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PgpoolOpsRequest

What is PgpoolOpsRequest

PgpoolOpsRequest is a Kubernetes Custom Resource Definitions (CRD). It provides a declarative configuration for Pgpool administrative operations like version updating, horizontal scaling, vertical scaling etc. in a Kubernetes native way.

PgpoolOpsRequest CRD Specifications

Like any official Kubernetes resource, a PgpoolOpsRequest has TypeMeta, ObjectMeta, Spec and Status sections.

Here, some sample PgpoolOpsRequest CRs for different administrative operations is given below:

Sample PgpoolOpsRequest for updating version:

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: pgpool-version-update
  namespace: demo
spec:
  type: UpdateVersion
  databaseRef:
    name: pgpool
  updateVersion:
    targetVersion: 4.5.0

Sample PgpoolOpsRequest Objects for Horizontal Scaling:

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: pgpool-horizontal-scale
  namespace: demo
spec:
  type: HorizontalScaling
  databaseRef:
    name: pgpool
  horizontalScaling:
    node: 3

Sample PgpoolOpsRequest Objects for Vertical Scaling:

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: pgpool-vertical-scale
  namespace: demo
spec:
  type: VerticalScaling
  databaseRef:
    name: pgpool
  verticalScaling:
    node:
      resources:
        requests:
          memory: "1200Mi"
          cpu: "0.7"
        limits:
          memory: "1200Mi"
          cpu: "0.7"

Sample PgpoolOpsRequest Objects for Reconfiguring:

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: pgpool-reconfigure
  namespace: demo
spec:
  type: Reconfigure
  databaseRef:
    name: pgpool
  configuration:
    applyConfig:
      pgpool.conf: |-
        max_pool = 30        

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: pgpool-reconfigure
  namespace: demo
spec:
  type: Reconfigure
  databaseRef:
    name: pgpool
  configuration:
    removeCustomConfig: true

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: pgpool-reconfigure
  namespace: demo
spec:
  type: Reconfigure
  databaseRef:
    name: pgpool
  configuration:
    configSecret:
      name: new-custom-config

Sample PgpoolOpsRequest Objects for Reconfiguring TLS:

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: tls
  namespace: demo
spec:
  type: ReconfigureTLS
  databaseRef:
    name: pgpool
  tls:
    sslMode: verify-ca
    clientAuthMode: cert
    issuerRef:
      name: pgpool-ca-issuer
      kind: Issuer
      apiGroup: "cert-manager.io"
    certificates:
      - alias: client
        subject:
          organizations:
            - kubedb
          organizationalUnits:
            - client

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: tls
  namespace: demo
spec:
  type: ReconfigureTLS
  databaseRef:
    name: pgpool
  tls:
    rotateCertificates: true

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: tls
  namespace: demo
spec:
  type: ReconfigureTLS
  databaseRef:
    name: pgpool
  tls:
    remove: true

Here, we are going to describe the various sections of a PgpoolOpsRequest crd.

A PgpoolOpsRequest object has the following fields in the spec section.

spec.databaseRef

spec.databaseRef is a required field that point to the Pgpool object for which the administrative operations will be performed. This field consists of the following sub-field:

• spec.databaseRef.name : specifies the name of the Pgpool object.

spec.type

spec.type specifies the kind of operation that will be applied to the database. Currently, the following types of operations are allowed in PgpoolOpsRequest.

• Upgrade / UpdateVersion
• HorizontalScaling
• VerticalScaling
• Reconfigure
• ReconfigureTLS
• Restart

You can perform only one type of operation on a single PgpoolOpsRequest CR. For example, if you want to update your database and scale up its replica then you have to create two separate PgpoolOpsRequest. At first, you have to create a PgpoolOpsRequest for updating. Once it is completed, then you can create another PgpoolOpsRequest for scaling.

