This topic describes how to use compute profiles for Linux- and Windows-based Kubernetes clusters on vSphere with NSX-T networking and for Linux-based Kubernetes clusters on vSphere without NSX-T networking.

Compute profiles let you customize cluster resources parameters.

How Compute Profiles are Created

TKGI cluster administrators can create and delete compute profiles, as described in the Creating and Managing Compute Profiles with the CLI (vSphere) topic.

After an administrator creates a compute profile, cluster managers (pks.cluster.manage) can create clusters with it or assign it to existing clusters.

List Compute Profiles

To list available compute profiles, run the following command:

tkgi compute-profiles

For example:

 $ tkgi compute-profiles


Name                              Description custom-nodes-compute-profile      custom-nodes-compute-profile custom-node-pools-compute-profile custom-node-pools-compute-profile Dc-east-single-node-pool          A profile for the east datacenter with a single node pool dc-east-mixed                     A profile for the east datacenter with heterogeneous workers

Create a Cluster with a Compute Profile

You can assign a compute profile to a Kubernetes cluster at the time of cluster creation.

To create an TKGI-provisioned Kubernetes cluster with a compute profile, run the following command:

tkgi create-cluster CLUSTER-NAME --external-hostname HOSTNAME --plan PLAN-NAME --compute-profile COMPUTE-PROFILE-NAME --node-pool-instances "NODE-POOL-NAME:INSTANCES"

Where:

  • CLUSTER-NAME is a unique name for your cluster.

    Note: Use only lowercase characters when naming your cluster if you manage your clusters with Tanzu Mission Control (TMC). Clusters with names that include an uppercase character cannot be attached to TMC.

  • HOSTNAME is your external hostname used for accessing the Kubernetes API.
  • PLAN-NAME is the name of the TKGI plan you want to use for your cluster.
  • COMPUTE-PROFILE-NAME is the name of the compute profile you want to use for your cluster.
  • (Optional) --node-pool-instances overrides the worker node instance counts specified in the compute profile:
    • NODE-POOL-NAME is the name of the node pool you want to specify the number of worker node instances for.
    • INSTANCES is the number of worker nodes for the node pool name specified as NODE-POOL-NAME.

For example:

 tkgi create-cluster custom-node-pools -e test.tkgi.shep.api.com –compute-profile custom-node-pools-compute-profile -p “small” –node-pool-instances “tiny-1:3”


TKGI Version:             1.9.0-build.11 Name:                     test K8s Version:              1.18.5 Plan Name:                small UUID:                     
  
   1 Last Action: CREATE Last Action State: in progress Last Action Description: Creating cluster Kubernetes Master Host: test.tkgi.shep.api.com Kubernetes Master Port: 8443 Worker Nodes: 4 Kubernetes Master IP(s): In Progress Network Profile Name: Kubernetes Profile Name: Compute Profile Name: custom-node-pools-compute-profile Tags:

Assign a Compute Profile to an Existing Cluster

TKGI supports changing the compute profile for an already created cluster. You can use this procedure to:

  • assign a compute profile to a cluster that does not have one, or
  • change a cluster’s existing profile to a new one

Note: Compute profiles do not support moving a cluster’s nodes to different Availability Zones.

Warning: Do not scale out or scale in existing control plane nodes by reconfiguring the TKGI tile or by using a compute profile. Reducing a cluster’s number of control plane nodes may remove a control plane node and cause the cluster to become inactive.

This is the procedure to change a cluster’s compute profile:

  1. Do one of the following

    • Choose a new compute profile for the cluster. See List Compute Profiles.
    • Have a TKGI cluster administrator define and create a new compute profile as described in Create a Compute Profile in Creating and Managing Compute Profiles with the CLI (vSphere).
      • The name of the new compute profile must be unique and different from the previously assigned compute profile.

  2. Run the following command to update the cluster with the new compute profile:

    tkgi update-cluster CLUSTER-NAME --compute-profile NEW-COMPUTE-PROFILE-NAME ---node-pool-instances "NODE-POOL-NAME:INSTANCES"

    Where:

    • CLUSTER-NAME is the name of the existing Kubernetes cluster
    • NEW-COMPUTE-PROFILE-NAME is the name of the new compute profile you want to apply to the cluster.

    • (Optional) --node-pool-instances "NODE-POOL-NAME:INSTANCES" updates the number of worker nodes for node pool NODE-POOL-NAME to be INSTANCES. NODE-POOL-NAME should be the name of the node pool in the new compute profile.

      For example:

     tkgi update-cluster test –compute-profile new-compute-profile
    

    Update summary for cluster test: Compute Profile Name: new-compute-profile Are you sure you want to continue? (y/n): y Use ‘tkgi cluster test’ to monitor the state of your cluster

Compute Profile Update and Resize Validation

There are strict validation rules for the tkgi update-cluster --compute-profile command:

  • You cannot use the compute profile to change Availability Zones of a cluster.
  • If any optional field is unspecified at the time of cluster creation or cluster update, then the value of that field is set to the value of the corresponding field from the plan.
  • Values passed to --num-nodes are ignored.
  • Values passed to --node-pool-instances must match the labels of the node pools specified in the compute profile.

Clusters created with compute profile in TKGI 1.8 and earlier:

  • You cannot update a compute profile for a cluster that already has an associated profile created in TKGI v1.8 or earlier.

Resize a Cluster that Has an Existing Compute Profile

TKGI supports using the CLI to resize a cluster already created or assigned with a compute profile, without having to create a new compute profile.

To do this, run the tkgi update-cluster command with the --node-pool-instances option. Pass in a comma-separated list that associates node pools defined in the compute profile with new instance counts. This changes the number of instances from each node pool. The node pools must already be defined in the cluster’s compute profile.

For example, to resize a cluster custom-node-pools-cluster to use three nodes from the node pool named tiny-1 and seven from the pool named medium-2:

 tkgi update-cluster custom-node-pools-cluster –node-pool-instances “tiny-1:3,medium-2:7”

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