Add docs on active redirection

README.md

@@ -7,6 +7,7 @@
 - Cluster management through HTTP API
 - Automatic failover for both master and replica
 - Fast scaling
+- Both cluster-mode clients and non-cluster-mode clients.
 - String value compression
 
 Any storage system implementing redis protocol could also somehow work with undermoon,
@@ -200,6 +201,7 @@ $ curl -XDELETE http://localhost:7799/api/v2/proxies/meta/server_proxy3:6003
 - [Chunk](./docs/chunk.md)
 - [Slot Migration](./docs/slots_migration.md)
 - [Memory Broker Replica](./docs/mem_broker_replica.md)
+- [Configure to support non-cluster-mode clients](./docs/active_redirection.md)
 
 ## API
 - [Proxy UMCTL command](./docs/meta_command.md)

docs/active_redirection.md

@@ -0,0 +1,16 @@
+# Active Redirection Mode
+When server proxies run in `active redirection` mode,
+they will expose themselves in a single Redis client protocol.
+Clients don't need to support [Redis Cluster Protocol](./redis_cluster_protocol.md).
+
+## Enable Active Redirection
+Inside the server proxy config file`server-proxy.toml`,
+set `active_redirection` to `true`,
+or use environment variable `UNDERMOON_ACTIVE_REDIRECTION=true`.
+
+## How it works?
+When `active redirection` mode is enabled,
+a server proxy will automatically redirect the requests to other server proxies.
+Then if needed, other server proxies will keep redirecting the requests
+until they find the owner or exceed maximum redirection limit
+set by `max_redirections` in server proxy config file.