I have 3 slaves nodes in k8s and i'm running kafka (3 cluster). While deploying zk/broker/rest-proxy, its not getting deployed in all the available nodes. How can i make sure that all pods are deployed in different nodes. Do i need to use nodeaffinity or podaffinity ?
If you want all pods to run on different nodes - you must use PodAntiAffinity. If this is hard requirement - you must use requiredDuringSchedulingIgnoredDuringExecution rule. If it's not - use preferredDuringSchedulingIgnoredDuringExecution.
topologyKey should be kubernetes.io/hostname.
In labelSelector put your pod's labels.
I recommend using soft anti-affinity which will look like:
affinity:
podAntiAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- podAffinityTerm:
labelSelector:
matchExpressions:
- key: app
operator: In
values:
- <your app label>
topologyKey: kubernetes.io/hostname
weight: 100Here I explained the difference between anti-affinity types with examples applied to a live cluster: https://blog.verygoodsecurity.com/posts/kubernetes-multi-az-deployments-using-pod-anti-affinity/