Note: There is an exception to the above statement. It is possible to specify both spec.configuration & spec.verticalScaling in a OpsRequest of type VerticalScaling.

spec.updateVersion

If you want to update your Pgpool version, you have to specify the spec.updateVersion section that specifies the desired version information. This field consists of the following sub-field:

• spec.updateVersion.targetVersion refers to a PgpoolVersion CR that contains the Pgpool version information where you want to update.

spec.horizontalScaling

If you want to scale-up or scale-down your Pgpool cluster or different components of it, you have to specify spec.horizontalScaling section. This field consists of the following sub-field:

• spec.horizontalScaling.node indicates the desired number of pods for Pgpool cluster after scaling. For example, if your cluster currently has 4 pods, and you want to add additional 2 pods then you have to specify 6 in spec.horizontalScaling.node field. Similarly, if you want to remove one pod from the cluster, you have to specify 3 in spec.horizontalScaling.node field.

spec.verticalScaling

spec.verticalScaling is a required field specifying the information of Pgpool resources like cpu, memory etc. that will be scaled. This field consists of the following sub-fields:

• spec.verticalScaling.node indicates the desired resources for PetSet of Pgpool after scaling.

It has the below structure:

requests:
  memory: "200Mi"
  cpu: "0.1"
limits:
  memory: "300Mi"
  cpu: "0.2"

Here, when you specify the resource request, the scheduler uses this information to decide which node to place the container of the Pod on and when you specify a resource limit for the container, the kubelet enforces those limits so that the running container is not allowed to use more of that resource than the limit you set. You can found more details from here.

spec.configuration

If you want to reconfigure your Running Pgpool cluster or different components of it with new custom configuration, you have to specify spec.configuration section. This field consists of the following sub-field:

• configSecret points to a secret in the same namespace of a Pgpool resource, which contains the new custom configurations. If there are any configSecret set before in the database, this secret will replace it.

• applyConfig contains the new custom config as a string which will be merged with the previous configuration.

• applyConfig is a map where key supports 1 values, namely pgpool.conf.

  applyConfig:
    pgpool.conf: |-
      max_pool = 30        

• removeCustomConfig is a boolean field. Specify this field to true if you want to remove all the custom configuration from the deployed pgpool server.

spec.tls

If you want to reconfigure the TLS configuration of your pgpool cluster i.e. add TLS, remove TLS, update issuer/cluster issuer or Certificates and rotate the certificates, you have to specify spec.tls section. This field consists of the following sub-field:

• spec.tls.issuerRef specifies the issuer name, kind and api group.
• spec.tls.certificates specifies the certificates. You can learn more about this field from here.
• spec.tls.rotateCertificates specifies that we want to rotate the certificate of this database.
• spec.tls.remove specifies that we want to remove tls from this database.
• spec.tls.sslMode specifies what will be the ssl mode of the cluster allowed values are: disable,allow,prefer,require,verify-ca,verify-full
• spec.tls.clientAuthMode specifies what will be the client authentication mode of the cluster allowed values are: md5,scram,cert

spec.timeout

As we internally retry the ops request steps multiple times, This timeout field helps the users to specify the timeout for those steps of the ops request (in second). If a step doesn’t finish within the specified timeout, the ops request will result in failure.

spec.apply

This field controls the execution of obsRequest depending on the database state. It has two supported values: Always & IfReady. Use IfReady, if you want to process the opsRequest only when the database is Ready. And use Always, if you want to process the execution of opsReq irrespective of the Database state.

PgpoolOpsRequest Status

.status describes the current state and progress of a PgpoolOpsRequest operation. It has the following fields:

status.phase

status.phase indicates the overall phase of the operation for this PgpoolOpsRequest. It can have the following three values:

Important: Ops-manager Operator can skip an opsRequest, only if its execution has not been started yet & there is a newer opsRequest applied in the cluster. spec.type has to be same as the skipped one, in this case.

status.observedGeneration

status.observedGeneration shows the most recent generation observed by the PgpoolOpsRequest controller.

status.conditions

status.conditions is an array that specifies the conditions of different steps of PgpoolOpsRequest processing. Each condition entry has the following fields:

• types specifies the type of the condition. PgpoolOpsRequest has the following types of conditions:

• The status field is a string, with possible values True, False, and Unknown.
  • status will be True if the current transition succeeded.
  • status will be False if the current transition failed.
  • status will be Unknown if the current transition was denied.
• The message field is a human-readable message indicating details about the condition.
• The reason field is a unique, one-word, CamelCase reason for the condition’s last transition.
• The lastTransitionTime field provides a timestamp for when the operation last transitioned from one state to another.
• The observedGeneration shows the most recent condition transition generation observed by the controller.