Create a database cluster

Creating a cluster on Mission Control is a simple task. Given that your Data Plane clusters have either the appropriate compute capacity or the capability to auto-scale, define a simple MissionControlCluster YAML file and invoke kubectl to create a running DSE cluster.

Mission Control manages or reconciles MissionControlCluster manifests defined either through the User Interface (UI) or through the Command Line Interface (CLI). When a MissionControlCluster resource is created the Mission Control automation picks up the changes and reconciles them into established containers running across the Data Planes.

Prerequisites

  • Because Mission Control organizes clusters by projects, an existing project is required. See create project.

  • A prepared environment on either bare-metal/VM or an existing Kubernetes cluster.

  • For UI Mission Control provides a UI through the IP address of any node using port 30880 on the Control-Plane cluster. For example, issue https://10.0.0.3:30880 from a web browser, where 10.0.0.3 is a qualifying node’s IP address.

Define and create a cluster

Create a cluster by completing the following define and submit tasks. Review the automatic reconciliation workflow, and then monitor the reconciliation status with one kubectl command.

To define a new MissionControlCluster start with creating a new YAML file that defines the topology and configuration for our new cluster. This file is an instance of a MissionControlCluster Kubernetes Custom Resource (CR) and it describes the target end-state for the cluster. What follows is a minimal example of a MissionControlCluster instance which creates a 3-node DSE cluster running version 6.8.26. Each node has 5 GB of storage available for data and requests 32 GB of RAM. See capacity planning documentation for system requirements.

Sample (partial) MissionControlCluster manifest (object):

apiVersion: missioncontrol.datastax.com/v1beta1
kind: MissionControlCluster
metadata:
  name: my-cluster
spec:
  k8ssandra:
    cassandra:
      serverVersion: 6.8.26
      serverType: dse
      storageConfig:
        cassandraDataVolumeClaimSpec:
          storageClassName: standard
          accessModes:
            - ReadWriteOnce
          resources:
            requests:
              storage: 5Gi
      networking:
        hostNetwork: true
      datacenters:
        - metadata:
            name: dc1
          size: 3
          resources:
            requests:
              memory: 32Gi
...

During Mission Control installation, the user interface shares various configuration settings to review or set. Use the reference catalog to guide your configuration decisions.

  1. Specify certain parameters in this CR file.

    1. The apiVersion and kind parameters indicate what type of resource this file represents. In this example, kind is a MissionControlCluster resource with an apiVersion of v1beta1.

    2. This yaml specification outlines metadata associated with this cluster. At a minimum you must specify a name for your cluster. This value is used in the cluster_name parameter of cassandra.yaml.

      Each name must be unique within a Kubernetes namespace. Submitting two clusters with the same name results in the first cluster being overwritten by the second.

    3. Other fields that may be present in the metadata include annotations or labels to provide additional ancillery data. At this time Mission Control does not use any of these fields, but they may be leveraged by automation within the user’s environment.

    4. After the metadata block review the spec, or specification, section. spec is the declaration of our target end-state for the cluster. Instead of describing the various steps to create a cluster you simply define what you want your cluster to look like and Mission Control handles reconciling existing or missing resources towards that end-state.

      See the MissionControlCluster reference for a list of options and their descriptions.

  2. The given MissionControlCluster is saved to disk as my-cluster.`MissionControlCluster.yaml`.

    Any filename is valid here. Using <resource_name>.<kind>.yaml allows you to easily differentiate multiple files in a given directory.

  3. Submit the MissionControlCluster YAML file to the Mission Control Control Plane Kubernetes cluster with kubectl.

    kubectl acts as a Kubernetes API client and handles calls to the Kubernetes API server. Advanced users may choose to leverage programmatic clients or GitOps tooling such as Flux instead of the imperative nature of the kubectl CLI.

    Submission of the object is handled with the kubectl apply sub-command.

    For example:

    kubectl apply -f my-cluster.dsecluster.yaml

    This reads the file specified with the -f flag and submits it to the Control Plane Kubernetes cluster. Should an object exist within the Kubernetes API sharing the same namespace and name it is updated to match the local file. When no file exists a new entry is created. As the new MissionControlCluster object becomes available within the Kubernetes API, Mission Control detects the new resource and immediately begins reconciliation.

Mission Control automatic reconciliation steps for MissionControlCluster resources

The following steps describe the automated process for informational purposes only; no user intervention is required.

  1. Cluster-level operators detect a new MissionControlCluster custom resource through the Kubernetes API within the Control Plane.

