kata-ctl: Re-enable network check on s390x

[jodh-intel]

The kata-ctl network check needs to be disabled on s390x using #5435 as that platform apparently doesn't support rust-tls (yet).

If and when rust-tls is supported, the reqwest HTTP crate can be used unconditionally by kata-ctl.

/cc @BbolroC.

[BbolroC]

Thanks for looking into the issue. I will keep an eye on the support.

[hbrueckner]

fyi, the TLS library used by rust-tls, ring lacks support for s390x. There is s390x basic support PR pending since last year: briansmith/ring#1297

Not sure if there are other TLS alternatives for doing the tests or if we need to work and wait on above dependency.

[hbrueckner]

Hi @jodh-intel

I briefly looked at https://github.com/seanmonstar/reqwest and it seems that reqwest can use the native TLS crate (openssl) and being rustls-tls an optional feature. For s390x, I wonder whether simplying removing the rustls-tls feature would be the easiest option to re-enable the test case. Wdyt?

[jodh-intel]

@hbrueckner, @BbolroC - I had problems using reqwest with the native libs on x86_64 due to our rust toolchain using musl as the libc, hence switched to rust-tls.

I'm trying to land the admittedly rather ugly but I think working fix (#5439) to unbreak the Kata CI.

However, it would be great if one of you who has access to s380x h/w could raise a follow-up PR that fixed the problem "more properly". Maybe we could have something like this in the manifest:

[target.'cfg(not(target_arch = "s390x"))'.dependencies]
reqwest = { version = "0.11", default-features = false, features = ["json", "blocking", "rustls-tls"] }

[target.'cfg(target_arch = "s390x")'.dependencies]
reqwest = { version = "0.11", default-features = false, features = ["json", "blocking"] }

But I think you'd still need to find a solution to the musl problem. An alternative might be that we build kata-ctl using the standard libc though as I mentioned on jodh-intel#10 (review).