The module lifecycle stage: Preview
The module has requirements for installation

CassandraClass

The Cluster Wide CassandraClass resource allows restricting the creation of invalid configurations and predefining some values. Every Cassandra resource must be associated with an existing CassandraClass resource. Before deploying the service, all configuration will be checked against the corresponding CassandraClass.

Sizing Policies

The structure allows creating a set of sizing policies for associated Cassandra resources. This helps avoid uneven distribution of CPU and Memory resources on cluster nodes. The determining factor for choosing a particular policy is falling within the cores interval. Then compliance with other fields of the specific policy will be checked.

spec:
  sizingPolicies:
    - cores:
        min: 1
        max: 4
      memory:
        min: 100Mi
        max: 1Gi
        step: 1Mi
      coreFraction: [10%, 30%, 50%]
    - cores:
        min: 5
        max: 10
      memory:
        min: 500Mi
        max: 2Gi
      coreFraction: [50%, 70%, 100%]

Validation Rules

CEL (Common Expression Language) syntax is used to create flexible validation mechanisms. We provide a set of predefined variables that can be used in rule:

  • instance.memory.size int
  • instance.cpu.cores int
spec:
  validations:
    - message: "CPU cores must be between 1 and 64"
      rule: "instance.cpu.cores >= 1 && instance.cpu.cores <= 64"

Affinity

Standard Kubernetes mechanism for managing scheduling of deployed pods.

spec:
  nodeAffinity:
    requiredDuringSchedulingIgnoredDuringExecution:
      nodeSelectorTerms:
      - matchExpressions:
        - key: "node.deckhouse.io/group"
          operator: "In"
          values:
          - "cas"

Tolerations

Standard Kubernetes mechanism for managing scheduling of deployed pods.

spec:
  tolerations:
  - key: primary-role
    operator: Equal
    value: cas
    effect: NoSchedule

Node Selector

Standard Kubernetes mechanism for managing scheduling of deployed pods.

  nodeSelector:
    "node.deckhouse.io/group": "cas"

Usage Examples

Basic Usage

apiVersion: managed-services.deckhouse.io/v1alpha1
kind: CassandraClass
metadata:
  name: default
spec:
  sizingPolicies:
    - cores:
        min: 1
        max: 2
      memory:
        min: 2Gi
        max: 8Gi
        step: 1Gi
      coreFractions:
        - "25%"
        - "50%"
        - "75%"
        - "100%"
  validations:
    - message: "CPU cores must be between 1 and 8"
      rule: "instance.cpu.cores >= 1 && instance.cpu.cores <= 16"
    - message: "Memory must be between 2 and 64"
      rule: "instance.memory.size >= 2 && instance.memory.size <= 64"