feat(ELB): add params to elb member resource (#6555)

Author: houpeng80

docs/resources/elb_member.md

@@ -46,9 +46,9 @@ The following arguments are supported:
 * `address` - (Required, String, ForceNew) The IP address of the member to receive traffic from the load balancer.
   Changing this creates a new member.
 
-* `protocol_port` - (Optional, Int, ForceNew) The port on which to listen for client traffic. It must be set to `0`
-  for gateway load balancers with IP backend server groups associated. It can be left blank because it does not take
-  effect if `any_port_enable` is set to **true** for a backend server group. Changing this creates a new member.
+* `protocol_port` - (Optional, Int) The port on which to listen for client traffic. It must be set to `0` for gateway
+  load balancers with IP backend server groups associated. It can be left blank because it does not take effect if
+  `any_port_enable` is set to **true** for a backend server group.
 
 * `weight` - (Optional, Int)  A positive integer value that indicates the relative portion of traffic that this member
   should receive from the pool. For example, a member with a weight of 10 receives five times as much traffic as a
@@ -60,6 +60,52 @@ In addition to all arguments above, the following attributes are exported:
 
 * `id` - The unique ID for the member.
 
+* `instance_id` - The ID of the instance associated with the backend server. If this parameter is left blank, the backend
+  server is not a real device. It may be an IP address.
+
+* `ip_version` - The IP version supported by the backend server. The value can be **v4 (IPv4)** or **v6 (IPv6)**, depending
+  on the value of address returned by the system.
+
+* `member_type` - The type of the backend server. The value can be:
+  + **ip**: IP as backend servers
+  + **instance**: ECSs used as backend servers
+
+* `operating_status` - The health status of the backend server if `listener_id` under `status` is not specified. The value
+  can be:
+  + **ONLINE**: The backend server is running normally.
+  + **NO_MONITOR**: No health check is configured for the backend server group to which the backend server belongs.
+  + **OFFLINE**: The cloud server used as the backend server is stopped or does not exist.
+
+* `reason` - Why health check fails.
+  The [reason](#reason_struct) structure is documented below.
+
+* `status` - The health status of the backend server if `listener_id` under status is specified. If `listener_id` under
+  `status` is not specified, `operating_status` of member takes precedence.
+  The [status](#status_struct) structure is documented below.
+
+* `created_at` - The time when the backend server was added. The format is **yyyy-MM-dd'T'HH:mm:ss'Z' (UTC time)**.
+
+* `updated_at` - The time when the backend server was updated. The format is **yyyy-MM-dd'T'HH:mm:ss'Z' (UTC time)**.
+
+<a name="reason_struct"></a>
+The `reason` block supports:
+
+* `expected_response` - The code of the health check failures.
+
+* `healthcheck_response` - The expected HTTP status code.
+
+* `reason_code` - The returned HTTP status code in the response.
+
+<a name="status_struct"></a>
+The `status` block supports:
+
+* `listener_id` - The listener ID.
+
+* `operating_status` - The health status of the backend server.
+
+* `reason` - Why health check fails.
+  The [reason](#reason_struct) structure is documented below.
+
 ## Timeouts
 
 This resource provides the following timeouts configuration options: