sidecar

Filer-Active-Active-cross-cluster-continuous-synchronization.md

@@ -22,6 +22,38 @@ weed filer.sync -a <filer1_host>:<filer1_port> -b <filer2_host>:<filer2_port> -i
 
 At the beginning, it will bootstrap from the beginning of time, or resume from the last replication checkpoint. Later, it will just run continuously and persist checkpoints periodically.
 
+## On Kubernetes with the SeaweedFS Operator
+
+If you are running SeaweedFS on Kubernetes via the [SeaweedFS Operator](https://github.com/seaweedfs/seaweedfs-operator), you can run `weed filer.sync` as a sidecar inside the filer pod itself, so it shares the pod's lifecycle and dials the local filer over loopback. Each `ComponentSpec` exposes a `sidecars` field that accepts arbitrary `v1.Container` entries.
+
+```yaml
+apiVersion: seaweed.seaweedfs.com/v1
+kind: Seaweed
+metadata:
+  name: prod
+spec:
+  image: chrislusf/seaweedfs:latest
+  master:
+    replicas: 3
+  volume:
+    replicas: 3
+    requests:
+      storage: 100Gi
+  filer:
+    replicas: 2
+    sidecars:
+      - name: filer-sync
+        image: chrislusf/seaweedfs:latest
+        command:
+          - weed
+          - filer.sync
+          - -a=localhost:8888
+          - -b=remote-filer.dr.svc.cluster.local:8888
+          - -isActivePassive
+```
+
+The sidecar runs alongside every filer replica. For active-passive replication you typically want a single sync process — pin the sidecar to one replica with a separate single-replica filer, or run `filer.sync` as its own `Deployment` instead.
+
 ## How it works?
 
 Each filer has its own local change logs. `weed filer.sync` will read the logs and replay them in the other cluster.