Resource configuration

Volume storage

By default, a NiFi Stacklet creates five different persistent volume claims for flow files, provenance, database, content and state directories. You can find the default sizes of the PVCs in the NifiCluster reference docs , it is recommended that you configure these volume requests according to your needs.

Storage requests can be configured at role or group level, for one or more of the persistent volumes as follows:

nodes:
  roleGroups:
    default:
      config:
        resources:
          storage:
            flowfileRepo:
              capacity: 12Gi
            provenanceRepo:
              capacity: 12Gi
            databaseRepo:
              capacity: 12Gi
            contentRepo:
              capacity: 12Gi
            stateRepo:
              capacity: 12Gi

In the above example, all nodes in the default group request 12Gi of storage the various directories.

Resource requests

Stackable operators handle resource requests in a sligtly different manner than Kubernetes. Resource requests are defined on role or role group level. On a role level this means that by default, all workers will use the same resource requests and limits. This can be further specified on role group level (which takes priority to the role level) to apply different resources.

This is an example on how to specify CPU and memory resources using the Stackable Custom Resources:

---
apiVersion: example.stackable.tech/v1alpha1
kind: ExampleCluster
metadata:
  name: example
spec:
  workers: # role-level
    config:
      resources:
        cpu:
          min: 300m
          max: 600m
        memory:
          limit: 3Gi
    roleGroups: # role-group-level
      resources-from-role: # role-group 1
        replicas: 1
      resources-from-role-group: # role-group 2
        replicas: 1
        config:
          resources:
            cpu:
              min: 400m
              max: 800m
            memory:
              limit: 4Gi

In this case, the role group resources-from-role will inherit the resources specified on the role level, resulting in a maximum of 3Gi memory and 600m CPU resources.

The role group resources-from-role-group has a maximum of 4Gi memory and 800m CPU resources (which overrides the role CPU resources).

For Java products the actual used heap memory is lower than the specified memory limit due to other processes in the Container requiring memory to run as well. Currently, 80% of the specified memory limit is passed to the JVM.

For memory, only a limit can be specified, which will be set as memory request and limit in the container. This is to always guarantee a container the full amount memory during Kubernetes scheduling.

A minimal HA setup consisting of 2 NiFi instances has the following resource requirements:

  • 1500m CPU request

  • 5000m CPU limit

  • 8448Mi memory request and limit

  • 18432Mi persistent storage

You can find the default resource configuration values in the NifiCluster reference docs .