Advanced Configurations for Kubernetes

These configurations are optional and should only be applied if required by the client’s environment. They allow you to control how Kubernetes schedules and distributes pods within the cluster.

1. Tolerations

Tolerations allow pods to run on nodes with specific taints, defining the conditions under which they can be scheduled.

Each toleration block uses four variables: KEY, OPERATOR, VALUE, and EFFECT. Up to 10 optional blocks can be defined.

Available variables

• TOLERATIONS_1_KEY: Taint key
• TOLERATIONS_1_OPERATOR: Operator (Equal or Exists)
• TOLERATIONS_1_VALUE: Associated value
• TOLERATIONS_1_EFFECT: Effect (NoSchedule or PreferNoSchedule)

Note: leave these variables empty if tolerations are not required.

2. Node Affinity

Node Affinity controls scheduling preferences based on node labels. Enable it by setting ENABLE_NODE_AFFINITY=true.

Main variables

• NODE_AFFINITY_TYPES: Allowed values: required, preferred
• NODE_AFFINITY_EXPR_TYPE: Expression type (e.g., matchExpressions)
• NODE_AFFINITY_KEY: Node label key
• NODE_AFFINITY_OPERATOR: Operator (e.g., In)
• NODE_AFFINITY_REQUIRED_VALUES: Required values (comma-separated)
• NODE_AFFINITY_PREFERRED_VALUES: Preferred values (comma-separated)

Affinity types

• required: requiredDuringSchedulingIgnoredDuringExecution
• preferred: preferredDuringSchedulingIgnoredDuringExecution

3. Pod Affinity

Defines whether pods should run close to other pods with specific labels. Enable it with ENABLE_POD_AFFINITY=true.

Main variables

• POD_AFFINITY_TYPE: Type of affinity (e.g., required)
• POD_AFFINITY_EXPR_TYPE: Expression type (e.g., matchExpressions)
• POD_AFFINITY_KEY: Label key
• POD_AFFINITY_OPERATOR: Operator (e.g., In)
• POD_AFFINITY_REQUIRED_VALUE: Required value
• POD_AFFINITY_PREFERRED_VALUE: Preferred value
• POD_AFFINITY_TOPOLOGY_KEY: Topology key (e.g., topology.kubernetes.io/zone)

4. Pod Anti-Affinity

Defines whether pods should avoid running on the same node or zone as specific pods. Enable it with ENABLE_POD_ANTI_AFFINITY=true.

Main variables

• POD_ANTI_AFFINITY_TYPE: Type of anti-affinity (e.g., preferred)
• POD_ANTI_AFFINITY_EXPR_TYPE: Expression type (e.g., matchExpressions)
• POD_ANTI_AFFINITY_KEY: Label key
• POD_ANTI_AFFINITY_OPERATOR: Operator (e.g., In)
• POD_ANTI_AFFINITY_REQUIRED_VALUE: Required value
• POD_ANTI_AFFINITY_PREFERRED_VALUE: Preferred value
• POD_ANTI_AFFINITY_TOPOLOGY_KEY: Topology key (e.g., kubernetes.io/hostname)