new-trial-kind.md

Document about how to support a new Kubernetes resource in Katib trial

Update the supported list

First, GetSupportedJobList in common.go needs to be updated.

func GetSupportedJobList() []schema.GroupVersionKind {
	supportedJobList := []schema.GroupVersionKind{
		{
			Group:   "batch",
			Version: "v1",
			Kind:    "Job",
		},
		{
			Group:   "kubeflow.org",
			Version: "v1",
			Kind:    "TFJob",
		},
		{
			Group:   "kubeflow.org",
			Version: "v1",
			Kind:    "PyTorchJob",
		},
	}
	return supportedJobList
}

In this function, we define the Kubernetes GroupVersionKind that are supported in Katib. If you want to add a new kind, please append the supportedJobList.

Update logic about status update

GetDeployedJobStatus in trial_controller_util.go needs to be updated.

It is used to determine if the trial is completed (Succeeded or Failed).

Update logic about pod injection webhook

Add logic to support mutating container

isWorkerContainer in inject_webhook.go needs to be updated.

func isWorkerContainer(jobKind string, index int, c v1.Container) bool {
	switch jobKind {
	case BatchJob:
		if index == 0 {
			// for Job worker, the first container will be taken as worker container,
			// katib document should note it
			return true
		}
	case TFJob:
		if c.Name == TFJobWorkerContainerName {
			return true
		}
	case PyTorchJob:
		if c.Name == PyTorchJobWorkerContainerName {
			return true
		}
	default:
		log.Info("Invalid Katib worker kind", "JobKind", jobKind)
		return false
	}
	return false
}

The function is used to determine which container in the job is the actual main container.

Add logic about how to determine the master pod

In Katib, we only inject metrics collector sidecar into the master pod (See metrics-collector.md for more details). Thus we need to update the JobRoleMap in const.go.

var JobRoleMap = map[string][]string{
	"TFJob":      {JobRoleLabel, TFJobRoleLabel},
	"PyTorchJob": {JobRoleLabel, PyTorchJobRoleLabel},
	"Job":        {},
}