Kubernetes support

* Total CPU and Memory usage for the entire cluster
* Total CPU and Memory usage for kubernetes pods
* Service discovery via annotations on ingress
* No storage stats yet
* No network stats yet

src/pages/api/kubernetes/status/[...service].js

@@ -0,0 +1,42 @@
+import { CoreV1Api } from "@kubernetes/client-node";
+
+import getKubeConfig from "../../../../utils/config/kubernetes";
+
+export default async function handler(req, res) {
+  const APP_LABEL =  "app.kubernetes.io/name";
+  const { service } = req.query;
+
+  const [namespace, appName] = service;
+  if (!namespace && !appName) {
+    res.status(400).send({
+      error: "kubernetes query parameters are required",
+    });
+    return;
+  }
+  const labelSelector = `${APP_LABEL}=${appName}`;
+
+  try {
+    const kc = getKubeConfig();
+    const coreApi = kc.makeApiClient(CoreV1Api);
+    const podsResponse = await coreApi.listNamespacedPod(namespace, null, null, null, null, labelSelector);
+    const pods = podsResponse.body.items;
+
+    if (pods.length === 0) {
+      res.status(200).send({
+        error: "not found",
+      });
+      return;
+    }
+
+    // at least one pod must be in the "Running" phase, otherwise its "down"
+    const runningPod = pods.find(pod => pod.status.phase === "Running");
+    const status = runningPod ? "running" : "down";
+    res.status(200).json({
+      status
+    });
+  } catch {
+    res.status(500).send({
+      error: "unknown error",
+    });
+  }
+}