Storage

kdb Insights Enterprise uses persistent storage for a number of use-cases. There are two types of storage; local and shared.

local storage is only required by a single pod
shared storage will be accessed by multiple pods.

These two types are configured globally by the application, and can be updated as required. It is also possible to override the storage configuration at a component level.

global:
  persistence:
    local:
      storageClass: ""
      storageSize: "20Gi"
    shared:
      storageClass: "rook-cephfs"
      storageSize: "20Gi"

kxi-controller:
  persistence:
    useLocal: true
    storageClass: "standard"
    storageSize: "30Gi"
    accessMode: "ReadWriteOnce"

The global.persistence.local object defines the default storage for components requiring local access patterns.

Variable	Type	Example
`global.persistence.local.storageClass`	`string`	`""`
`global.persistence.local.storageSize`	`string`	`"20Gi"`

The storageSize parameter specifies the default size of the volume to be created. The storageClass defines what underlying storage type to use. kdb Insights Enterprise defaults this to empty ("") in order to use the cluster default.

Storage classes

The global.persistence.shared object defines shared storage defaults. The storageSize defines the default volume size. The storageClass parameter defines the storage class.

Shared storage classes

The global.persistence.shared.storageClass must be configured with a storage class which supports ReadWriteMany semantics. Storage access modes are described in the Kubernetes docs.

Overriding defaults

The previous example showed how to override the persistence for a particular component. This reconfigures the kxi-controller component to use a custom storage configuration.

kxi-controller:
  persistence:
    useLocal: true
    storageClass: "standard"
    storageSize: "30Gi"
    accessModes: "ReadWriteOnce"

Variable	Description
`kxi-controller.persistence.useLocal`	Override the global settings
`kxi-controller.persistence.storageClass`	Name of storage class to use
`kxi-controller.persistence.storageSize`	Size of volume to provision
`kxi-controller.persistence.accessModes`	Access mode

Package storage

One special case is the storage for kdb Insights Enterprise packages. This is part of the main chart and the configuration for modifying it is at the base level.

The default configuration it uses is below. The available fields match previous sections.

global:
..
packages:
  useLocalValues: true
  storageClass: "sharedfiles"
  storageSize: 20Gi

Assembly Storage

Assemblies require the use of persistent storage for persisting databases and stream logs.

There are two sections within an Assembly where these may be defined.

the mounts object relates to database storage
under spec.elements.[*] the rtLogVolume defines the stream log storage.

As part of the base installation, the default storage configuration may be defined. These are used for any assembly that doesn't explicitly define their storage.

kxi-operator:
  config:
    mount:
      storageClass: "rook-cephfs"
      accessModes:
      - ReadWriteMany
    element:
      # storageClass: "standard"
      accessModes:
      - ReadWriteOnce
    rt:
      volume:
        # storageClass: "standard"
        accessModes:
        - ReadWriteOnce

Variable	Type	Example
`kxi-operator.config.mount.storageClass`	`string`	`"rook-cephfs"`
`kxi-operator.config.mount.accessModes`	`[]string`	`["ReadWriteMany"]`
`kxi-operator.config.element.storageClass`	`string`	`""`
`kxi-operator.config.element.accessModes`	`[]string`	`["ReadWriteOnce"]`
`kxi-operator.config.rt.volume.storageClass`	`string`	`""`
`kxi-operator.config.rt.volume.accessModes`	`[]string`	`["ReadWriteOnce"]`

The storageClass defines what underlying storage type to use. If not set it will default to "", allowing the cluster default to be used. The accessModes defines what access modes to request for the created PVC.

Access Modes

Not all accessModes are permitted for each storageClass.

Mount

mounts within an Assembly are the Persistent Volumes used for database storage.

Where an Assembly is applied without defining storageClass and accessModes:

apiVersion: insights.kx.com/v1
kind: Assembly
metadata:
  name: sdk-sample-assembly
spec:
  ...
  mounts:
    hdb:
      type: local
      baseURI: file:///data/db/hdb
      partition: date
      dependency:
      - idb
  elements:
    ...

The above kxi-operator.config.mount values will default the assembly storage as below

apiVersion: insights.kx.com/v1
kind: Assembly
metadata:
  name: sdk-sample-assembly
spec:
  ...
  mounts:
    hdb:
      type: local
      baseURI: file:///data/db/hdb
      partition: date
      dependency:
      - idb
      volume:
        accessModes:
        - ReadWriteMany
        size: 20Gi
        storageClass: rook-cephfs
  elements:
    ...

Element

The spec.elements object defines components of an assembly (databases, streams, pipelines). These components may subscribe to stream data and require persistent storage for the logs.

The kxi-operator.config.element configuration object defines the default storage for this if it has not been provided as part of an assembly.

apiVersion: insights.kx.com/v1
kind: Assembly
metadata:
  name: sdk-sample-assembly
spec:
  ...
  elements:
    dap:
      instances:
        rdb:
          size: 3
          rtLogVolume:
            size: 20Gi
    sm:
      size: 1
      ...
      rtLogVolume:
        size: 20Gi

The above kxi-operator.config.element configuration will default the stream log storage as below.

apiVersion: insights.kx.com/v1
kind: Assembly
metadata:
  name: sdk-sample-assembly
spec:
  ...
  elements:
    dap:
      instances:
        rdb:
          size: 3
          rtLogVolume:
            accessModes:
            - ReadWriteOnce
            size: 20Gi
          ...
    sm:
      size: 1
      rtLogVolume:
        accessModes:
        - ReadWriteOnce
        size: 20Gi
        ...

RT Volume

The spec.elements.sequencer object defines the RT Sequencer components within an assembly.

The kxi-operator.config.rt.volume configuration object defines the default storage for a sequencer if it has not been provided as part of an assembly.

apiVersion: insights.kx.com/v1
kind: Assembly
metadata:
  name: sdk-sample-assembly
spec:
  ...
  elements:
    ...
    sequencer:
      south:
        volume:
          size: 40Gi
      north:
        external: true

The above kxi-operator.config.rt.volume configuration will default the RT Sequencer volume.

apiVersion: insights.kx.com/v1
kind: Assembly
metadata:
  name: sdk-sample-assembly
spec:
  ...
  elements:
    ...
    sequencer:
      north:
        external: true
        volume:
          accessModes:
          - ReadWriteOnce
          size: 20Gi
          ...
        ...
      south:
        external: false
        volume:
          accessModes:
          - ReadWriteOnce
          size: 40Gi
          ...
        ...

Access modes