Make hostname overridable

[stealthybox]

jun 15 ignite meeting notes

@darkowlzz suggested we use the vm name instead of the ID for hostname, so that it would be easier to identify Nodes in a kubernetes cluster.

We thought about the docker UX for hostname:

• container's hostnames are the container ID
• container's can be configured with an overridden hostname (ex: --hostname)

We considered the configurable hostname UX when starting, stopping, restarting, and using ignite vm's for things like AB deploys / traffic-shifting.

Configuring the hostname to be overridden is a good thing for ignite users. The UX is slightly more complicated than just using the VM name in DHCP, but the VM ID is more reliable behavior, and we can match docker's UX here.

The change will likely need:

• bump APIVersion to v1alpha3
• add hostname field to VMSpec
• add --hostname flag to vm create and run commands
• conditionally override hostname config for ignite-spawn's DHCP server
• ensure /etc/hostname is set correctly