What is a “Step Ticker”

You know, it’s one of those little pedometer things you strap onto your hip and tracks how far you’ve walked. Ok, so it’s not that. At least not within the context of servers & virtualization. So what IS it? It’s a horribly named NTP (network time protocol) concept. Yup. That’s it. You were expecting at least two other paragraphs, no?

What does it do?

Hate to disappoint, this paragraph is going to be short too. A Step Ticker is basically a way to tell the NTP daemon to check a server or two, and correct time on startup, rather than relying on the time that was restored from the hardware.

This is meaningful, because often the hardware time has drifted. If you are running applications that are exceedingly time sensitive, like virtualization, you’ll of course want accurate time. So setting up Step Tickers is a “Good Idea”. So how do we do that?

Setting Up Step Tickers

I’ll show you how to do this on a single host, as well, that’s easy, and I’m lazy. To deploy in mass, you’ll likely want this as part of your kickstart process. If you don’t have automated builds, shame on you, but you should have it as part of your QC process then. As for scripting the change out to each host, that is best left to you, the reader (but can be done in PoSH with plink).

Enough rambling, open /etc/ntp/step-tickers and add some lines that look like this

0.vmware.pool.ntp.org
1.vmware.pool.ntp.org
2.vmware.pool.ntp.org

From here, save the file and restart ntp (service ntpd restart).

Questions? Drop a line in the comments.

Sources: Tripwire KB, VMware KB, and some random UseNet/Mailing list  post about ntpd.

Had a situation in which time in a Linux guest kept creeping about, slower, faster, etc. To the point where NTP wasn’t helping before. This in turn, like all good questions, turned me to that which is the holy oracle of all knowledge: Google.

Google, showed me that I am not alone in my struggles, and gave me some direction in my quest. That direction was to VMware’s KB 1006427: Timekeeping best practices for Linux

It seems as each distribution does things slightly differently, there are kernel parameters that can be set to overcome the time slippage.

This article presents best practices for Linux timekeeping. These recommendations include specifics on the particular kernel command line options to use for the Linux operating system of interest. There is also a description of the recommended settings and usage for NTP time sync, configuration of VMware Tools time synchronization, and Virtual Hardware Clock configuration, to achieve best timekeeping results.