Actually, I think Google Omega is the next-generation scheduler after their original Borg scheduler, which in-turn inspired Mesos.
The design of Omega is quite different than Mesos. I really do recommend reading the Mesos & Omega papers, they are quite interesting.
And yes, Raft is a consensus algorithm for keeping a set of distributed state machines in a consistent state. Mesos actually uses ZooKeeper under the hood for master election, which uses its own consensus algorithm (ZAB - Zookeeper Atomic Broadcast).
The design of Omega is quite different than Mesos. I really do recommend reading the Mesos & Omega papers, they are quite interesting.
And yes, Raft is a consensus algorithm for keeping a set of distributed state machines in a consistent state. Mesos actually uses ZooKeeper under the hood for master election, which uses its own consensus algorithm (ZAB - Zookeeper Atomic Broadcast).