pool-wide HA configuration

[rocksfrow]

I would like to see XenCenter's HA management pool-wide added to XO.

Rather than it be a small little option in 'Advanced', it deserves it's own tab 'HA', imo.

I'd like to see it implemented almost exactly as XenCenter does it because it works great.

If HA is toggled on, you should see the status with the option to toggle it off.

A few points for when you toggle HA on:

• You can set 'restart priority' to 'Restart', 'Restart if possible', or 'Do not restart'. I guess the current VM 'enabled' is setting it to 'Restart'?
• You can define a start order of the enabled hosts (to ensure one VM starts after another)
• You can set a 'start VM after X seconds' delay interval value.

I'm not sure how you want to handle it, but I know the VMs all have to have xen tools installed, as well as a few other criteria or it won't even let you enable HA.

Finally, you can set a pool-wide 'fault tolerance' value which is just the # of failures that can be handled. There will be a max value depending on the size of your pool and resources, but you can decrease it but cannot exceed it.

You already outlined most of this here: https://xen-orchestra.com/blog/xenserver-and-vm-high-availability/

As far as XenCenter goes, this has remained pretty constant since XenServer 6.2 (and maybe earlier).

[rocksfrow]

NOTE: start order and interval/delay all default to 0

[svenvogel]

@olivierlambert thanks. is there a timeline?

[olivierlambert]

Nope. However, I'd like to emphasis that using HA is dangerous if you don't know exactly what are you doing. Discipline is needed (disable it before any planned maintenance) and can cause more harm than preventing problems. We generally don't push for HA because we saw, on the field, that people with HA had more problems than people without it.