I’d wager it’s mainly just that deployment is mildly more annoying and requires more disparate steps.
Especially if you want to go rootless (and you should).
For someone that isn’t “Linux first” (like a baby developer learning to containerize their apps), the idea of dealing with systemd unit files or kublet configs, and having to created dedicated local service accounts (and remembering to enable linger) is somewhat intimidating when compared to just installing docker, whipping up a docker compose file and pressing “start”.
I understand why they’ve taken this approach but it’s pretty clunky and a bit unfriendly.
It's not just mildly annoying, it completely ruins a great thing.
Docker Compose is to stacks what Dockerfiles are to a single application. Podmans solution is to not commit to compose, but instead to create a bespoke mechanism involving a bunch of tiny files, all of which is insanely system (linux) specific, and therefore completely non-portable.
I genuinely don't understand how someone can see the value of Docker, but then do things so completely "not-docker" when it comes to deployment/stacks/orchestration.
> but instead to create a bespoke mechanism involving a bunch of tiny files, all of which is insanely system (linux) specific, and therefore completely non-portable.
To nit pick slightly, it's not really a bespoke mechanism it's just re-using the mechanisms provided by systemd. Quadlets are implemented as a systemd generator in order to re-use the existing service management system that exists on essentially all major Linux distros. Quadlets are less a direct competitor with compose (hence why Podman implements the compose spec) and more a way to better integrate containers with the rest of a system. The closer Podman native equivalent to compose is Kube files.
> Docker Compose is to stacks what Dockerfiles are to a single application. Podmans solution is to not commit to compose
This isn't (completely) true. I found podman-compose to be a more or less drop-in replacement for docker-compose. I know that in the past support was patchy, but things are rather good now.
Pretty sure that's because podman-compose literally calls docker-compose under the hood.
e: from the manpage:
"podman compose is a thin wrapper around an external compose provider such as docker-compose or podman-compose. This means that podman compose is executing another tool that implements the compose functionality but sets up the environment in a way to let the compose provider communicate transparently with the local Podman socket. The specified options as well as the command and argument are passed directly to the compose provider."
it calls podman-compose or docker-compose depending on what is installed...
this is literally what manpage you quoted says too
That's the "podman compose" wrapper command. podman-compose (the implementation referenced in the first sentence of your quote) does not call docker-compose: https://github.com/containers/podman-compose
The purpose of quadlets is when you want good integration with systemd.
The better equivalent of docker compose is podman kube, which does use a single file. And it isn't bespoke, it uses the same format as kunernetes.
And if you prefer the docker compose format, podman-compose is available as a separate tool.
And FWIW docker compose is a separate tool from docker itself as well (and needs to be installed separately on several linux distros). And can actually work with podman instead of docker.
FWIW, for me docker compose works just fine with podman. I am not sure what kind of additional configuration is needed these days, make sure you are running podman with the socket thing and perhaps set DOCKER_HOST. It's just a client / frontend to an API that podman provides.
IIRC `podman compose` can invoke either `podman-compose` or `docker-compose` and sets up the environment for the call, so I don't think you need to even really do anything special other than install either of the 2 commands
Depends on your point of view.
It can be argued that it’s Docker that is reinventing the wheel and doing its own bespoke process management, journal management etc when all of these are solved problems on Linux. Podman is instead reusing the platform which exists, Quadlets are just reusing systemd, so as a sysadmin I can manage, control and monitor docker containers using the same standard tooling that I already use to manage, control and monitor all the other processes which are running on the system.
Architecturally I find the above argument attractive. The problem is chronology. Docker and docker compose came before systems was ubiquitous and long before Quadlets, so it’s natural to think of Quadlets as reinventing the wheel.
Personally I wish docker had not rejected composition/integration around systemd. Would have made everyone’s job a lot easier in the long term.
> Personally I wish docker had not rejected composition/integration around systemd. Would have made everyone’s job a lot easier in the long term.
It also would have only run on Linux hosts (and not all of those at that), so something else would have been adopted instead. Docker didn't win by being superior to every alternative, it won by being good enough and being everywhere. For portable orchestration, Desktop does ship with kubernetes that's literally one click to enable.
