Maintenance mode for SR

[olivierlambert]

Use case

When we do some maintenance on a shared SR, we need to shutdown all VMs with at least one disk on it and disconnect the PBD. When the maintenance is done, we need to reconnect the PBD and start all related VMs.

That would be nice to get this automated with a single button, like "host maintenance" but for an SR.

Workflow

When the maintenance mode button is clicked in advanced tab of SR:

1. Collect all VMs having one disk in this SR
2. Ask user with modal on all affected VMs will be shutdown
3. Shutdown all affected VMs (warning if it's current XOA!)
4. Disconnect PBDs

Button got now "Disable maintenance". When clicked:

1. Reconnect all PBDs
2. Start all affected VMs

Future versions

It would be great to get this accessible with a simple/REST API. Also, since it's a long async operation, what about having the possibility to set a webhook when it's finished? (that could be used from the NAS perspective)