add ha proxy documentation

hetu-docs/en/installation/deployment-ha.md

@@ -9,7 +9,7 @@ Please follow [Deploying openLooKeng Manually](./deployment.md) or [Deploying op
 
 ## Configuring HA
 
-- Create an ``etc\state-store.properties`` file inside both coordinators and workers installation directories.
+- Create an `etc\state-store.properties` file inside both coordinators and workers installation directories.
 
 
 ### State Store Properties
@@ -46,5 +46,38 @@ hetu.multiple-coordinator.enabled=true
 
 The above properties are described below:
 
--  hetu.multiple-coordinator.enabled`: Multiple coordinator mode is enabled
--  hetu.embedded-state-store.enabled`: Allow this coordinator to use embedded state store
+-  `hetu.multiple-coordinator.enabled`: Multiple coordinator mode is enabled
+-  `hetu.embedded-state-store.enabled`: Allow this coordinator to use embedded state store
+
+## HA Cluster behind Reverse Proxy
+
+To achieve the full benefit of HA, clients(ie. openLooKeng CLI, JDBC, etc) are encouraged to _not_ connect to specific coordinators directly. Instead, they should connect to multiple coordinators through some sort of _reverse proxy_, for example through a load balancer, or a Kubernetes service. This allows the client to continue to work even if a specific coordinator is not working as expected.
+
+### Reverse Proxy Requirement
+
+When the connection is made through a reverse proxy, it is required for a given client to connect to the same coordinator during the execution of a query. This is to ensure a constant heartbeat between the client and coordinator while that query is running. This can be achieved by enabling _sticky_ connections, for example, Nginx's `ip_hash`.
+
+### Configure Reverse Proxy Example (Nginx)
+
+Please include configuration below in the Nginx configuration file (ie. `nginx.conf`)
+
+```
+http {
+    ...  # Your own configuration
+    upstream backend {
+        ip_hash;
+        server <coordinator1_ip>:<coordinator1_port>;
+        server <coordinator2_ip>:<coordinator2_port>;
+        server <coordinator3_ip>:<coordinator3_port>;
+        ...
+    }
+
+    server {
+        ... # Your own configuration
+        location / {
+            proxy_pass http://backend;
+            proxy_set_header Host <nginx_ip>:<nginx_port>;
+        }
+    }
+}
+```

hetu-docs/zh/installation/deployment-ha.md

@@ -45,4 +45,37 @@ hetu.multiple-coordinator.enabled=true
 上述属性说明如下：
 
 - `hetu.multiple-coordinator.enabled`：开启了多协调节点模式。
-- `hetu.embedded-state-store.enabled`：允许此协调节点使用嵌入式状态存储。
+- `hetu.embedded-state-store.enabled`：允许此协调节点使用嵌入式状态存储。
+
+## HA及反向代理
+
+要尽可能的显示HA的优势，建议客户端(例如openLooKeng CLI, JDBC等)不直接连接特定的协调节点，而是通过反向代理连接多个协调节点，例如使用负载平衡器或者Kubernetes服务，这样即使某个协调节点无法正常工作，客户端也可以继续使用其它的协调节点。
+
+### 反向代理要求
+
+通过反向代理连接时，要求客户端在执行语句查询期间连接到同一协调器，确保在语句查询运行时客户端和协调器之间保持恒定心跳。这可以通过配置反向代理实现，例如Nginx的`ip_hash`。
+
+### 配置反向代理 (Nginx)
+
+请在Nginx配置文件中包含以下配置（nginx.conf）
+
+```
+http {
+    ...  # 用户自定义配置
+    upstream backend {
+        ip_hash;
+        server <coordinator1_ip>:<coordinator1_port>;
+        server <coordinator2_ip>:<coordinator2_port>;
+        server <coordinator3_ip>:<coordinator3_port>;
+        ...
+    }
+
+    server {
+        ... # 用户自定义配置
+        location / {
+            proxy_pass http://backend;
+            proxy_set_header Host <nginx_ip>:<nginx_port>;
+        }
+    }
+}
+```