security

The endpoint count is larger than the node count and that surprises everyone building their first cluster. What has to be reachable, why this network must survive when every other one is down, and the security posture it needs because it can power-cycle the entire fleet.

Isolation has to be physical where it matters and logical where it can be, and picking the boundary wrong is either expensive or a security problem. What partitions cleanly, what does not, and the allocation unit that decides fragmentation and margin.

How you reported it matters more than how you found it. The internal disclosure that gets a fix instead of a defensive reaction, the four places isolation gaps hide in GPU infrastructure, and the test that keeps the fix from regressing.