bind.interface configuration only affects server binding, not client HTTP connections in cluster communication

### problem

##### ISSUE TYPE
* Bug Report

##### COMPONENT NAME
~~~
Cluster Communication / Management Server
~~~

##### CLOUDSTACK VERSION
~~~
4.20.1.0
main branch (current)
All versions with cluster communication feature
~~~

##### CONFIGURATION
Advanced networking, VRF/multi-homed management server configuration

##### OS / ENVIRONMENT
Linux with VRF (Virtual Routing and Forwarding) or multiple network interfaces

##### SUMMARY
The `bind.interface` configuration in server.properties only affects server-side binding (Jetty HTTP server) but is completely ignored for client-side HTTP
connections used in cluster communication. This causes cluster communication failures in VRF or multi-homed environments where management traffic should be
isolated to a specific interface.

##### STEPS TO REPRODUCE
~~~
1. Configure management server with VRF or multiple interfaces
2. Set bind.interface=192.168.100.10 in server.properties (VRF interface)
3. Set cluster.node.IP=192.168.100.10 in db.properties
4. Start CloudStack management server
5. Observe cluster communication attempts
~~~

##### EXPECTED RESULTS
~~~
- Management server binds to 192.168.100.10:8080 (server-side) ✓
- Management server binds to 192.168.100.10:9090 (cluster service) ✓
- Outbound cluster HTTP connections originate from 192.168.100.10 ✓
- Cluster communication works within the same network namespace/VRF ✓
~~~

##### ACTUAL RESULTS
~~~
- Management server binds to 192.168.100.10:8080 (server-side) ✓ (edit: actually this is not true. on clean start can't bind to vrf addr)
- Management server binds to 192.168.100.10:9090 (cluster service) ✓ (edit: actually this is not true. on clean start can't bind to vrf addr)
- Outbound cluster HTTP connections originate from default interface (10.0.1.2) ❌
- Connection timeout: "Connect to 192.168.100.10:9090 [/192.168.100.10] failed: Connection timed out"

ERROR [c.c.c.ClusterServiceServletImpl] Exception from : https://192.168.100.10:9090/clusterservice
org.apache.http.conn.ConnectTimeoutException: Connect to 192.168.100.10:9090 [/192.168.100.10] failed: Connection timed out

ss output shows asymmetric routing:
SYN-SENT [::ffff:10.0.1.2]:57104 -> [::ffff:192.168.100.10]:9090
~~~

**Root Cause**: `ClusterServiceServletImpl.getHttpClient()` creates HttpClient without source address binding configuration. The HttpClient uses system
default routing instead of respecting the configured bind.interface.

**Files Affected**:
- `framework/cluster/src/main/java/com/cloud/cluster/ClusterServiceServletImpl.java:180-183`
- `client/src/main/java/org/apache/cloudstack/ServerDaemon.java:246` (server binding works correctly)

**Suggested Fix**:
Add source interface binding to HttpClient configuration by reading bind.interface from server.properties and configuring a custom ConnectionSocketFactory
with setLocalAddress().

**Example Diff**:
```diff
--- a/framework/cluster/src/main/java/com/cloud/cluster/ClusterServiceServletImpl.java
+++ b/framework/cluster/src/main/java/com/cloud/cluster/ClusterServiceServletImpl.java
@@ -177,8 +177,26 @@ public class ClusterServiceServletImpl implements ClusterService {
.setConnectionRequestTimeout(timeout)
.setSocketTimeout(timeout).build();

+ // Read bind.interface from server.properties for source binding
+ String bindInterface = getBindInterface();
+ ConnectionSocketFactory socketFactory = new SSLConnectionSocketFactory(sslContext);
+
+ if (bindInterface != null) {
+ InetAddress localAddress = InetAddress.getByName(bindInterface);
+ socketFactory = new SSLConnectionSocketFactory(sslContext) {
+ @Override
+ public Socket connectSocket(int connectTimeout, Socket sock, HttpHost host,
+ InetSocketAddress remoteAddress, InetSocketAddress localSocketAddress,
+ HttpContext context) throws IOException {
+ sock.bind(new InetSocketAddress(localAddress, 0));
+ return super.connectSocket(connectTimeout, sock, host, remoteAddress,
+ localSocketAddress, context);
+ }
+ };
+ }
+
s_client = HttpClientBuilder.create()
.setDefaultRequestConfig(config)
- .setSSLContext(sslContext)
+ .setSSLSocketFactory(socketFactory)
.build();
}

---
P.S.: Example code provided by Claude AI assistant during issue analysis.
P.P.S: Socket binding and cluster and main http is not a vrf-aware.

### versions

cloudstack 4.20.1.0
ubuntu 25

Bắt đầu tại framework/cluster/src/main/java/com/cloud/cluster/ClusterServiceServletImpl.java:180-183 và kiểm tra getHttpClient(), sau đó so sánh hành vi của nó với việc bind máy chủ trong client/src/main/java/org/apache/cloudstack/ServerDaemon.java:246. Tái hiện cấu hình VRF hoặc nhiều interface từ issue và xác minh rằng các kết nối HTTP outbound của cluster sử dụng bind.interface đã cấu hình và giao tiếp thành công.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.