Does changing the LTM root/admin password affect GTM / Big IP DNS? Is there any impact/outage expected? Do I need to do bigip_add command again for all the LTMs? Thanks!
No, there shouldn't be any outage if you only change the password. Once iQuery communication is established between the LTM and GTM's, any further communication is happening using the device certificates (https://support.f5.com/csp/article/K15664), rather than the passwords.
Of course, I've got no insight in your specific configuration, so always a good idea to doublecheck, but I wouldn't expect any outage.
No, there shouldn't be any outage if you only change the password. Once iQuery communication is established between the LTM and GTM's, any further communication is happening using the device certificates (https://support.f5.com/csp/article/K15664), rather than the passwords.
Of course, I've got no insight in your specific configuration, so always a good idea to doublecheck, but I wouldn't expect any outage.
Thanks Alex. It makes sense. So what about when the cert is expiring and I generate a new one (self signed). In that case, do I just run bigip_add again on the Big IP DNS? They are not expiring anytime soon but just interested to know. Thanks!
Yes, bigip_add should do the trick indeed. You can also see the manual process as well as a full overview of what else is involved with the device/server certs, here: https://support.f5.com/csp/article/K16951115
