Add init sidecar mode for k8s operator (#622)

Author: bcmmbaga

src/pages/manage/integrations/kubernetes/index.mdx

@@ -325,6 +325,35 @@ spec:
 ...
 ```
 
+### Init Sidecar Mode
+By default, the NetBird container is injected as a regular sidecar container. For workloads like Jobs and CronJobs where the pod
+should terminate after the main container completes, you can use init sidecar mode. This injects NetBird as an init container
+with `restartPolicy: Always`.
+
+To enable init sidecar mode, add the following annotation:
+
+```yaml
+netbird.io/init-sidecar: "true"
+```
+
+Below is an example of a Job using init sidecar mode:
+
+```yaml
+kind: Job
+...
+spec:
+...
+  template:
+    metadata:
+      annotations:
+        netbird.io/setup-key: app-setup-key # Must match the name of an NBSetupKey object in the same namespace
+        netbird.io/init-sidecar: "true"
+...
+    spec:
+      containers:
+...
+```
+
 ### Using Extra Labels to Access Multiple Pods Using the Same Name
 Starting with `v0.27.0`, NetBird supports extra DNS labels, allowing you to define extended DNS names for peers. This enables grouping peers under a shared DNS name and distributing traffic using DNS round-robin load balancing.