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by fyjvd90 2699 days ago
I may not fully understand what the tools can do but it seems overly narrow scoped. Also in that Unix philosophy you don’t duplicate functionality that’s slightly incompatible between tools to the point you need paragraphs and tables to explain when to use which one.
2 comments

Buildah specializes in building OCI images. Podman allows you to pull/run/modify containers created from OCI images. These are distinctly separate tasks, and it seems a lot more straightforward to me than having a daemon (always running, as root...) that handles both tasks.

Podman does allow you to build containers, but my suspicion is it’s intended for easier transitioning from docker (you can alias docker=podman and it just works). Also the build functionality is basically an alias for “buildah bud” so it’s more of a shortcut to another application than re-implementing the same functionality.

Edit: more reading on the intended uses of each tool if you feel like understanding them better https://podman.io/blogs/2018/10/31/podman-buildah-relationsh...

I think that explanation is a little clearer, however the repos and the article don’t make this clear and the fact that podman also builds images makes it less crisp.

> Some of the commands between the two projects overlap significantly but in some cases have slightly different behaviors. The following table illustrates the commands with some overlap between the projects.

And this makes no sense at all if you’re purposely designing a tool.

podman uses buildah to implement "build a container like Docker" functionality... what aspect of that is difficult to understand?

That functionality probably wouldn't be necessary at all if Docker didn't pollute the common understanding of containers in the first place.

See the table of the subtle differences, why does podman create images that aren’t compatible for example? Regardless of what Docker does, if you make tools that are for a specific use case why blur the lines?
The images are compatible. I’m not sure where you’re seeing otherwise.

What is blurry to you about the purpose of either tool?

I don’t think you’re reading the article, it says:

> Each project has a separate internal representation of a container that is not shared. Because of this you cannot see Podman containers from within Buildah or vice versa.

> Mounts a Podman container. Does not work on a Buildah container.

^ this here is one of the problems, the containers are not compatible is my interpretation.

The tool feature sets overlap with subtle differences according to the article, that blurs the line on what each one is for. They need to pick a direction, if you’re making a build tool and a run time, the the build tool must only build, and the run time must only run, or just make one tool. Intentional and truthful (meaning the words mean only what they say) design limits the chaos that happens in the wild, these tools aren’t doing that. It may seem clear to you, but the article is littlerly about how it’s not clear and how they overlap confusingly. So you’re going to come across a mess at some point due to this mistake, that or they could explain their rationale for the overlap but they don’t.

We get this question all the time, and I totally understand the frustration. In a nutshell, here's the breakdown. I will highlight this in blog entries as RHEL8 comes out and emphasizes podman, buildah and skopeo, so you will see more :-)

If you break containers down into three main jobs, with a sort of forth meta-job:

RUN (& FIND) - podman BUILD - Buildah SHARE - Skopeo

If you think about it, that's what made docker special, it was the ability to FIND, RUN, BUILD, and SHARE containers easily. So, that's why we have small tools that map to those fairly easily.