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Podman is a daemon-less alternative to Docker, but with Rootless containers, grouping containers in pods, and systemd integration. What do you think of it? (lemmy.ml)

submitted 1 year ago by cyclohexane@lemmy.ml to c/programming@programming.dev

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Podman is a lot like Docker: a tool for running OCI containers. While it maintains backwards compatibility with Dockerfile and docker-compose syntax, it offers a lot of other benefits:

daemonless: it can run containers without a daemon process running in the background.
Rootless: can run containers without root privileges
pods: can group containers into secluded pods, which share resources and network namespace

Podman has other features I haven't explored yet, like compatibility with Kubernetes yaml file, and being able to run containers as systemd units.

Have you used podman before? What are your thoughts on it?

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[-] sbstp@programming.dev 32 points 1 year ago

I tried replacing some components of my NAS server that were on docker/docker-compose with podman but unfortunately it was not a 100% drop-in replacement. I had networking issues in podman that I did not have in docker.

The network stack is implemented quite differently in podman than in docker, once you start using more advanced features the backward compatibility disappears.

Since it came second, I think it has a lot of technical advantages, avoiding docker's mistakes and what not. In the long term I'll probably switch to it, unless Redhat keeps shooting itself in the foot...

[-] cyclohexane@lemmy.ml 9 points 1 year ago

I personally liked podman's networking a lot more, but my issue is that it is not well documented. I hope that improves.

May I ask which networking issues you had?

[-] sbstp@programming.dev 4 points 1 year ago* (last edited 1 year ago)

I think one of the issues I had was trying to run pihole with podman on a raspberry pi. I could not get DNS requests to work by just mapping the right ports. I ended up just running with --net=host and it worked, I didn't feel like debugging further.

I had other issues on my NAS but I don't remember what it was, I have a lot of services on it, qBittorrent, Wireguard, Jellyfin, Jackett, netdata, prometheus, samba, syncthing, pihole (redundant), wsdd all in docker.

[-] herrvogel@lemmy.world 7 points 1 year ago

I ran into that same DNS issue with pi-hole but in a docker container, and the (bandaid) solution was to put the container in host network mode too. But turns out it's not an issue but a feature. By default pi-hole only responds to DNS queries from within its local network. The host machine's LAN is an external network to the containers, unless you set the container's network mode to host. Pi-hole does have a setting to make it respond to DNS queries from other networks as well, though. What I'm saying is, that might not have been a podman issue.

[-] marx2k@beehaw.org 4 points 1 year ago

You know they're going to

[-] Bizarroland@kbin.social 24 points 1 year ago

I was scrolling through and this caught my eye but I totally misread it on first glance, I thought you typed "Pokemon is a demon" and I had to stop and scroll back cuz I was like oh shit this is going to be a good thread.

[-] chaorace@lemmy.sdf.org 4 points 1 year ago

You're about 20 years late for that particular shitshow, but here's a fun video retrospective on the war on Pokemon if that's your thing.

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[-] eeleech@lemm.ee 15 points 1 year ago

I exclusively use podman instead of docker at work and at home and haven't encountered any unsolvable problems.

[-] darq@kbin.social 15 points 1 year ago

I tried a couple of times to get Docker running rootlessly on my local machine, without just granting root-like permissions to the user. Spent a few hours reading just the worst documentation that tells you to do things with absolutely no explanation of why, feeling like an idiot.

Then I installed Podman. It worked more-or-less out of the box, and I got on with the rest of my project.

[-] ono@lemmy.ca 11 points 1 year ago

Docker has rootless containers, too, although I think Podman has slightly better options for unprivileged uid management.

Daemonless is appealing, especially for low-powered servers. Getting rid of Docker's background resource usage is the main reason Podman is on my to-do list.

I imagine pods could be handy to reduce network configuration for related services.

I like that the tools exist to make Podman a drop-in replacement for Docker, including the building of containers.

I have no interest in systemd; I hope it's optional.

[-] shasta@lemm.ee 1 points 1 year ago

In kubernetes, I often use multiple containers in a pod only to have init containers check certain status of other servers before running the main container. For example, making sure a database is online and I can query data from it. You can just add this to your main container's start script though. Docker has a way to do this sort of thing too but it feels clunky.

[-] cyclohexane@lemmy.ml 1 points 1 year ago* (last edited 1 year ago)

Docker has rootless containers, too, although I think Podman has slightly better options for unprivileged uid management.

I have not used Docker rootless, but I imagine podman has much better and more flexible network configuration as well?

On systemd, I actually do not use systemd either, hence why I said I never tried those features. It is not a hard requirement at all. Though I have not tried to use any integrations with OpenRC and podman

[-] sashanoraa@lemmy.blahaj.zone 9 points 1 year ago

I generally prefer podman to docker at this point for the reasons you stated. However, podman is not 100% compatible with docker, and I have run in to issues with a few tools, that were admittedly poorly written. Mostly around how they deal with file permission when move files in and out of containers.

[-] cypher_greyhat@lemmy.world 5 points 1 year ago

Works great. You can even make it pretend to be Docker so you can use the Docker commands.

[-] DacoTaco@lemmy.world 4 points 1 year ago

Ive been using podman on my nas, and i like it.
It has its issues, but knowing your containers dont run as root just makes me feel more at ease. I dont really understand why a docker should run as root, if the software in the container often run as their own user...

[-] 0x442e472e@feddit.de 2 points 1 year ago

We are trying to use podman as a way to run Testcontainers and build images on a kubernetes cluster using Gitlab CI. Building works, but running Testcontainers doesn't so far :(

[-] jlh@lemmy.jlh.name 2 points 1 year ago

Have you looked into kaniko?