antctl mc doc

Signed-off-by: zbangqi <[email protected]>

docs/antctl.md

@@ -33,6 +33,7 @@ running in three different modes:
   - [Flow Aggregator commands](#flow-aggregator-commands)
     - [Dumping flow records](#dumping-flow-records)
     - [Record metrics](#record-metrics)
+  - [Multi Cluster commands](#multi-cluster-commands)
 <!-- /toc -->
 
 ## Installation
@@ -626,3 +627,28 @@ Example outputs of record metrics:
 RECORDS-EXPORTED RECORDS-RECEIVED FLOWS EXPORTERS-CONNECTED
 46               118              7     2      
 ```
+
+### Multi-Cluster commands
+
+Starting with version 1.6.0, Antrea supports the `antctl mc` commands, which can collect information from multicluster cluster. 
+This information is useful when tryting to troubleshoot issues in
+- `antctl` `mc` `get clusterset` (or `get clustersets`) command can print all
+ClusterSets, a specified Clusterset, or ClusterSets in a specified
+Namespace.
+- `antctl` `mc` `get resourceimport` (or `get resourceimports`, `get ri`) command can print all
+ResourceImports, a specified ResourceImport, or ResourceImports in a specified
+Namespace.
+- `antctl` `mc` `get resourceexport` (or `get resourceexports`, `get re`) command can print all
+ResourceExports, a specified ResourceExport, ResourceExports in a specified
+Namespace, or ResourceExports in a specific cluster.
+
+Using the `json` or `yaml` antctl output format can print more information of
+ClusterSet, ResourceImport, and ResourceExport, than using the default table
+output format. The `NAME` of a control plane NetworkPolicy is the UID of its source
+NetworkPolicy.
+
+```bash
+antctl mc get clusterset [NAME] [-n NAMESPACE] [-o yaml] [--ALLNAMESPACES]
+antctl mc get resourceimport [NAME] [-n NAMESPACE] [-o yaml] [--ALLNAMESPACES]
+antctl mc get resourceexport [NAME] [-n NAMESPACE] [-clusterid CLUSTERID] [-o yaml] [--ALLNAMESPACES]
+```