9800 ISSU without staggered AP upgrade

[Johannes Luther]

Hi wireless team,

quick question: Is it possible to perform a C9800 ISSU upgrade without doing a staggered AP upgrade.

In big WLC deployments, we have a scheduled downtime within a fixed time window. With staggered AP upgrades, the upgrade takes ages (but is less disruptive). However we want to have the flexibility to perform a predownload of SW but reboot the APs all at once or in bigger blocks.

Is this possible using ISSU or do we have to use a non-ISSU upgrade approach for this?

[balaji.bandi]

i did a recent upgrade to ISSU using DNAC 17. X  to 17.6.4  - with Rolling upgrade or Manually reload

I did not see any issue - but I would advise reading the release notes fixing any prerequisites and understanding the caveats.

if any of that is missed then you need to reboot both controllers to fix the issue.

[Johannes Luther]

Hi @balaji.bandi 

Thank you for your answer. There are no issues at all from a technical side.

The question is, how does the manual reload method work? As soon as I trigger ISSU the following happens:

- Upload new version to WLC and install it
- Predownload SW to APs

- Activate: From now on everything happens automatically ...
- Upgrade of standby WLC to target version
- After standby is reintegrated into cluster with target version: Upgrade of active WLC to target version
  ==> SSO failover to standby

- After active unit has rebooted and is fully reintegrated into cluster with target version -> AP upgrade (staggered)

Question is for the last step: Can I force that all APs are upgraded at once and not in a staggered way?

[eglinsky2012]

I'm interested in this, since I have yet to do a software upgrade on our new 9800s, but I did notice this setting in the software upgrade section of the GUI. Seems you'd want the one-shot option.

[balaji.bandi]

yes one shot option will do all once, but i would not take that risk to be honestly, that will have huge traffic flowing towards Controller side - rather i would do as the option 25%, i am sure this not going to effect majorly, as you mentioned large scale, think all flooding towards controller.

[Rich R]

Yes - it's part of the ISSU options:

Select One-Shot

[Johannes Luther]

I need to check what's the corresponding CLI line ... any ideas?

[Rich R]

WLC(config)#ap upgrade staggered ?
15 15 percent APs per iteration
25 25 percent APs per iteration
5 5 percent APs per iteration
client-steering Enable or disable client steering during staggered AP upgrade
iteration Configure AP upgrade iteration accounting parameters
one-shot All APs in one shot, no staggering

[Rich R · Accepted solution]

The defaults:
WLC#sh run all | inc ap upgrade staggered
ap upgrade staggered 15
ap upgrade staggered client-steering
ap upgrade staggered iteration completion 90
ap upgrade staggered iteration timeout 9

[Scott Fella]

Like what the others mentioned, the one shot is upgrading the whole environment like how it is in AireOS.  The staggered approach what directed for customers whom required that wireless be up and functional during the upgrade.  This is only possible for customers whom has a bigger window for changes or when the staggered approach does not impact wireless.  The staggered approach can still affect some clients that don't move to other adjacent access points, so its not 100%, but at least you have available access point still functioning in your network.  High density vs sparse density can have an affect on the availability of wireless during the staggered approach.  The one shot just makes your small change window reasonable.  Overall, you would still need to account for ap's that fail or even controllers that might fail.