Ubuntu Noble builders and stacks

[edudar-chwy]

Hi,

Until today, there were a few repositories for noble-based builders and stacks. Most of them were non-functional and had PRs opened more than a year ago to make them proper, but no action was taken. Looks like today these repositories were deleted for good. Is there any word on what that means? Will jammy (2022) be the latest now? Are buildpacks changing direction, and builders and stacks would have to be built differently or manually using more basic tools?

Thanks!

[dmikusa]

Hi @edudar-chwy! Good question. This change was in response to a RFC, so it was intentional. Noble support is planned, it will just have a slightly different arrangement, which we are doing to streamline and reduce maintenance overhead for the project.

tl;dr...

1. There will be a single builder going forward, starting with Noble
2. You control the base image for your app by using the --run-image flag with pack build.

You can see the available run-images here.

Ex: pack build apps/maven --builder paketobuildpacks/ubuntu-noble-builder-buildpackless --run-image paketobuildpacks/ubuntu-noble-run-tiny -b paketo-buildpacks/java --path ./target/demo-0.0.1-SNAPSHOT.jar

Note 1: the --builder flag is pointing to a "buildpackless" builder. These builders do not include any buildpacks, so you must include the -b argument to indicate what buildpacks you want. At the moment, we only have a buildpackless Noble builder, but are hoping to have one with a subset of buildpacks soon. The builder is the last step as we update and verify buildpacks to run on the Noble stack.

Note 2: You can omit the --run-image flag and you'll get the base run-image, as that is the default on the builder.

Please let me know if you have any questions.

[dmikusa]

It didn't fly, and the app failed to start with error while loading shared libraries: libstdc++.so 6: cannot open shared object file: No such file or directory error. Switching it back to builder = "paketobuildpacks/builder-jammy-buildpackless-tiny" solves this.

Can you expand on this? If your app requires C++ libraries, I would expect you to get this error on any of the run-images that are tiny. They should all be the same base for that run image.

Can you confirm with your app?

• Builder paketobuildpacks/builder-jammy-buildpackless-tiny - Runs or fails?
• Builder paketobuildpacks/ubuntu-noble-builder-buildpackless with run-image paketobuildpacks/ubuntu-noble-run-tiny - Runs or fails?
• Builder paketobuildpacks/builder-noble-buildpackless-tiny - Runs or fails?

I want to make sure we don't have a regression from Jammy to Noble. Thanks!

[edudar-chwy]

With GraalVM 25 Native Image:

• paketobuildpacks/builder-jammy-buildpackless-tiny - Everything works.
• paketobuildpacks/ubuntu-noble-builder-buildpackless with run-image paketobuildpacks/ubuntu-noble-run-tiny - build works, but an app fails to start in a container
• paketobuildpacks/builder-noble-buildpackless-tiny - Fails, because the builder image does not exist.
• paketobuildpacks/builder-noble-java-tiny - build works, but an app fails to start in a container

For both failed to start noble options:

> readelf -d app | grep NEEDED
 0x0000000000000001 (NEEDED)             Shared library: [libm.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libstdc++.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libz.so.1]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [ld-linux-aarch64.so.1]

The same for jammy:

readelf -d app | grep NEEDED
 0x0000000000000001 (NEEDED)             Shared library: [libm.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
 0x0000000000000001 (NEEDED)             Shared library: [ld-linux-aarch64.so.1]

[dmikusa]

Huh, that's an interesting one. I'm not sure how two images would behave differently. The paketobuildpacks/builder-jammy-buildpackless-tiny uses the paketobuildpacks/run-jammy-tiny run image as its default.

I compared that to the paketobuildpacks/ubuntu-noble-run-tiny which should be the same and I don't see any package differences.

It looks like it is failing because of the stack issue you referenced on noble, which should also fail on jammy.

Is there any way you could provide a sample app that reproduces this? I can try to dig into it more and see what it's doing.

---

Side note, it does look like we can address the issue you referenced and include those libraries. The size increase is small, and they look like they'll address some other open issues as well. Stay tuned on that.

[edudar-chwy]

I can't do the one I'm experimenting with because it's built on top of proprietary extensions and plugins, but I'll try to put together a trimmed-down version that does the same later.

[dmikusa]

Many thanks