kola: provide internet access to qemu VM

[tormath1]

In this PR, we allow QEMU VMs to access Internet - it was preventing some tests to run because of this dependency.

How to use

Run kola against tests requiring Internet access, example:

$ sudo ./bin/kola run -b cl -p qemu --qemu-image ...  cl.rkt.etcd3
=== RUN   cl.rkt.etcd3
qemu-img: warning: Deprecated use of backing file without explicit backing format (detected format of qcow2)
--- PASS: cl.rkt.etcd3 (27.66s)
PASS, output in _kola_temp/qemu-2021-04-13-1711-9135

What's missing

• update readme with more information the user does not have to perform any manual action. They are done in 3d69f85
• add a teardown method (to remove what kola created)
• run all tests with RequiresInternetAccess flag and remove this flag

[tormath1]

@pothos thanks for the review - comments have been addressed. :)

[tormath1]

@pothos thanks for reviewing again - comments have been addressed. PR is now ready to be fully reviewed :) If it looks good for you, I will rebase my fixups and reword some commits since logic has changed on the road.

[pothos]

I think we should also remove the RequiresInternetAccess flag and PlatformsNoInternet definitions from kola/register/register.go. Or keep the RequiresInternetAccess flag untouched and just remove qemu from PlatformsNoInternet.

[tormath1]

I think we should also remove the RequiresInternetAccess flag and PlatformsNoInternet definitions from kola/register/register.go. Or keep the RequiresInternetAccess flag untouched and just remove qemu from PlatformsNoInternet.

@pothos I removed RequiresInternetAccess flag in (55ea9ee and its parent commit) but not all flag since we are hitting the issue :

=== RUN   cl.locksmith.cluster
--- FAIL: cl.locksmith.cluster (0.10s)
        harness.go:523: Cluster failed starting machines: rendering Container Linux config for platform "": error: platform must be specified to use templating

which should be tracked and addressed in another issue. It's better for now to keep this definitions then.

[pothos]

The failing tests can be excluded with ExcludePlatforms: []string{"qemu"}, until then

[pothos]

cl.locksmith.cluster needs to be excluded

[pothos]

Looks good, thanks!
The only thing I can think of is maybe checking if there is a 172.something network already present like from Docker and not pick addresses in that range (maybe a retry loop). This is not a big problem but it could happen that a container IP address clashes and then the container can't access the network while kola runs…

[tormath1]

@pothos I added the retry logic: we provide the list of the host networks to the generate function then we check if the veth generated host IP is in one of this networks.