Add testing for kdump over network

[jbtrystram]

We could host {SSH,NFS} server into a container like the tang test as well but the main issue i see is that in this scenario we need to :

• start the NFS server (host 1)
• start a coreOS VM with kdump pointing to that NFS server (host 2), then crash it: echo c > /proc/sysreq-trigger
• Check if logs are created into nfs source (host 1) - this is the tricky part.

So that requires access on two separate instances. We could nest them as we do in the iscsi tests, but that's very expensive as it requires pulling COSA and doing an installation each time. it's justifiable in the iSCSI case but i am not sure for kdump.

I haven't read too much into the tang test so I don't know if that's feasible. Quickly looking at the tang test it seems it's just a case of "create a container with some config"

[jbtrystram]

hmmm maybe a way to validate the test would be to simply crash the VM, wait for reboot, mount the NFS destination again and look for the expected files.

This way the source server would be just a "fire and forget" container like the tang test

[mike-nguyen]

Why can't we access both machines during the test?

[travier]

I vaguely remember that there are options for running multiple systems with kola.

Or we could have the first VM export an NFS mount, then start a VM inside it and point it to the host NFS, crash it and wait on the host for reboot to see if the crash dump is in the NFS mount?

[jbtrystram]

Or we could have the first VM export an NFS mount, then start a VM inside it and point it to the host NFS, crash it and wait on the host for reboot to see if the crash dump is in the NFS mount?

Starting a VM inside the NFS host is the same approach as the iscsi test, as I mentioned it's very expensive in term of bandwidth and make the test quite long..

[mike-nguyen]

I think you should be able to access both VMs in kola. If I recall correctly, the tang test sets up one machine with tang running as a container and another machine to use the first machine to decrypt with the tang fingerprint

[jlebon]

I think you should be able to access both VMs in kola.

Agreed, I think the same setup as Tang should work there with port forwarding. It'd be nice to try to do this with the iSCSI tests too, but I think it'd require some finagling to satisfy IP-related requirements (related: coreos/coreos-assembler#3645).