Posts involving my container orchestration system, Orbit
Orbit
Every system needs a front door, and the front door is where you decide what "allowed in" means before anything inside has to care. In Orbit that's the Airlock. Nothing enters a Constellation without passing it: the client proves who they are, the mission proves it&
Orbit
A scheduler is where an orchestrator earns its keep, and it's also where Borg admitted it had painted itself into a corner. The scheduling policy lived in one place, it grew over years to serve every workload Google had, and the paper is candid that the single scheduler
Orbit
The telemetry plane is the easy half of the state split to describe and the easy half to get quietly wrong. It carries everything the cluster observes about itself: usage, health, pressure, liveness, GPU temperature. It's high-volume, it's allowed to be stale, and the entire
Orbit
The Ephemeris is the part of Orbit I was most nervous about, because it's the part that has to be correct. Telemetry can drop a sample and shrug. The ledger cannot drop a placement, can't double-book a node, and can't disagree with itself
Orbit
Before Orbit can place a workload or reclaim a core, it has to know how to say what a workload is. That sounds like the boring part. It isn't. The shape of the object model is where Borg and Kubernetes both left scars, in opposite directions, and getting
Orbit
Last post I said the most important decision in Orbit is splitting cluster state into two planes, and then I made you wait for it. Here it is. If you only read one post in this series, read this one, because almost everything else is downstream of this single cut.
Orbit
Everyone tells you not to build your own cluster manager. They're mostly right. Kubernetes exists, it works, it used all over the place...better job prospects if you use K8s. Building another one is the kind of decision that gets you eyerolls in conversation. So let me undermine