Cluster configuration options on cloudscale.ch

The OpenShift cluster setup can be customized by configuring .parameters.openshift4_terraform.terraform_variables. This page gives an overview of the configuration options, when setting up a cluster on cloudscale.ch. Further information on the Terraform module and its configuration can be found on GitHub.

Nodes

You have the ability to control the instance size, count, and partition size for each VM type as well as the option to configure additional worker groups through Terraform variables.

See the cloudscale.ch pricing doucumentation for available VM flavors.

Master nodes

Key Default Description

master_count

3

The number of Kubernetes master nodes running the control plane.
We don’t provide support for configurations with master_count != 3.

Infrastructure nodes

Key Default Description

infra_count

3

The number of infrastructure nodes running the OpenShift Container Platform environment

infra_flavor

plus-32-4

Type of the infrastructure node VMs

We currently don’t provide support for any of the following configurations:

  • infra_flavor = flex-*

  • infra_flavor smaller than plus-32-4.

  • infra_count < 3.

Worker nodes

Key Default Description

worker_count

3

The number of worker nodes running the customers workload

worker_flavor

plus-16-4

Type of the worker node VMs

worker_volume_size_gb

128

Worker boot volume size in GBs

We currently don’t provide support for any of the following configurations:

  • worker_flavor = flex-*

  • worker_flavor smaller than plus-16-4.

  • worker_count < 3.

Additional Worker Groups

You have the option to add additional worker node groups. Each worker group is a collection of VMs with the same flavor and volume size.

Worker groups can be configured through the additional_worker_groups variable. This variable is a map from worker group names (used as node prefixes) to objects providing node instance size, node count, node data disk size, and node state.

The following example will add a worker group called cpu1 with 3 instances of flavor plus-24-12 with a volume size of 248GB.

terraform_variables:
  additional_worker_groups:
    "cpu1":
      flavor: "plus-24-12"
      count: 3
      volume_size_gb: 248

Please note that you can’t use names master, infra, or worker for additional worker groups. We prohibit these names to ensure there are no collisions between the generated nodes names for different worker groups.
Key Default Description

count

``

(Required) The number of worker nodes in this group

flavor

``

(Required) Type of the worker node VMs

volume_size_gb

worker_volume_size_gb

Worker boot volume size in GBs. Defaults to worker_volume_size_gb.

We currently don’t provide support for any of the following configurations:

  • flavor = flex-*

  • flavor smaller than plus-16-4.

Example

parameters:
  openshift4_terraform:
    terraform_variables:
      root_disk_size: 128
      worker_count: 4
      worker_flavor: "plus-16-4"
      worker_volume_size_gb: 512
      additional_worker_groups:
        "cpu1":
          flavor: "plus-24-12"
          count: 3