Changing Grid Master

[#1]

hello everyone,

i want to change the grid master role in our infoblox environment, there is much documentation what happens when changing the grid master and what needs to be prepared. Can anyone tell me if and how long there is a services like dns/dhcp will fail?

thanks for your responses,
nils

[#2]

The process is pretty straightforward. On any Grid member that is enabled as a Grid Master Candidate, you connect to its remote console (SSH) and run the command "set promote_master". Follow the prompts and it will take over the Grid Master role, sending out notifications to all online servers in the Grid that it is the new Grid Master.

From there, things can get a little fuzzy. What will happen is that each Grid member will contact the new Grid Master, pull down a new database snapshot and restart. The timing for this sequence of events will vary, especially depending on if you specify a delay when you run the promote_master command. However, the timing for interruptions on each Grid member should be no longer than if you were to restart the Grid member (not a reboot) as the tming for how long this takes depends on how large the database snapshot for it is. In a small setup, this interruption is barely noticable by the clients on the network.

Regards,

Tony

[#3]

hello tony,

thanks for your response!

all members in this grid are clusters, will both nodes in a cluster "restart" at the same time or one after the other?

regards
Nils

[#4 · Accepted solution]

I'm not sure what you mean by clusters. For HA pairs, the change is pushed to the active node and the passive node synchronizes the data from it but no downtime should be noticed for those.

Be sure to look at the section titled "set promote_master" in the NIOS documentation as this talks through a few different use cases and might help answer your question here.

[#5]

sorry, of course i mean a HA pair.

so you mean that the active node will "restart"after this the "passive" node.

thank you tony for your fast response!

regards
nils

[#6]

I suggest checking with support as I was told that during the grid master transfer to a candidate, all services are impacted as all devices will reboot at the same time!!!

[#7]

Well, it is a restart instead of a reboot - so it is faster.

"Order of Restart during a Grid Master Candidate Promotion" is explained in the knowledgebase article # 4307
The article also has a reference to "Scheduling NIOS grid members to restart sequentially"  article # 3162


Best Regards,
Bibin Thomas