scheduling-webhook: hypershift image builds in memory-based storage

Author: sjenning

cmd/ci-scheduling-webhook/mutation.go

@@ -201,6 +201,12 @@ func mutatePod(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	if podClass == PodClassBuilds &&
+		strings.HasPrefix(podName, "hypershift") &&
+		strings.HasSuffix(podName, "amd64-build") {
+		podClass = PodClassBuildsTmpfs
+	}
+
 	if podClass != PodClassNone {
 		profile("classified request")
 
@@ -347,6 +353,23 @@ func mutatePod(w http.ResponseWriter, r *http.Request) {
 			addPatchEntry("add", "/spec/affinity", unstructuredAffinity)
 		}
 
+		if podClass == PodClassBuildsTmpfs {
+			// Iterate over pod volumes and set medium to memory for container-storage-root and container-storage-run volumes
+			for i, volume := range pod.Spec.Volumes {
+				if volume.Name == "container-storage-root" || volume.Name == "container-storage-run" {
+					if volume.EmptyDir != nil {
+						volume.EmptyDir.Medium = corev1.StorageMediumMemory
+						unstructuredEmptyDir, err := runtime.DefaultUnstructuredConverter.ToUnstructured(volume.EmptyDir)
+						if err != nil {
+							writeHttpError(500, fmt.Errorf("error decoding emptydir to unstructured data: %w", err))
+							return
+						}
+						addPatchEntry("replace", fmt.Sprintf("/spec/volumes/%v/emptydir", i), unstructuredEmptyDir)
+					}
+				}
+			}
+		}
+
 		// There is currently an issue with cluster scale up where pods are stacked up, unschedulable.
 		// A machine is provisioned. As soon as the machine is provisioned, pods are scheduled to the
 		// node and they begin to run before DNS daemonset pods can successfully configure the pod.

cmd/ci-scheduling-webhook/prioritization.go

@@ -30,11 +30,12 @@ import (
 type PodClass string
 
 const (
-	PodClassBuilds    PodClass = "builds"
-	PodClassTests     PodClass = "tests"
-	PodClassLongTests PodClass = "longtests"
-	PodClassProwJobs  PodClass = "prowjobs"
-	PodClassNone      PodClass = ""
+	PodClassBuilds      PodClass = "builds"
+	PodClassBuildsTmpfs PodClass = "builds-tmpfs"
+	PodClassTests       PodClass = "tests"
+	PodClassLongTests   PodClass = "longtests"
+	PodClassProwJobs    PodClass = "prowjobs"
+	PodClassNone        PodClass = ""
 
 	// MachineDeleteAnnotationKey When a machine is annotated with this and the machineset is scaled down,
 	// it will target machines with this annotation to satisfy the change.