Dedicated Hosts for Virtual Server Instances

Key Considerations

Following are the key factors to deploy the dedicated host:

• This offering supports only static compute nodes on dedicated hosts.

• The number and profile names of dedicated hosts are determined by the worker_node_instance_type parameter.

• The current solution supports a single instance profile type from any of the supported families: bx2, cx2, mx2, third-generation, and so on.

For more information, go to Profiles.

Enabling a Dedicated Host

To enable a dedicated host, set the enable_dedicated_host parameter to true (default: false). Once enabled, all the static worker nodes are automatically attached to the same dedicated host.

Limitations

1. Single Profile Requirement

   • When enable_dedicated_host is set to true, you must specify only one profile in worker_node_instance_type parameter.

   • If more than one profile is provided, an error is displayed:

   Error Example:

   Error: Invalid value for variable
   │
   │ on terraform.tfvars line 82:
   │ 82: enable_dedicated_host = true
   │ ├────────────────
   │ │ var.enable_dedicated_host is true
   │ │ var.worker_node_instance_type is list of object with 2 elements
   │
   │ When 'enable_dedicated_host' is true, only one profile should be specified in 'worker_node_instance_type'.
   │
   │ This was checked by the validation rule at variables.tf:688,3-13.
   

2. Supported Profiles - If a single profile from bx2, cx2, mx2, cx2d, mx2d, or bx2d is specified, then the dedicated host is created from the same family and all the worker nodes are assigned to it.

3. Third-Generation Profile Limitation:

• Third-generation profiles like mx3d, cx3d, and bx3d are only available in specific regions (Dallas, Frankfurt, Toronto, Madrid).

• Deploying an unsupported profile in a different region results in a failure during the planning or early deployment stage.

  Error Example:

  If a profile "bx3d" is provided on us-east, then the build fails at planning or early stage of deployment stating that this profile is not supported.

  Error: Invalid index
  │
  │ on locals.tf line 316, in locals:
  │ 316: dh_profile = var.enable_dedicated_host ? local.dh_profiles[local.dh_profile_index] : null
  │ ├────────────────
  │ │ local.dh_profile_index is "Profile class bx3d for dedicated hosts does not exist in us-east.  Check available class with ibmcloud target -r us-east; ibmcloud is dedicated-host-profiles and retry with another worker_node_instance_type."
  │ │ local.dh_profiles is empty tuple
  │
  │ The given key does not identify an element in this collection value: a number is required.
  

Benefits

Following are the benefits of a dedicated host:

• Consistent and High Performance – Ideal for long-running workloads with demanding performance needs.

• Enhanced Workload Management – Provides better control over virtual server instance placement and resource allocation.

• High Security and Compliance – Ensures physical isolation of workloads, making it suitable for compliance-driven industries with strict data isolation and residency requirements.

Before you begin

Before you begin, make sure to complete the steps from Before you begin deploying topic.

Configuring dedicated host deployment values

Define the following variable to enable a dedicated host on an LSF cluster:

For more information about dedicated host, go to Creating dedicated hosts and groups.