?? Ever Wondered Why Pods Aren't Scheduled on Master Nodes? ??

?? Kubernetes Taints & Tolerations:

Ever heard of Taints and Tolerations in Kubernetes? ?? These are essential tools for controlling Pod placement on nodes! Let's dive into the details. ??

?? What are Taints and Tolerations?

• Taints are applied to nodes to indicate they should not accept certain Pods.
• Tolerations are set on Pods to specify they can be scheduled on nodes with matching taints. ????

?? How to Taint a Node? Use the following command:

kubectl taint nodes <node-name> key=value:taint-effect          

? What is Taint Effect? Taint effects determine what happens to Pods that don’t tolerate a taint. Here are the three types:

1. NoSchedule: ?? Pods that do not tolerate the taint won’t be scheduled on the node.
2. PreferNoSchedule: ?? The system will try to avoid placing Pods on the node, but it's not guaranteed.
3. NoExecute: ? New Pods will not be scheduled, and existing Pods will be evicted if they don’t tolerate the taint.

?? Key Points About Taints and Tolerations

1. Control Pod Placement: Taints prevent nodes from accepting certain Pods, but they don't guarantee that a Pod with a toleration will run on a tainted node.
2. Not for Direct Placement: Taints and tolerations don't direct Pods to specific nodes—they control where Pods shouldn't go. ???
3. Node Affinity: If you need Pods to run on specific nodes, use node affinity instead! ??

?? Why Don’t Master Nodes Schedule Pods? By default, master nodes have a taint that prevents regular Pods from being scheduled. This keeps the master node focused on running critical management services! ???

To view the taint on a master node, run:

kubectl describe node <master-node-name> | grep Taint        

Stay tuned for our next post, where we'll explore the difference between Taints & Tolerations and Node Affinity! ???? Thanks for reading! ???