ashwinikumar-sa/custom-kubernetes-scheduler

This is a custom Kube scheduler which supports placing pods in a specific ratio amoing nodes using node labels

Custom Pod Scheduling in Kubernetes

What is this?

It is a solution to spread pods in a given deployment across nodelabels in a given ratio. This is similar to Amazon ECS capacity provider strategy

Why do I need this?

Customer asking for a way to distribute pods in a specific ratio across nodes

Similar to Amazon ECS Capacity Provider Strategy with base and weights

Usecases includes

• Spread pods between EC2 Spot and On-demand nodes for cost savings
• Spread pods across AZ for High Availability
• Strict compliance requirements for critical applications
• Spread pods on any arbitrary node labels with a given weight

Why cant I use existing Kubernetes Scheduling Constructs?

Existing Kubernetes constructs does not provide this natively

Node Pod Affinity / AntiAffinity provides a best effort but doesn’t guarantee

MaxSkew in 1.19 provides a fixed number for difference in pods count

Custom Pod Scheduling Solutions

• Kube Pod Scheduler
• Custom Pod Scheduling Mutating Webhook