I was launching a couple of Ubuntu 14.04 KVM guests and I ve noticed that time was wrong. OK I thought, a simple ntpdate command and ntp service enabled will fix the issue. Made a reboot of the guest host and show that the time was ok. Then I destroyed the guest and when I checked the time it was wrong. This can’t be right, I thought, and started researching what might be the issue. What I found is that KVM guests should always consider their hardware clock in UTC time while my guests configuration was in local time.
When a browser send a request to an apache web server, apache will send back the response data as well as response headers. You can check what kind of headers are send back with curl command.
$ curl -I http://mysite/
or if the site is on https
$ curl -Ik https://mysite/
Date: Mon, 07 Dec 2015 10:12:52 GMT Server: Apache X-Powered-By: Phusion Passenger (mod_rails/mod_rack) X.X.XX Cache-Control: no-cache