Difficulty: Advanced
What is 'requiredDuringSchedulingIgnoredDuringExecution' vs 'preferredDuringSchedulingIgnoredDuringExecution'?
The first is 'Hard' affinity (must match or pod won't schedule). The second is 'Soft' affinity (Kubernetes will try to match, but will schedule elsewhere if it can't).
Scheduling, Soft/Hard