So far it has been OK with one exception that I'm dealing with now. We have some check scripts that check the status of our Mailfoundry appliances and whenever I restart Nagios, the checks start returning 'NO OUTPUT' and going critical. They are all able to be run on the commandline as the nagios user without issue (and have been working flawlessly for months). Eventually they seem to clear, but just now they've been critical for 12 minutes. I've restarted Nagios again to no effect. Still looking at what might be causing this, but I can't figure what would have changed between previous versions of XI and this one that would cause this.
They are active checks - a shell script that calls lynx to scrape a web page on the appliance. When I tell Nagios to recheck them after the first failure, they fail again - meanwhile on the commandline as the Nagios user I am able to run them with no issues.