
I’d been using RSA keys for years so I initially tried it with my
This was also how I had seen examples both in the docs and in at least one blog article.
Turns out at some point, I’m assuming relatively recently, support for RSA keys has either been dropped in favor of the more recent, and secure, ed25519 keys or I simply caught a bug/issue.
Certainly there were other users caught by this.
Reading through closed Issues in the Podman Repo it may be that RSA keys do now again work. Testing this is an exercise for the reader, and hey ed25519 keys are stronger!
|This section is performed on your Mac. (should also work on a Windows/Linux host)|
Generate your ed25519 key if you don’t already have one
mac $ ssh-keygen -t ed25519 -C "firstname.lastname@example.org"
Copy your new key from your Mac to your podman host, in my case
mac $ ssh-copy-id -i ~/.ssh/id_ed25519 fedora
Validate by ssh’ing to your podman machine explicitly using the new key
mac $ ssh tok@fedora -i ~/.ssh/id_ed25519
Last login: Sun May 30 09:40:05 2021 from 192.168.1.54 fedora $
Part 2: Connect to the
Setting up your Mac. I’m a sort of latest and greatest person so today this is running on the latest Big Sur
11.4 and I mix an older MBP 16” with a new MacBook Air M1 which is an awesome portable rocket ship. Despite using Ansible for most things lets keep this simple:
Install podman on your Mac
mac $ brew install podmanNote
I’m assuming your
PATHis setup correctly
/usr/local/binon x86 and
/opt/homebrew/binon the M1. Incidentally it’s worth noting if you are installing on an M1 based system that it is actually an ARM based package:
Add the remote
mac $ podman system connection add development --identity ~/.ssh/id_ed25519 ssh://homelab/run/user/1000/podman/podman.sockNote
developmentin the above command should be a meaningful name for your remote system as you can have multiple remote podman services
Remember you need your remote User ID which if you’ve forgotten can easily be retrieved eg:
ssh tok@fedora -i ~/.ssh/id_ed25519 id
uid=1000(tok) gid=1000(tok) groups=1000(tok),36(kvm) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
Test your system
Now you should be able to access and use
podman from your Mac
List the podman system connection services
mac $ podman system connection list
Name Identity URI development* /Users/tok/.ssh/id_ed25519 ssh://tok@fedora:22/run/user/1000/podman/podman.sock production /Users/tok/.ssh/id_ed25519 ssh://tok@production:22/run/user/1000/podman/podman.sockTip
Here there are 2 remote systems which can both be used, including our new
developmentservice we just created. To set the default, here
development, on your Mac:
podman system connection default development
Now test from your Mac
mac $ podman system info | head
host: arch: amd64 buildahVersion: 1.20.1 cgroupManager: systemd cgroupVersion: v2 conmon: package: conmon-2.0.27-2.fc34.x86_64 path: /usr/bin/conmon version: 'conmon version 2.0.27, commit: ' cpus: 16
Launch your first image, let’s use
alpinesince it’s nice and small
mac $ podman run -it --rm docker.io/alpine sh
Trying to pull docker.io/library/alpine:latest... Getting image source signatures Copying blob sha256:540db60ca9383eac9e418f78490994d0af424aab7bf6d0e47ac8ed4e2e9bcbba Copying config sha256:6dbb9cc54074106d46d4ccb330f2a40a682d49dda5f4844962b7dce9fe44aaec Writing manifest to image destination Storing signatures / # uname -a Linux 21bd9e863f71 5.12.7-300.fc34.x86_64 #1 SMP Wed May 26 12:58:58 UTC 2021 x86_64 Linux
In another terminal on your Mac check what’s running
mac $ podman ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 21bd9e863f71 docker.io/library/alpine:latest sh 4 minutes ago Up 4 minutes ago beautiful_ishizaka
And also from your Linux host try the same
fedora $ podman ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 21bd9e863f71 docker.io/library/alpine:latest sh 4 minutes ago Up 4 minutes ago beautiful_ishizakaNote
podman and docker typically default to different registries so for example
docker run -d httpdwill default to
podmanwill not. So make sure to qualify your image names or you may see unexpected results.
podman system info
Add podman remote system
Remove podman remote system
List podman systems
Make podman system
So now you can seamlessly run containers using
podman on one, or more, remote systems.
This HOWTO can easily be extended to allow access to a similar remote service running as
root if necessary. <INSERT usual security warnings!!>
In future articles I want to explore topics including:
Creating podman based
Running your own long lived registry