Run a subset of tests on xenial

[kieron-dev]

The latest concourse is using bionic stemcells for its worker VMs, and we have recently moved all our garden deployments to bionic stemcells too. This means we are lacking tests running on xenial stemcells.

We should create a new tagged concourse worker node using the latest xenial stemcell and use it to run both gating and periodic tests. We don't need to check all garden flavours - containerd mode with cpu throttling, say, would be sufficient.

We should also have a garden deployment using the latest xenial stemcell. Note this means we need to automate getting the latest xenial stemcell, as well as the bionic stemcell. We should run GATs against this both in the gating pipeline and periodically.

Update the garden wiki to reflect this change to CI.

[MarcPaquette]

Hi @kieron-dev

Did this work ever get done? If not, I'll work on getting this issue added to the Runtime team's backlog.

Thanks, @MarcPaquette

[kieron-dev]

Hi @MarcPaquette

No - we haven't done this.

[MarcPaquette]

Internal Tracker story for this issue has been generated

[MarcPaquette]

We won't be working on this issue as Xenial will be deprecated within 6 months.