Improve UI for rolling pool update button

[olivierlambert]

Instead of displaying the button enabled regardless the situation:

• show it disabled if the host is alone in its pool. Display a hover message: "Rooling pool update can only work when there's multiple hosts in a pool with a shared storage"
• show it disabled if some powered up VMs are using a non-shared storage. Hover message: "{number} VMs are currently running and using at least one local storage. A shared storage for all your VMs is needed to start a rolling pool update".

edit: we should probably write an xo-server method to check that. So this can be kept even when we switch to XO 6 UI.

[marcungeschikts]

We'll try to deliver it in the release of September ( XO 5.75)

[olivierlambert]

No rush, if you can it's good :)

[pdonias]

we should probably write an xo-server method to check that. So this can be kept even when we switch to XO 6 UI.

@olivierlambert By putting it in a xo-server method, it means that we have to call it often to refresh the status, whether it's in XO 5 or XO 6. I don't think it would be to hard to put it in xo-web and replicate it in xo-web 6. What do you think?

[olivierlambert]

That's the opportunity to think about a cache system in XO server for the info at some point (eg 10min?). This way we could know in xo web each time we request the check since how long the real check was done. Like "last time it was checked (6min ago), 2 VMs were using a local storage".