Forum Discussion
dcarterjr
Altostratus
AltostratusAdd LTM to existing HA pair
I need to add 2 LTMs to an exsiting HA pair, and create a second traffic group in that device group. The second pair are in a different location. I've looked at many F5 articles, and it looks doabl...
dcarterjr I believe the best route would be to create the new traffic group on the existing pair first to confirm it functions. After that you should be able to add in the other devices to the HA pair the same as any other F5 HA setup. This article might help you with your configuration.
https://clouddocs.f5.com/training/community/adc/html/class1/module1/lab4.html
The only concern I would have is latency between the 4 devices because those other devices are at a different location. As long as you can extend your subnets for the existing pair to the other location for the two new devices it should be possible to configure this setup.
Paulius
MVP
MVPdcarterjr As far as adding in a 3rd device and a new traffic group I don't believe you really have to worry about much. What is the desired end result when you are done with this project? Will you have 4 devices, 2 new in HA, and 2 old in HA at the same location as the new F5s? With this information we might be able to come up with a more appropriate migration advice.
dcarterjrAltostratus
AltostratusThe plan right now for the first scenario is to end up with 2 devices in the new location only once everything is moved, although I'm not sure there's currently a plan for the 2 exisitng boxes.
In the secod scenario, I've suggested ending up with all 3 boxes in the new location once everything is moved, running both traffic groups, one on each of 2 active boxes, with the 3rd as a standby, since we don't have a use for a standalone.
I have also suggested running 2 traffic groups on the HA pair and running active/active, but that's a different discussion.
- Paulius
dcarterjr I would just have the 2 devices in HA running as active/standby because it makes things so much simpler unless it is absolutely necessary that you run them active/active? To add in the 3rd device would be simple but adding the additional traffic group would most likely cause blips in connectivity when you start to shuffle virtual servers around to specific traffic-groups. I have not had the opportunity to shuffle them around after they have been up so I cannot provide any expected behavior other than what makes sense to me on how F5 behaves in most situations. You can keep that 3rd device as a spare to swap out if one of your F5s has a failure and then RMA it while still having HA with 2 devices. I would take this opportunity to make sure the master key on all the F5s is the same.