There is an additional option I didn't go into--Remediation Script. If you wish, and if you trust your scripting and NCM's work, you can set up an automatic remediation script that can fix (or seriously mess-up) all of your configurations.
NCM can search for your string and if it's not found, it can add it into your configurations automatically.
All you need do is enter in the Remediation script you need. For example, if your desired string isn't found, then NCM could automatically perform the following if you entered it into the Remediation Script section:
conf t
logging 192.168.10.20
end
wr
Just keep in mind that NCM would apply this to EVERY device that the policy references. That's OK if all your devices use the same script syntax, and if they all must point at the same syslog server.
But I've found that there are some subtle (or not-so-subtle) differences between the required Cisco syntax in ASA's, IOS, IOS-XE, NX-OS, Wireless Controllers, etc. The command that works for one may not work at all in all the others. Worse, depending on the command, I wouldn't be surprised to learn one command that's good for some OS's could actually cause problems when applied to others.
I'll leave that for you to work out. I've used the logging command safely, and when it doesn't work on one OS or on the WLC's, it's not a big deal. I just let those fail, and deal with them manually. But be forewarned about applying it across multiple platforms or OS's. Before doing so I recommend you first test/verify the command is valid on all the versions and platforms and OS's.
Yours,
Rick S.