docs: add kubernetes reporter daemonset

Author: moonrailgun

docker/k8s/reporter-daemonset.yaml

@@ -0,0 +1,56 @@
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: tianji-reporter
+  labels:
+    app: tianji-reporter
+spec:
+  selector:
+    matchLabels:
+      app: tianji-reporter
+  template:
+    metadata:
+      labels:
+        app: tianji-reporter
+    spec:
+      containers:
+        - name: reporter
+          image: moonrailgun/tianji:latest
+          args:
+            - /usr/local/bin/tianji-reporter
+            - --url=$(TIANJI_SERVER_URL)
+            - --workspace=$(TIANJI_WORKSPACE_ID)
+            - --name=$(NODE_NAME)
+          env:
+            - name: NODE_NAME
+              valueFrom:
+                fieldRef:
+                  fieldPath: spec.nodeName
+            - name: TIANJI_SERVER_URL
+              value: "http://tianji.example.com"
+            - name: TIANJI_WORKSPACE_ID
+              value: "<your_workspace_id>"
+          volumeMounts:
+            - name: proc
+              mountPath: /proc
+              readOnly: true
+            - name: sys
+              mountPath: /sys
+              readOnly: true
+            - name: rootfs
+              mountPath: /rootfs
+              readOnly: true
+          securityContext:
+            privileged: true
+      hostNetwork: true
+      hostPID: true
+      volumes:
+        - name: proc
+          hostPath:
+            path: /proc
+        - name: sys
+          hostPath:
+            path: /sys
+        - name: rootfs
+          hostPath:
+            path: /

website/docs/server-status/kubernetes/_category_.json

@@ -0,0 +1,4 @@
+{
+  "label": "Kubernetes",
+  "position": 10
+}

website/docs/server-status/kubernetes/reporter-daemonset.md

@@ -0,0 +1,27 @@
+---
+sidebar_position: 1
+---
+
+# Deploy Reporter as DaemonSet
+
+If you are running Tianji inside Kubernetes, you may want to collect each node's
+system metrics. The easiest way is to run `tianji-reporter` as a DaemonSet so it
+runs on every node.
+
+1. Edit `docker/k8s/reporter-daemonset.yaml` and replace the `TIANJI_SERVER_URL` and `TIANJI_WORKSPACE_ID` values with your actual server address and workspace ID.
+2. Apply the manifest:
+
+```bash
+kubectl apply -f docker/k8s/reporter-daemonset.yaml
+```
+
+Every node will start a `tianji-reporter` container which reports system
+statistics to your Tianji instance. You can check the logs of a specific pod to
+ensure it works:
+
+```bash
+kubectl logs -l app=tianji-reporter -f
+```
+
+Once the pods are running, the **Servers** page in Tianji will list your
+Kubernetes nodes just like regular machines.

website/docs/server-status/server-status-reporter.md

@@ -45,6 +45,11 @@ curl -o- https://tianji.example.com/serverStatus/xxxxxxxxxxxxxxxxxxx/install.sh?
 
 The main change is to append `-s uninstall` to your install command.
 
+## Kubernetes
+
+If your servers are running in a Kubernetes cluster, you can deploy the reporter as a DaemonSet so each node reports metrics automatically. See [Deploy Reporter as DaemonSet](./kubernetes/reporter-daemonset.md) for details.
+
+
 ## Q&A
 
 ### How to check tianji reporter service log?