Delaying VM start up

[Parsious]

Hi Team,

 

I am having an issue that i hope you can give me some advice about.

 

Background.

i am working with a small cluster of VM's that i use as a Dev environment for reasons that im not goint to go into here one of the VM's serves a duel function of Jumpbox and DHCP server for the farm.

 

The issue.

when the server is restarted either as part of an upgrade to Unraid or after a power event the VM's all come back on at the same time this causes an issue where at least 60% of the cluster restarts before the DHCP server is up and ready to pass out credentials.

 

While I'm aware i could get around this completely by assigning statically on each server or allowing a network appliance such as a router to perform the DHCP function this is not an option for me as the operational design of the cluster needs to cover this it self and in the production environment i don't have this issue as the Jumpbox/DHCP is on a separate device to the rest of the cluster and restart of that is controlled in another way.

 

what I'm looking for is a way to delay the startup of all the VM's except the jumpbox/DHCP server for about 30 sec ... this would delay the other servers enough that the DHCP would be ready to service requests.

 

Anyone have any ideas how to do this

 

Cheers

Josh

[testdasi]

Don't use VM autoboot feature and use a bash script instead (use User Scripts plugin to schedule it at array start).

 

That way you can have full flexibility to control the order of vm start (virsh start [VM name]) as well as how much time to wait (sleep [n]s) between boots.

Edited March 19, 2020 by testdasi

[Parsious]

21 hours ago, testdasi said:

Don't use VM autoboot feature and use a bash script instead (use User Scripts plugin to schedule it at array start).

 

That way you can have full flexibility to control the order of vm start (virsh start [VM name]) as well as how much time to wait (wait [n]s) between boots.

and thankyou testdasi thats exactly what I was looking for ... and im kind of pissed at myself for not thinking about a scripted answer. for some reason my brain got stuck in GUI soultion only mode

 

in my defense i did spend all day fighting a VPLS issue at work