I'm trying to determine the best method for upgrading the pair of QFX5120-48Y switches we have that are configured as a Virtual-Chassis, with the least downtime possible. I came across 2 methods of doing this, NSSU and a two-member virtual-chass manual way with minimal downtime:
NSSU:
1) Upgrading Software on a Virtual Chassis and Mixed Virtual Chassis Using Nonstop Software Upgrade
1a) https://supportportal.juniper.net/s/article/EXQFX-NSSU-upgrade-process?language=en_US
Two-member Virtual-Chassis:
2) Upgrading Two-Member QFX Series Virtual Chassis
Reading about NSSU, I saw that success using this method seems to be somewhat hit or miss, and I'd rather use the more stable method, whichever that may be. However, reading about the manual way (the two-member method, which is also geared for the QFX5100, not necessarily 5120), in the "Before you begin" section, that you should make sure the VC is performing only Layer 2 functions, and that it should not be configured in Virtual-Chassis Fabric mode.
We are both using fabric mode (mixed) and have vlans configured, though I'm not sure the vlans are using virtual-chassis. Our configuration:
QFX5120> show virtual-chassis
Preprovisioned Virtual Chassis Fabric
Fabric ID: 5f8f.xxxx.xxxx
Fabric Mode: Mixed
Mstr Mixed Route Neighbor List
Member ID Status Serial No Model prio Role Mode Mode ID Interface
0 (FPC 0) Prsnt SERIALNO1 qfx5120-48y-8c 129 Backup Y F 1 vcp-255/0/54
1 vcp-255/0/55
1 (FPC 1) Prsnt SERIALNO2 qfx5120-48y-8c 129 Master* Y F 0 vcp-255/0/54
0 vcp-255/0/55
and
QFX5120> show configuration | display set | match virtual-chassis
set virtual-chassis preprovisioned
set virtual-chassis no-split-detection
set virtual-chassis member 0 role routing-engine
set virtual-chassis member 0 serial-number SERIALNO1
set virtual-chassis member 1 role routing-engine
set virtual-chassis member 1 serial-number SERIALNO2
We have IRBs configured, and AE interfaces configured as trunks 802.3ad that are LACP active, where one link of a host is on one switch and the other link is on the other switch.
What is the recommended path to go here, and will the IRBs impact either method of upgrade? The manual one seems to break the VC first, then you'd have to rebuild it. So is that actually the best, and how do the vlans/IRBs fit into and/or affect that method? Thanks in advance.
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ANDREW JINKS
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