Feature Overview (aka. Goal Summary)  

Customers have requested the ability to have the ability to apply tolerations to the HCP control plane pods. This provides the flexibility to have the HCP pods scheduled to nodes with taints applied to them that are not currently tolerated by default.

API 

Add new field to HostedCluster. hc.Spec.Tolerations

Tolerations   []corev1.Toleration `json:"tolerations,omitempty"` 

Implementation

In support/config/deployment.go, add hc.spec.tolerations from hc when generating the default config. This will cause the toleration to naturally get spread to the deployments and statefulsets.

CLI

Add new cli argument called –tolerations to the hcp cli tool during cluster creation. This argument should be able to be set multiple times. The syntax of the field should follow the convention set by the kubectl client tool when setting a taint on a node.

For example, the kubectl client tool can be used to set the following taint on a node.

kubectl taint nodes node1 key1=value1:NoSchedule

And then the hcp cli tool should be able to add a toleration for this taint during creation with the following cli arg.

hcp cluster create kubevirt –toleration “key1=value1:noSchedule” …

Goals (aka. expected user outcomes)

• Support for customer defined tolerations for HCP pods

  Requirements (aka. Acceptance Criteria):

A list of specific needs or objectives that a feature must deliver in order to be considered complete.  Be sure to include nonfunctional requirements such as security, reliability, performance, maintainability, scalability, usability, etc.  Initial completion during Refinement status.

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Anyone reviewing this Feature needs to know which deployment configurations that the Feature will apply to (or not) once it's been completed.  Describe specific needs (or indicate N/A) for each of the following deployment scenarios. For specific configurations that are out-of-scope for a given release, ensure you provide the OCPSTRAT (for the future to be supported configuration) as well.

Use Cases (Optional):

Include use case diagrams, main success scenarios, alternative flow scenarios.  Initial completion during Refinement status.

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Questions to Answer (Optional):

Include a list of refinement / architectural questions that may need to be answered before coding can begin.  Initial completion during Refinement status.

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Out of Scope

High-level list of items that are out of scope.  Initial completion during Refinement status.

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Background

Provide any additional context is needed to frame the feature.  Initial completion during Refinement status.

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Customer Considerations

Provide any additional customer-specific considerations that must be made when designing and delivering the Feature.  Initial completion during Refinement status.

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Documentation Considerations

Provide information that needs to be considered and planned so that documentation will meet customer needs.  If the feature extends existing functionality, provide a link to its current documentation. Initial completion during Refinement status.

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Interoperability Considerations

Which other projects, including ROSA/OSD/ARO, and versions in our portfolio does this feature impact?  What interoperability test scenarios should be factored by the layered products?  Initial completion during Refinement status.

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