[jamesblonde]

I have heard that the Borg is still quite widely used at Google, and Omega hasn't taken over as had previously been expected. Omega is a distributed scheduler, and we can only speculate as to why Omega hasn't taken over. My speculation would be that the optimistic concurrency control in Omega leads to storms at very high loads - attempts to allocate containers that need to be rolled back because of contention. With PCC at high loads, you get progress.

[nostrademons]

There's also just plain legacy inertia. Many existing systems are on Borg; many of their dependencies are on Borg; most Google engineers are much more familiar with Borg than Omega, and the teammates they might ask for help & advice are also more familiar with Borg than Omega.

Think of how long the Python 2->3 transition has taken (outside Google, not speaking in Google terms anymore). It's been six years, and we're only now reaching the point where Python 3 may be a better choice for green-field projects than Python 2, and Python 3 may never be a better choice for legacy installs. The Borg -> Omega transition has a similar dependency issue (everything runs in the cloud at Google), the learning curve is worse than Python 2->3, and all of Google's code is legacy. That's independent of any technical differences between them, and also irrelevant to whether an organization just getting onto the cloud would be better off with Docker, Mesos, or Kubernetes.

[jamesblonde]

That's an issue, I guess for many apps. However, Google tend to make company-wide technical decisions, and then the entire engineering crowd go there. How many other companies have one SCM instance? None. If there were unrefutable economic gains to be made by moving to Omega today, my guess they would do it.

The technically interesting question is whether decentralized scheduling in the large scale is a solved problem or not. Can we do it better than centralized today?

[nostrademons]

Google absolutely does not make company-wide technical decisions and then the entire engineering crowd goes there. Rather, they make company-wide technical decisions, and over a period of 3-5 years the entire engineering crowd gradually gets there. As we used to say: "There are two ways to do everything at Google: the deprecated one and the one that doesn't work yet." In some cases I've seen up to 3 deprecated systems in flight, plus one that doesn't work yet. Borg's predecessor was finally removed from production shortly before I left in 2014, despite being deprecated around 2005.