Remove support-and-testing for ubuntu-18.04, add ubuntu-22.04

[dio]

Since 1.24.0, envoy requires a newer glibc:

./envoy: /lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.29' not found (required by ./envoy)
./envoy: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.28' not found (required by ./envoy)

Corresponding CI run: https://github.com/tetratelabs/archive-envoy/actions/runs/3500591896/jobs/5863455940.

We could install a newer glibc on /opt and do patchelf but probably too complicated.

Reference: https://github.com/envoyproxy/envoy/blob/1647d3613d4a23467daaf067c906772e17e8bd3a/ci/README.md#build-image-base-and-compiler-versions envoy build image for Linux uses ubuntu-20.04.

This PR removes running tests on ubuntu-18.04 and adds ubuntu-22.04. Consequently, we skip supporting and testing Envoy on platforms before ubuntu-22.04.

Signed-off-by: Dhi Aurrahman dio@rockybars.com

[codefromthecrypt]

thanks

[codefromthecrypt]

maybe switch this to 22.04 and add a trailing comment to the next line like # envoy x.x is the earliest to support this.

Also mention in the PR desc which versions no longer are testable even if it doesn't matter as we only test ones released?

[cpakulski]

If I am not mistaken, it is not only about testing. It basically means that we do not support ubuntu 18.04 any more. An ubuntu 18.04 user gets "linux" image and it fails to execute because of incompatible default libc libraries.

[codefromthecrypt]

@cpakulski agreed. it is about the compatibility of envoy and the platforms. We can't control that, but we can add notes to our GH action about what is convenient to test. In any case it isn't a real test.

my 2p

Ex. put a header comment like this on the matrix, then qualify the versions like I mentioned here for the current status, knowing that later there will be similar maintenance. The matrix in func-e may need similar notes.

# Operating systems in this matrix can run recent versions of Envoy. This
# needs maintenance as Envoy requires newer versions of libc. The point
# of these tests are only to ensure the tarball wasn't corrupted or built
# for the wrong platform.

[codefromthecrypt]

envoy doesn't have a compatibility matrix though it should. that could be fixed, especially as they attach binaries to releases now. maybe there's a better substitute but this could be linked for now until there's proper docs upstream https://github.com/envoyproxy/envoy/blob/1647d3613d4a23467daaf067c906772e17e8bd3a/ci/README.md

[codefromthecrypt]

coolio