Allow to provision the priorityclass using the same helm chart

[tback]

Is your feature request related to a problem? Please describe.
Yes: I want to ensure that fluent-bit is always running on my nodes. I want to create the priorityClass to be used alongside the fluent-bit deployment. Log shipping is essential for me, so I accept that it removes other pods from the host.

Describe the solution you'd like
I'd like an extraObjects entry in the values file (and a template to roll it out)

Describe alternatives you've considered
I could rollout the priority separately which is an additional effort.

[coderabbitai]

A summary of the changes CodeRabbit can apply:

• Add an extraObjects: [] entry to values.yaml (with a PriorityClass example), create templates/extra-objects.yaml that renders each extraObjects item via tpl(toYaml .) to allow template-aware injection of arbitrary Kubernetes manifests (e.g., PriorityClass), and include HELM_CHART_PRIORITYCLASS_FEATURE.md documenting usage, examples, testing, and security considerations so the Helm chart can provision PriorityClass and other resources in a single, backward-compatible deployment.

• Add a new implementation guide (HELM_CHART_PRIORITYCLASS_FEATURE.md) that specifies adding an extraObjects: [] block to charts/fluent-bit/values.yaml, creating templates/extra-objects.yaml to render extra Kubernetes resources (e.g., PriorityClass), updating README.md with examples, adding unit/integration tests and checklist items, and documenting RBAC/changelog and repository/chart targets for implementing PriorityClass provisioning in the fluent/helm-charts repo.

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[patrick-stephens]

I think this is for the helm chart repo, not the main Fluent Bit one so will move over