feat: add a new shim for lunatic

[0xE282B0]

Shim for Lunatic "an Erlang-inspired runtime for WebAssembly".

[0xE282B0]

@microsoft-github-policy-service agree company="Liquid Reply"

[Mossaka]

I like that it's already using libcontainer!!

[Mossaka]

Ready for review?

[0xE282B0]

@Mossaka, I wanted to use LibcontainerInstance but can't make it build.

When I enable the libcontainer feature on containerd-shim-wasm it adds libcontainer/default features. With that I need to add th packages libdbus-1-dev and libsystemd0 finally I get the error:

/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/bin/ld: 
    warning: libpthread.so.0, needed by /usr/lib/x86_64-linux-gnu/libdbus-1.so, not found (try using -rpath or -rpath-link)

and

/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/bin/ld: /usr/lib/x86_64-linux-gnu/libdbus-1.so: undefined reference to `sd_listen_fds@LIBSYSTEMD_209'
/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/bin/ld: /usr/lib/x86_64-linux-gnu/libdbus-1.so: undefined reference to `sd_is_socket@LIBSYSTEMD_209'
/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/bin/ld: /usr/lib/x86_64-linux-gnu/libdbus-1.so: undefined reference to `pthread_mutexattr_settype@GLIBC_2.2.5'
/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/bin/ld: /usr/lib/x86_64-linux-gnu/libdbus-1.so: undefined reference to `pthread_mutexattr_init@GLIBC_2.2.5'
/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/bin/ld: /usr/lib/x86_64-linux-gnu/libdbus-1.so: undefined reference to `pthread_mutexattr_destroy@GLIBC_2.2.5'
/usr/local/bin/../lib/gcc/x86_64-linux-musl/9.2.0/../../../../x86_64-linux-musl/bin/ld: /usr/lib/x86_64-linux-gnu/libdbus-1.so: undefined reference to `pthread_condattr_setclock@GLIBC_2.3.3'

Does the libcontainer feater really need to depend on systemd and dbus or am I doing something completely wrong?

[0xE282B0]

When I remove the default features on libcontainer cross compilation works:
containerd/runwasi@00dca5c

@Mossaka, do we need systemd in libcontainer? Is there a way to cross compile with systemd/dbus dependencies?

[Mossaka]

@0xE282B0 can you try "cgroupsv2" feature?

@Mossaka, do we need systemd in libcontainer?

No, musl doesn't have systemd.

[Mossaka]

@0xE282B0 I have a PR containerd/runwasi#246 in runwasi to fix this issue. Once it's merged, you can use cgroupsv2 feature to remove dependencies on systemd and libseccump. This should make it compilable against musl.

[jprendes]

FYI, you can build with the systemd feature in alpine, but:

• you have to vendor dbus, see here and here
• if you want to statically link libseccomp you need a few env-vars, see here

[jprendes]

The systemd feature in youki doesn't link agains libsystemd. It links agains dbus instead.
The dbus crate can be vendored without involving systemd. I do not know if that actually does something in systems without systemd

[Mossaka]

@0xE282B0 I pushed a new commit that updates to the latest main branch of runwasi. It should build now.

[0xE282B0]

@jprendes I think for now it's ok to build the shim without dbus, but statically linking libseccomp is interesting.
@Mossaka Thanks for updating the shim already! I was afraid I would have to wait an hour to see if the workflow was complete 😅

Test just fails with 0/3 nodes available: 3 node(s) had untolerated taint {node.kubernetes.io/disk-pressure: }
I set this now to "Ready for review".

[Mossaka]

LGTM!

I am going to test this locally and then if everything runs fine, will approve this PR.

[Mossaka]

I am running into this problem from the containerd log:

[ERROR] executable "/" does not have the correct permission set
[ERROR] failed to initialize container process: invalid executable: /

I think the issue was the libcontainer requires the entrypoint to be an executable, which we tried to push off. See youki-dev/youki#2220.

In the meantime, you probably want to do something like the spin shim is doing described in the #120.

[Mossaka]

I just pushed a new commit to make lunatic wasm binaries executable.

make integration-tests is working on my local!! 🎉

[Mossaka]

Actually, all the pods are running fine, but the response I got is a bit off. Is this expected?

curl http://localhost:8082/lunatic
<h1>404: Not found</h1>

curl http://localhost:8082/lunatic/hello/     
Hello :)

[0xE282B0]

The path is like spin and wws and the text is just the submillisecond example. What would you expect?

Ah, the integration test URL did not match.

[Mossaka]

The path is like spin and wws and the text is just the submillisecond example. What would you expect?

Thanks for the clarification! I thought we are running the images/lunatic example which confuses me. Now that makes sense.

Ah, the integration test URL did not match.

Yes, I just pushed a commit to fix it.

[Mossaka]

Could you please sign this commit ea3fd9c?

[Mossaka]

@0xE282B0 in PR #125, I am trying to fix the CI with splitting build and integration tests into two jobs and thus reduce the disk pressure issue this PR is facing.

[Mossaka]

Need a rebase to main branch

[Mossaka]

Merging it in!! Thanks @0xE282B0 again for contributing. 🥂