Introduce scale from zero annotations module

Author: odvarkadaniel

pkg/util/machineset/util.go

@@ -0,0 +1,92 @@
+package util
+
+import (
+	"errors"
+)
+
+const (
+	// Deprecated OpenShift introduced annotations for scaling from zero.
+	CpuKeyDeprecated      = "machine.openshift.io/vCPU"
+	MemoryKeyDeprecated   = "machine.openshift.io/memoryMb"
+	GpuCountKeyDeprecated = "machine.openshift.io/GPU"
+	MaxPodsKeyDeprecated  = "machine.openshift.io/maxPods"
+
+	// Upstream preferred annotations for scaling from zero.
+	CpuKey      = "capacity.cluster-autoscaler.kubernetes.io/cpu"
+	MemoryKey   = "capacity.cluster-autoscaler.kubernetes.io/memory"
+	GpuTypeKey  = "capacity.cluster-autoscaler.kubernetes.io/gpu-type"
+	GpuCountKey = "capacity.cluster-autoscaler.kubernetes.io/gpu-count"
+	MaxPodsKey  = "capacity.cluster-autoscaler.kubernetes.io/maxPods"
+
+	GpuNvidiaType = "nvidia.com/gpu"
+)
+
+// This module's intended use is to perform changes and basic checks
+// to scale from zero annotations on MachineSets. Example use of the module:
+//
+// ann := machineSet.Annotations
+// ann = SetCpuAnnotation(ann, 10)
+// ann = SetMemoryAnnotation(ann, 10)
+// if isScaleFromZeroAnnotations := HasScaleFromZeroAnnotationsEnabled(ann); !isScaleFromZeroAnnotations { ... }
+
+var (
+	// errAnnotationKeyNotFound signals to the user that the selected key was not found in the MachineSet's annotations
+	errAnnotationKeyNotFound = errors.New("could not find the selected annotation key in the MachineSet's annotations")
+)
+
+// ParseMachineSetAnnotationKey parses MachineSet's annotations and look for a key
+func ParseMachineSetAnnotationKey(annotations map[string]string, key string) (string, error) {
+	if val, exists := annotations[key]; exists && key != "" {
+		return val, nil
+	}
+
+	return "", errAnnotationKeyNotFound
+}
+
+// HasScaleFromZeroAnnotationsEnabled checks that cpu and memory upstream annotations are set in a MachineSet.
+func HasScaleFromZeroAnnotationsEnabled(annotations map[string]string) bool {
+	cpu := annotations[CpuKey]
+	mem := annotations[MemoryKey]
+
+	if cpu != "" && mem != "" {
+		return true
+	}
+	return false
+}
+
+// SetCpuAnnotation sets a value for a cpu key in the annotations of a MachineSet.
+func SetCpuAnnotation(annotations map[string]string, value string) map[string]string {
+	annotations[CpuKey] = value
+
+	return annotations
+}
+
+// SetMemoryAnnotation sets a value for a mempory key in the annotations of a MachineSet.
+func SetMemoryAnnotation(annotations map[string]string, value string) map[string]string {
+	annotations[MemoryKey] = value
+
+	return annotations
+}
+
+// SetGpuCountAnnotation sets a value for a gpu count key in the annotations of a MachineSet.
+func SetGpuCountAnnotation(annotations map[string]string, value string) map[string]string {
+	annotations[GpuCountKey] = value
+
+	return annotations
+}
+
+// SetGpuTypeAnnotation sets a value for gpu type in the annotations of a MachineSet.
+// Currently, we only support nvidia as a gpu type.
+func SetGpuTypeAnnotation(annotations map[string]string, _ string) map[string]string {
+	// TODO: Once we introduce proper gpu types, this needs to be changed.
+	annotations[GpuTypeKey] = GpuNvidiaType
+
+	return annotations
+}
+
+// SetMaxPodsAnnotation sets a value for a maxPods key in the annotations of a MachineSet.
+func SetMaxPodsAnnotation(annotations map[string]string, value string) map[string]string {
+	annotations[MaxPodsKey] = value
+
+	return annotations
+}