Summit Stack hitless upgrade

[Thomas_Hilber]

Hi guys,
I have a stack with two x480 running XOS 15.3.1.4
Is it possible to upgrade the two switches in the stack one after another so that one of the switches is allways forwarding traffic?
Thanks,
Thomas

[treese]

I'm on version 15.3.1.4 patch1-36 and moving to 16.1.2.14 patch1-1. I want to upgrade a stack one at a time but I'm not clear on this process. Please let me know if I understand correctly. I can install the new image to the non active partitions but reboot to the new install, one stack at a time? Meaning the switches will be running at the same time on two different images ( I just have a 2 stack with both stack ports connected). Or will I need to un-stack them to keep them connected. This situation I'm not using MLAG on the upstream, but I have others that are using sharing to a MLAG connection on my cores. I'll need to work that scenario out too.

Thank you very much.

[treese]

I appreciate all the info. I'll schedule the downtime.

Thank you,
Ted

[Drew_C]

Further, the hitless/rolling upgrade described above would not be supported with the large jump in software version that you're planning.

[Drew_C]

Technically, you can reboot one node at a time, but as each ones comes back up, it won't be able to communicate with the master node and you'd end up with a mess.
"Breaking" the stack would cause you to lose your configuration. Your safest bet is to schedule a reboot of the stack.