Hey Sam, Thanks for your patience. I can now report based on my investigation of the matter:
1. There aren't any guarantees for time synchronization for App Engine, and this is reflected in the material in the docs. In general, there should only be a few milliseconds of drift at the most, but this is just an estimate and should not be taken as a guarantee, which isn't given. 2. Like all of Google's infrastructure, the instances will be kept in sync with one another. The Google-internal NTP is called the TrueTime API and is described in a blog post and an article: [1] <https://googleblog.blogspot.com/2011/09/time-technology-and-leaping-seconds.html> [2] <http://www.wired.com/2012/11/google-spanner-time/>. Tolerances information is not available for this system, but suffice to say it works well enough for all our purposes. 3. Google syncs time with Mountain View, which is is essentially the US Pacific time zone. As far as documentation is concerned, I don't think there is anything we could add right now since there are no guarantees or tolerances. If you have a specific use case that absolutely must use a highly-accurate standard of time, creating a Compute Engine instance / cluster to handle this task in a centralized manner is probably the best option. Few applications have need of such accuracy, though, and I hope this post reassures you about time-sync for instances. Let me know if you have any questions, I'll be happy to help! Regards, Nick Cloud Platform Community Support On Monday, July 25, 2016 at 5:40:39 AM UTC-4, Sam Hill wrote: > > Since I haven't been able to find a definite answer to this I thought I'd > ask here. > > We currently use a go app deployed using GAE which can potentially cause > us problems if we are not receiving a consistent time value. > > Does anyone know how Google sync the time for their app instances and if > anyone has any experience with time drift ? > > There are several posts from a few years back on stackoverflow etc saying > that either NTP is used or to not trust the time between instances. > > Any help greatly appreciated. > > > Sam > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/google-appengine. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/b1060c5c-94e0-4c8f-9b92-afc1dfe7eff6%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
