When changing standby CM to primary, WAE re-register automatically?

Unanswered Question
Jun 18th, 2009

If I switch the role between the existing primary CM and standby CM, all WAE need to register again with the new primary CM IP address. I can go to each WAE and change "central-manager address x.x.x.x" command one at a time. Is there a function that the process can be automated?

Should I give the standby CM the same IP as the primary? then there's no need to use command "central-manager address x.x.x.x".

Thanks

Gary

I have this problem too.
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dstolt Thu, 06/18/2009 - 17:15

Gary,

The primary and standby central managers have different IP addresses and synchronize the CMS dbase between them every 5 minutes. All devices have the standby CM also in their database if they have also synched with the primary CM, so if the primary goes offline and you promote the standby, all the devices will start coming online in the new primary within 3 polling cycles (5-10 minutes usually). You don't have to change the configs at all in the cli. If you then bring the old primary back online, then make sure it's a standby and synchronized with the primary (sh cms info) before swapping back to making it the primary again if you need to.

Hope that helps,

Dan

gwhuang5398 Fri, 06/19/2009 - 08:32

Thanks Dan. Can you please verify if I understand it correctly?

CM1: currently Primary, IP 10.1.1.1

CM2: currently Standby, IP 10.1.2.1

All WAE: registered with 10.1.1.1 as CM

Now I'm switching their roles:

CM1# central-manager role standby

CM2# central-manager role primary

Without any config changes to WAE's, their will register again with CM 10.1.2.1 within 5-10 minutes. So WAE's still think they are registering with 10.1.1.1? or they know they need to register with 10.1.2.1? what about the statement still existing in those WAE's (central-manager address 10.1.1.1)?

Thanks a lot

Gary

dstolt Fri, 06/19/2009 - 08:54

Gary,

The key is that the Standby has had to be online for long enough that all the registered WAEs to have received it in their CMS updates from the Primary CM. This should happen within several polling cycles after it's online in the Primary CM GUI. There is no other GUI or CLI changes needed with this process.

The process for the WAEs to come online in the new Primary CM (10.1.2.1) is automatic. Its sends out a notification that it's the new primary CM and the WAEs respond by starting to communicate with the new Primay CM instead of attempting the old CM. The CLI for all the WAEs will read "central-manager address 10.1.1.1". Once 10.1.2.1 is promoted to the primary role (10.1.1.1 is either demoted to standby, offline or dead), the WAEs will start to come online in the 10.1.2.1 GUI. The GUI on 10.1.2.1 will only become active when it's promoted to Primary. You do NOT have to change the 10.1.1.1 in the CLI of the WAEs unless you want to, however the address of the current CM always shows up in "show cms info" command where you can see the following...

CMS status

Original CM address registered

Current CM address registered

Last CMS synch time (should be roughly every 5 minutes)

Also, before promoting the Standby, use "sh cms info" command to make sure it's current with the Primary CM so you don't have any data lose from the CMS databases not being synchronized. "cms config-synch" is a useful command to run before promoting it if planned if it isn't in synch. Here is a link to the doco on CM role management.

http://www.cisco.com/en/US/docs/app_ntwk_services/waas/waas/v413/configuration/guide/maint.html#wp1159476

Hope that helps,

Dan

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