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FerretDBOpsRequest

What is FerretDBOpsRequest

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

FerretDBOpsRequest CRD Specifications

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

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

Sample FerretDBOpsRequest for updating version:

apiVersion: ops.kubedb.com/v1alpha1
kind: FerretDBOpsRequest
metadata:
  name: ferretdb-version-update
  namespace: demo
spec:
  type: UpdateVersion
  databaseRef:
    name: ferretdb
  updateVersion:
    targetVersion: 1.23.0

Sample FerretDBOpsRequest Objects for Horizontal Scaling:

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

Sample FerretDBOpsRequest Objects for Vertical Scaling:

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

Sample FerretDBOpsRequest Objects for Reconfiguring TLS:

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

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

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

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

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

spec.databaseRef

spec.databaseRef is a required field that point to the FerretDB 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 FerretDB 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 FerretDBOpsRequest.

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

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

spec.updateVersion

If you want to update your FerretDB 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 FerretDBVersion CR that contains the FerretDB version information where you want to update.

spec.horizontalScaling

If you want to scale-up or scale-down your FerretDB 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 FerretDB 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 FerretDB 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 FerretDB 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.tls

If you want to reconfigure the TLS configuration of your ferretdb 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.

FerretDBOpsRequest Status

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

status.phase

status.phase indicates the overall phase of the operation for this FerretDBOpsRequest. 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 FerretDBOpsRequest controller.

status.conditions

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

• types specifies the type of the condition. FerretDBOpsRequest 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.