Taints in Kubernetes are a mechanism used to ensure that pods are not scheduled on inappropriate nodes. They are applied to nodes and act as a way to repel certain pods unless those pods have a corresponding toleration. This feature is crucial for managing node-level constraints and ensuring that workloads run in the desired compute environments.
Key Points about Taints:
Purpose: Taints are used to prevent pods from being scheduled on specific nodes unless the pods can tolerate the taints. This helps in managing special hardware requirements, isolating workloads, and maintaining node health.
Syntax: Taints are applied using the kubectl taint command with the following syntax:
Taint Value: A string that provides additional information about the taint.
Taint Effect: Defines the behavior of the taint. The possible effects are:
NoSchedule: Pods that do not tolerate the taint will not be scheduled on the node.
PreferNoSchedule: The system will try to avoid scheduling pods that do not tolerate the taint on the node, but it is not a strict requirement.
NoExecute: Pods that do not tolerate the taint will be evicted from the node if they are already running, and new pods will not be scheduled on the node.
Default Taints: Kubernetes automatically applies certain default taints to nodes based on their conditions, such as:
node.kubernetes.io/not-ready: The node is not ready.
node.kubernetes.io/unreachable: The node is unreachable.
node.kubernetes.io/memory-pressure: The node has memory pressure.
node.kubernetes.io/disk-pressure: The node has disk pressure.
node.kubernetes.io/pid-pressure: The node has process ID pressure.
node.kubernetes.io/network-unavailable: The node’s network is unavailable[2][3][5][9].
Use Cases:
Special Hardware: Ensuring that only pods requiring specific hardware (e.g., GPUs) are scheduled on nodes with that ha...