Have you try podman-compose ?
> the idea of dealing with systemd unit files or kublet configs, and having to created dedicated local service accounts
Podman does not require systemd (thank God). I use a simple podman compose up/down in a user systemd file to automatically bring my containers up at boot, but other mechanisms are possible, like quadlets and init scripts.
Quadlets are awesome and honestly I think one of the best additive things that podman has on top of the regular docker toolset.
I use podman regularly, and despite it being a good drop-in replacement like 95% of the time, the 5% of the time where it isn't seamless are super painful. For example, skaffold (https://skaffold.dev/) pukes all over itself when you try to run podman as a drop in replacement. I'm sure there are plenty of other examples, but that one stops me from using podman at work in addition to in my personal projects.
Well, but that's kinda the point, isn't it? You know that other mechanisms are possible, but you opted out for a user systemd file. I know that too, and I also just use systemd for that. Because the alternative doesn't look much easier. I guess it makes sense that they try to discourage it now, because for serious deployment it isn't the best option. But when I install Podman on my laptop, I really wish the systemd configs would be added automatically without me even knowing.
I mean, really, if we keep in mind that formally these are 2 totally unrelated projects, it's hard to complain. Yes, it's almost seamless. But since when installing Podman everyone thinks roughly "I am installing a newer better Docker version", and we all already have a few dozens of custom Docker containers running, it's hard no to wish it was even more seamless and backwards-compatible. I remember the transition process wasn't nearly as smooth as I hoped, and every small glitch is kinda stressful, because you know that currently all of it "somehow works", and if something breaks you probably won't even notice right away.
Are we talking windows here? On Linux and Mac I believe you can install Podman via a package manager like anything else.
Linux. It’s not the installation of podman that can be fiddly. It’s the setting up systemd unit files and local user accounts for rootless / daemonless deployment of containerized apps that can be a headache.
It’s not hard. It’s just fiddly.
> It’s just fiddly.
You could quite simply have a systemd file that calls podman compose up when the service starts and podman compose down when it stops. Basically the same systemd file for every container stack defined in a single compose.yml. It's extremely easy, and does not do stuff behind your back like Docker (such as silently altering iptables rules).
Sure. But that wasn’t OP’s question.
The question was why Podman doesn’t have the adoption levels that Docker does, and my supposition was that (for those that don’t have much Linux administration experience) added steps like systems configs, or quadlets etc are just another barrier to entry that you don’t have with Docker.
I’m not arguing that Docker is better (I think Podman wins in a lot of ways actually) just that Podman requires a bit of extra work to implement well and that is just enough of an annoyance to tip the scales towards Docker.
I think it's just because Docker came before. Podman is more secure and architecturally cleaner, but not touching something that works is an equally good reason not to migrate.
You can just run podman containers as root if you don’t want the fiddllyness of user accounts - it’s no less secure than rootful Docker.
It might not be the popular way here in HN but nowadays I just ask llm to create required configuration files and everything is so easy. Of course you need to review them but tbh no more headaches at least with config files.
Doesn't quadlet fix some or all of those problems? It's supposed to allow you to convert podman containers to systemd unit files automatically
> Doesn't quadlet fix some or all of those problems?
It definitely can solve some of those problems, and that’s the approach I’d generally recommend.
But to answer OP’s question - my supposition was that the mere fact that such a device is even necessary (when compared to docker) is an added work that isn’t obviously easy to implement for someone who is just trying to learn how to containerize their app (and might be a developer but not that experienced with Linux administration) and this one of the main reasons Podman isn’t as popular as Docker.
I think Podman is better in a number of ways, but it isn’t the most intuitive to implement compared to Docker.
I think it’s probably correct strategy wise to just “do the right thing”
They’re essentially long junior devs asking Claude to set up podman
I use podman on my local dev machine and I don't touch any system-d files for that
Its not only intimidating, its clunky and error-prone. That's the answer to OP's question, this podman thing does not have good UX story.
Or, to look at it another way, the answer is that it’s the developers who don’t want to learn something new that, objectively speaking, might turn out to be better than what they’re used to.