bootstrapper: override Cilium MTU auto-detection on GCP (requires Cilium 1.13.0)

[Nirusu]

Proposed change(s)

• override Cilium MTU auto-detection on GCP

This should fix the issues with benchmarking in the CI, where Cilium picks up the MTU from Podman. On normal deployments this should not be an issue so far.

This requires Cilium 1.13.0 as the MTU value does not exist in Helm before, see: https://github.com/cilium/cilium/pull/20639

This workaround could be way easier by hardcoding the network interface to ens3. However, not sure if Google will ever change that in the future, so let's just to it the tedious way I presume.

Draft for now since we need to upgrade to Cilium 1.13.0 first.

Related issue

• Cilium's auto detection picks up the wrong device: https://github.com/cilium/cilium/issues/14339

Checklist

• [ ] Update docs
• [ ] Add labels (e.g., for changelog category)
• [ ] Link to Milestone

[malt3]

Just a heads-up: This branch should be rebased before merge and bazel build files should be generated. This document has up-to-date information on the required tasks (bazel run gazelle).

[Nirusu]

Rebased. Gazelle should be happy without any changes since I didn't touch any imports.

[burgerdev]

It's been some time since this PR was opened and I don't think we have any performance issues due to wrong MTU settings on GCP anymore. There may have been a fix on Cilium's side (although the mentioned issue is still open), or something else changed, but the numbers below look decent to me, even more so compared with the other clouds.

Excerpt from https://github.com/edgelesssys/constellation/actions/runs/9524986833:

gcp-sev-snp

• Commit of current benchmark: 429711bf5db72908a725a52d5fc670527d0560ba
• Commit of previous benchmark: 32588339f345dd02b26dd9e85fa27b382257dad6

Benchmark suite	Metric	Current	Previous	Ratio
read_iops	iops (IOPS)	5325.914	5326.2476	1.0 ⬆️
write_iops	iops (IOPS)	5218.9717	5213.9775	1.001 ⬆️
read_bw	bw_kbytes (KiB/s)	245757.0	246201.0	0.998 ⬇️
write_bw	bw_kbytes (KiB/s)	237253.0	237102.0	1.001 ⬆️
pod2pod	tcp_bw_mbit (Mbit/s)	4999.0	4698.0	1.064 ⬆️
pod2pod	udp_bw_mbit (Mbit/s)	3704.0	3832.0	0.967 ⬇️
pod2svc	tcp_bw_mbit (Mbit/s)	4995.0	4824.0	1.035 ⬆️
pod2svc	udp_bw_mbit (Mbit/s)	3576.0	3832.0	0.933 ⬇️