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Version: 2.12

Configure your cluster

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This recording presents the essence of this page. It's recommended to read it in full for the motivation and all details.

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Before you can create your cluster, you need to configure the identity and access management (IAM) for your cloud service provider (CSP) and choose machine types for the nodes.

Creating the configuration file​

You can generate a configuration file for your CSP by using the following CLI command:

constellation config generate azure

This creates the file constellation-conf.yaml in the current directory.

Choosing a VM type​

Constellation supports the following VM types:

By default, Constellation uses Standard_DC4as_v5 CVMs (4 vCPUs, 16 GB RAM) to create your cluster. Optionally, you can switch to a different VM type by modifying instanceType in the configuration file. For CVMs, any VM type with a minimum of 4 vCPUs from the DCasv5 & DCadsv5 or ECasv5 & ECadsv5 families is supported.

You can also run constellation config instance-types to get the list of all supported options.

Fill the desired VM type into the instanceType fields in the constellation-conf.yml file.

Creating additional node groups​

By default, Constellation creates the node groups control_plane_default and worker_default for control-plane nodes and workers, respectively. If you require additional control-plane or worker groups with different instance types, zone placements, or disk sizes, you can add additional node groups to the constellation-conf.yml file. Each node group can be scaled individually.

Consider the following example for AWS:

nodeGroups:
  control_plane_default:
    role: control-plane
    instanceType: c6a.xlarge
    stateDiskSizeGB: 30
    stateDiskType: gp3
    zone: eu-west-1c
    initialCount: 3
  worker_default:
    role: worker
    instanceType: c6a.xlarge
    stateDiskSizeGB: 30
    stateDiskType: gp3
    zone: eu-west-1c
    initialCount: 2
  high_cpu:
    role: worker
    instanceType: c6a.24xlarge
    stateDiskSizeGB: 128
    stateDiskType: gp3
    zone: eu-west-1c
    initialCount: 1

This configuration creates an additional node group high_cpu with a larger instance type and disk.

You can use the field zone to specify what availability zone nodes of the group are placed in. On Azure, this field is empty by default and nodes are automatically spread across availability zones. Consult the documentation of your cloud provider for more information:

Choosing a Kubernetes version​

To learn which Kubernetes versions can be installed with your current CLI, you can run constellation config kubernetes-versions. See also Constellation's Kubernetes support policy.

Creating an IAM configuration​

You can create an IAM configuration for your cluster automatically using the constellation iam create command. If you already have a Constellation configuration file, you can add the --update-config flag to the command. This writes the needed IAM fields into your configuration. Furthermore, the flag updates the zone/region of the configuration if it hasn't been set yet.

You must be authenticated with the Azure CLI in the shell session with a user that has the required permissions for IAM creation.

constellation iam create azure --region=westus --resourceGroup=constellTest --servicePrincipal=spTest

This command creates IAM configuration on the Azure region westus creating a new resource group constellTest and a new service principal spTest.

Note that CVMs are currently only supported in a few regions, check Azure's products available by region. These are:

  • westus
  • eastus
  • northeurope
  • westeurope
  • southeastasia

Paste the output into the corresponding fields of the constellation-conf.yaml file.

Alternatively, you can manually create the IAM configuration on your CSP.

The following describes the configuration fields and how you obtain the required information or create the required resources.

  • subscription: The UUID of your Azure subscription, e.g., 8b8bd01f-efd9-4113-9bd1-c82137c32da7.

    You can view your subscription UUID via az account show and read the id field. For more information refer to Azure's documentation.

  • tenant: The UUID of your Azure tenant, e.g., 3400e5a2-8fe2-492a-886c-38cb66170f25.

    You can view your tenant UUID via az account show and read the tenant field. For more information refer to Azure's documentation.

  • location: The Azure datacenter location you want to deploy your cluster in, e.g., westus. CVMs are currently only supported in a few regions, check Azure's products available by region. These are:

    • westus
    • eastus
    • northeurope
    • westeurope
    • southeastasia

  • resourceGroup: Create a new resource group in Azure for your Constellation cluster. Set this configuration field to the name of the created resource group.

  • userAssignedIdentity: Create a new managed identity in Azure. You should create the identity in a different resource group as all resources within the cluster resource group will be deleted on cluster termination.

    Add three role assignments to the identity: Owner, Virtual Machine Contributor, and Application Insights Component Contributor. The scope of all three should refer to the previously created cluster resource group.

    Set the configuration value to the full ID of the created identity, e.g., /subscriptions/8b8bd01f-efd9-4113-9bd1-c82137c32da7/resourcegroups/constellation-identity/providers/Microsoft.ManagedIdentity/userAssignedIdentities/constellation-identity. You can get it by opening the JSON View from the Overview section of the identity.

    The user-assigned identity is used by instances of the cluster to access other cloud resources. For more information about managed identities refer to Azure's documentation.

Now that you've configured your CSP, you can create your cluster.

Deleting an IAM configuration​

You can keep a created IAM configuration and reuse it for new clusters. Alternatively, you can also delete it if you don't want to use it anymore.

Delete the IAM configuration by executing the following command in the same directory where you executed constellation iam create (the directory that contains constellation-iam-terraform as a subdirectory):

constellation iam destroy
caution

For Azure, deleting the IAM configuration by executing constellation iam destroy will delete the whole resource group created by constellation iam create. This also includes any additional resources in the resource group that weren't created by Constellation.