podman commit: does not create entrypoint?

[edsantiago]

# podman run --name foo fedora date
Tue Apr  3 15:05:07 UTC 2018
# podman commit --quiet foo myimg
# podman run myimg
No command specified on command line or as CMD or ENTRYPOINT in this image

Expected: date output.

podman-0.3.5-1.gitdb6bf9e.fc27.x86_64

[mheon]

Podman commit needs to be changed to accept an image config (entrypoint, CMD, etc). We can store the ones the container was created with on the podman side (they're probably in create config anyways) and feed them into commit.

[mheon]

This should probably happen as part of the commit overhaul to use Buildah code and actually commit diffs (instead of export-import) that is covered by #520

[TomSweeneyRedHat]

Related to #520

[edsantiago]

When and where should I expect to see this fixed? I'm still seeing the same behavior. Setup:

podman-0.4.4.1524346805-gitcf1d884.fc27.x86_64
buildah-0.16-1524410543.gitd84f05a.fc27.x86_64

Curiously, if you s/fedora/rhel7/ in comment 0, podman silently does nothing and exits 0. (No error message).

[mheon]

The code has landed, so if it's not working, we have a new bug with the way we use buildah to commit.

[edsantiago]

@TomSweeneyRedHat @baude can one of you perform the comment-0 test on what you believe should be a working system setup, and either reopen this issue or let me know what I've done wrong in my setup? TIA.

[rhatdan]

Reopening issue to get confirmation of it working or not.

[mheon]

Confirmed locally. @TomSweeneyRedHat does Buildah not set image config from the base image? Or are we just calling into it wrong.

[TomSweeneyRedHat]

@mheon, looks like it's setting it OK to me unless I messed up the below test.

Test Results:

# ctr=$(buildah from centos:7)
Getting image source signatures
Copying blob sha256:469cfcc7a4b3947a4fa549c68cf4f8570be53779725f0c19f3d33d1520b08db0
 69.78 MiB / 69.78 MiB [====================================================] 9s
Copying config sha256:e934aafc22064b7322c0250f1e32e5ce93b2d19b356f4537f5864bd102e8531f
 2.15 KiB / 2.15 KiB [======================================================] 0s
Writing manifest to image destination
Storing signatures

# buildah config --workingdir /tmp $ctr
# buildah config --entrypoint /bin/bash $ctr

# buildah commit $ctr test1
Getting image source signatures
Skipping fetch of repeat blob sha256:43e653f84b79ba52711b0f726ff5a7fd1162ae9df4be76ca1de8370b8bbf9bb0
Skipping fetch of repeat blob sha256:4f4fb700ef54461cfa02571ae0db9a0dc1e0cdb5577484a6d75e68dc38e8acc1
Copying config sha256:5f4b9284fd6a9a6655783b9a9e5ce434ed937484fcd2d00a6fc925543f7afed4
 1.22 KiB / 1.22 KiB [======================================================] 0s
Writing manifest to image destination
Storing signatures
5f4b9284fd6a9a6655783b9a9e5ce434ed937484fcd2d00a6fc925543f7afed4

# buildah from test1
test1-working-container

# buildah run test1-working-container
[root@mrsdalloway tmp]# exit

# buildah inspect --format '{{.Docker.Config.Entrypoint}}' test1
[/bin/sh -c /bin/bash]

# buildah inspect --format '{{.Docker.Config.Entrypoint}}' test1-working-container
[/bin/sh -c /bin/bash]

[mheon]

@TomSweeneyRedHat Alright, so it's how we're calling into buildah to do a commit, then.

[mheon]

@baude PTAL

[edsantiago]

Has anyone tried the three steps in my first comment? Can you get them to work? What am I doing wrong?

# podman run --name foo fedora date
Wed May 23 12:46:26 UTC 2018
# podman commit --quiet foo myimg
8183e7f0a0185b1f307bfa7e01e8623f48f7d319de0ac3d55e2702136b16d7bc
# podman run myimg
No command specified on command line or as CMD or ENTRYPOINT in this image

buildah-1.00-1526305410.gitce8d467.fc27.x86_64
podman-0.5.4-1527007540.git926d07d.fc27.x86_64

[rhatdan]

Do those commands work with Docker.
I think the issue is that you have not specified a CMD or Entrypoint,

# podman commit --change "CMD=date" --quiet foo myimg

Should do what you want. But if Docker automatically takes the CMD used to create the container then we have a bug.

[edsantiago]

Oops - my bad, for not filing it as a docker-compat issue. Yes, docker uses the container's command as an entrypoint:

# docker run --name foo fedora date
Wed May 23 12:53:47 UTC 2018
# docker commit foo myimg
sha256:fd1fb7b03cd06c769b1eee0f14b659ed9fd5142c067a733e1e70658854ab7fe2
# docker run myimg
Wed May 23 12:54:08 UTC 2018

[rhatdan]

Ok I just looked at this in Docker and the problem is podman does not populating the CMD field on the podman run command. I will open a PR>