  2. Cluster-level operators identify which Data Plane clusters should receive datacenters defined within the MissionControlCluster. In this example the east Data Plane cluster is specified so datacenter-level resources are created and reconciled there.

  3. Datacenter-level operators within the Data Plane clusters detect new datacenter-level custom resource definition (CRD) via the Kubernetes API

  4. Datacenter-level operators generate and submit rack-level resources (StatefulSets) to their local Kubernetes API.

  5. Built-in Kubernetes reconciliation loops detect the new rack-level resources and begin creating pods and storage resources representing the underlying DSE nodes.

  6. Status of resource creation rises to operators at the datacenter and cluster levels.

  7. When all pods are up and running the cluster-level operator signals the datacenter-level operators to begin bootstrap operations of DSE within the created and running pods.

  8. As pods come online their status is escalated and operations continue until all 3 nodes are up and running with services discoverable via the Kubernetes API.

Monitor bootstrap progress

  1. Monitor the progress of the bootstrap to determine completion status or note any errors.

    After submission of the MissionControlCluster custom resource (CR) the operator modifies the resource within the Kubernetes API adding a status field to the top-level of the resource. This status field provides valuable insight into the health of the MissionControlCluster as one or more operators detect definition changes. status indicates everything from reconciliation phase to errors encountered while attempting to create storage. Run the following command to retrieve the descriptive status for the my-cluster MissionControlCluster object:

    kubectl describe mccluster/my-cluster
    Sample results 
    Name:         my-cluster
Namespace:    default
Labels:       <none>
Annotations:  <none>
API Version:  missioncontrol.datastax.com/v1beta1
Kind:         `MissionControlCluster`
Metadata:
  Creation Timestamp:  2023-10-30T11:09:33Z
  Finalizers:
    missioncontrol.datastax.com/finalizer
  Generation:        1
  Resource Version:  105388250
  UID:               57e956f8-1f87-422f-a7f8-b9ec87b956c4
Spec:
  Create Issuer:  true
  Encryption:
    Internode Encryption:
      Certs:
        Cert Template:
          Issuer Ref:
            Name:
          Secret Name:
        Create Certs:   true
      Enabled:          true
  k8ssandra:
    Auth:  true
    Cassandra:
      Datacenters:
        Dse Workloads:
        Metadata:
          Name:  dc1
          Pods:
          Services:
            Additional Seed Service:
            All Pods Service:
            Dc Service:
            Node Port Service:
            Seed Service:
        Per Node Config Init Container Image:  <name>/yq:4
        Per Node Config Map Ref:
        Racks:
          Name:   rack1
        Size:     3
        Stopped:  false
      Metadata:
        Pods:
        Services:
          Additional Seed Service:
          All Pods Service:
          Dc Service:
          Node Port Service:
          Seed Service:
      Per Node Config Init Container Image:  <name>/yq:4
      Resources:
        Requests:
          Memory:      32Gi
      Server Type:     dse
      Server Version:  6.8.26
      Storage Config:
        Cassandra Data Volume Claim Spec:
          Access Modes:
            ReadWriteOnce
          Resources:
            Requests:
              Storage:         5Gi
          Storage Class Name:  standard
      Superuser Secret Ref:
        Name:          my-cluster-superuser
    Secrets Provider:  internal
Status:
  Conditions:
    Last Transition Time:  2023-10-30T14:08:08Z
    Message:
    Reason:                UpdatingIssuers
    Status:                False
    Type:                  UpdatingIssuers
    Last Transition Time:  2023-10-30T14:08:08Z
    Message:
    Reason:                UpdatingCertificates
    Status:                False
    Type:                  UpdatingCertificates
    Last Transition Time:  2023-10-30T14:08:08Z
    Message:
    Reason:                UpdatingReplicatedSecrets
    Status:                False
    Type:                  UpdatingReplicatedSecrets
    Last Transition Time:  2023-10-30T11:16:38Z
    Message:
    Reason:                UpdatingCluster
    Status:                False
    Type:                  UpdatingCluster
    Last Transition Time:  2023-10-30T14:08:08Z
    Message:               Ready
    Reason:                Ready
    Status:                True
    Type:                  Ready
Events:                    <none>

  2. Access operator logs to discover more detail:

    kubectl logs -n mission-control <pod-name>

    An example <pod-name> is mission-control-controller.

    The StatefulSet controller is one of the core Kubernetes controllers that creates the pods. There is one pod per StatefulSet:

    demo-dc1-rack1-sts-0

    demo-dc1-rack2-sts-0

    demo-dc1-rack3-sts-0

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