Spreading Connectware Workloads Across Kubernetes Nodes

Configure podAntiAffinity to distribute Connectware workloads across Kubernetes nodes for improved availability and resilience

To improve availability and resilience, Connectware can distribute replicas of the same workload across different Kubernetes nodes. This helps ensure that a failure of a single node does not impact all replicas of a component.

Connectware uses Kubernetes podAntiAffinity for this purpose. All scalable Connectware workloads use soft podAntiAffinity by default.

podAntiAffinity Modes

You can control how strictly Kubernetes spreads Pods of the same workload by selecting one of the following modes:

Mode	Behavior of pods with the same workload (e.g., broker).
soft	Default. Kubernetes attempts to place Pods on different nodes, but may schedule multiple Pods on the same node if required.
hard	Kubernetes schedules Pods only on different nodes. If this is not possible, the Pod remains unscheduled.
none	No podAntiAffinity rules are applied. Pods may be scheduled freely.

Topology Key

podAntiAffinity relies on a topology key, which refers to a node label that defines the failure domain used for spreading Pods.

By default, Connectware uses the kubernetes.io/hostname label, which spreads Pods across individual nodes. You can override this behavior by specifying a different topology key, provided that all nodes share the corresponding label.

Configuring Workload Spreading

You configure workload spreading through Helm values for the relevant Connectware service.

1. In your values.yaml file, set the podAntiAffinity Helm value and optionally the podAntiAffinityTopologyKey Helm value for the workload that you want to configure.

The following example configures the broker workload:

broker:
  podAntiAffinity: hard
  podAntiAffinityTopologyKey: kubernetes.io/os=linux

1. Apply the configuration changes via the helm upgrade command:

helm upgrade -n <namespace> <installation-name> -f values.yaml

For details on applying Helm configuration changes, see Applying Helm Configuration Changes.