feat(supervisor): add optional memory limit overhead (#2506)

Author: nicktrn

apps/supervisor/src/env.ts

@@ -89,6 +89,7 @@ const Env = z.object({
   KUBERNETES_CPU_REQUEST_RATIO: z.coerce.number().min(0).max(1).default(0.75), // Ratio of CPU limit, so 0.75 = 75% of CPU limit
   KUBERNETES_MEMORY_REQUEST_MIN_GB: z.coerce.number().min(0).default(0),
   KUBERNETES_MEMORY_REQUEST_RATIO: z.coerce.number().min(0).max(1).default(1), // Ratio of memory limit, so 1 = 100% of memory limit
+  KUBERNETES_MEMORY_OVERHEAD_GB: z.coerce.number().min(0).optional(), // Optional memory overhead to add to the limit in GB
 
   // Placement tags settings
   PLACEMENT_TAGS_ENABLED: BoolEnv.default(false),

apps/supervisor/src/workloadManager/kubernetes.ts

@@ -25,6 +25,7 @@ export class KubernetesWorkloadManager implements WorkloadManager {
   private readonly cpuRequestRatio = env.KUBERNETES_CPU_REQUEST_RATIO;
   private readonly memoryRequestMinGb = env.KUBERNETES_MEMORY_REQUEST_MIN_GB;
   private readonly memoryRequestRatio = env.KUBERNETES_MEMORY_REQUEST_RATIO;
+  private readonly memoryOverheadGb = env.KUBERNETES_MEMORY_OVERHEAD_GB;
 
   constructor(private opts: WorkloadManagerOptions) {
     this.k8s = createK8sApi();
@@ -319,9 +320,13 @@ export class KubernetesWorkloadManager implements WorkloadManager {
   }
 
   #getResourceLimitsForMachine(preset: MachinePreset): ResourceQuantities {
+    const memoryLimit = this.memoryOverheadGb
+      ? preset.memory + this.memoryOverheadGb
+      : preset.memory;
+
     return {
       cpu: `${preset.cpu}`,
-      memory: `${preset.memory}G`,
+      memory: `${memoryLimit}G`,
     };
   }