Networking
[NSX] WebSocket 서버 구성 및 Client 접속 테스트
haewon83
2024. 6. 21. 20:48
NSX Load Balancer는 WebSocket을 위한 HTTP Upgrade를 지원합니다.
Supported Load Balancer Features
• HTTP upgrade -
For applications using HTTP upgrade such as WebSocket, the client or server requests for HTTP Upgrade, which is supported.
By default, NSX-T Data Center supports and accepts HTTPS upgrade client request using the HTTP application profile.
오늘은 이 WebSocket을 NSX Load Balancer에서 테스트 하기 위해 우선 WebSocket Server와 Client 환경을 구성하고, 접속 테스트를 진행하면서 Packet을 확인해보겠습니다.
1. WebSocket 서버 구성
아래 링크에 Python으로 작성된 Sample Code가 있습니다.
A Simple Websocket Server written in Python
https://github.com/dpallot/simple-websocket-server
테스트 환경에서는 위 Code를 이용하여 CentOS에서 WebSocket 서버 실행합니다.
※ Sample Code는 Listening Port로 8000번으로 지정되어 있으나, 변경 가능
| [root@localhost ~]# cd simple-websocket-server-master [root@localhost simple-websocket-server-master]# ls MANIFEST.in README.md setup.py SimpleWebSocketServer [root@localhost simple-websocket-server-master]# python setup.py install /usr/lib64/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: 'long_description_content_type' warnings.warn(msg) running install running build running build_py creating build creating build/lib creating build/lib/SimpleWebSocketServer copying SimpleWebSocketServer/SimpleExampleServer.py -> build/lib/SimpleWebSocketServer copying SimpleWebSocketServer/SimpleHTTPSServer.py -> build/lib/SimpleWebSocketServer copying SimpleWebSocketServer/SimpleWebSocketServer.py -> build/lib/SimpleWebSocketServer copying SimpleWebSocketServer/__init__.py -> build/lib/SimpleWebSocketServer running install_lib creating /usr/lib/python2.7/site-packages/SimpleWebSocketServer copying build/lib/SimpleWebSocketServer/SimpleExampleServer.py -> /usr/lib/python2.7/site-packages/SimpleWebSocketServer copying build/lib/SimpleWebSocketServer/SimpleHTTPSServer.py -> /usr/lib/python2.7/site-packages/SimpleWebSocketServer copying build/lib/SimpleWebSocketServer/SimpleWebSocketServer.py -> /usr/lib/python2.7/site-packages/SimpleWebSocketServer copying build/lib/SimpleWebSocketServer/__init__.py -> /usr/lib/python2.7/site-packages/SimpleWebSocketServer byte-compiling /usr/lib/python2.7/site-packages/SimpleWebSocketServer/SimpleExampleServer.py to SimpleExampleServer.pyc byte-compiling /usr/lib/python2.7/site-packages/SimpleWebSocketServer/SimpleHTTPSServer.py to SimpleHTTPSServer.pyc byte-compiling /usr/lib/python2.7/site-packages/SimpleWebSocketServer/SimpleWebSocketServer.py to SimpleWebSocketServer.pyc byte-compiling /usr/lib/python2.7/site-packages/SimpleWebSocketServer/__init__.py to __init__.pyc running install_egg_info Writing /usr/lib/python2.7/site-packages/SimpleWebSocketServer-0.1.1-py2.7.egg-info [root@localhost SimpleWebSocketServer]# pwd /root/simple-websocket-server-master/build/lib/SimpleWebSocketServer [root@localhost SimpleWebSocketServer]# ls -al total 36 drwxr-xr-x. 2 root root 115 Jun 11 04:25 . drwxr-xr-x. 3 root root 35 Jun 11 04:25 .. -rw-r--r--. 1 root root 67 Jun 11 04:23 __init__.py -rw-r--r--. 1 root root 2392 Jun 11 04:23 SimpleExampleServer.py -rw-r--r--. 1 root root 656 Jun 11 04:23 SimpleHTTPSServer.py -rw-r--r--. 1 root root 23141 Jun 11 04:23 SimpleWebSocketServer.py [root@localhost SimpleWebSocketServer]# python SimpleExampleServer.py --example=echo <running 중> |
2. Client 용 wscat 도구 설치 및 연결 테스트(Windows 환경)
https://nodejs.org/ko/download/ 에서 node download 및 설치하고, https://www.npmjs.com/package/wscat 을 참고하여 wscat 설치합니다.
설치된 wscat을 이용하여, WebSocket 서버에 연결 테스트 할 수 있습니다.
아래 테스트 예제에서 WebSocket 서버 주소는 NSX Load Balancer의 VIP입니다.
echo 모드로 WebSocket 서버를 띄웠기 때문에 Client에서 입력한 값을 그대로 다시 반환해줍니다.
| C:\Users\Administrator.AD>wscat --connect ws://172.31.1.71:8000 Connected (press CTRL+C to quit) > test < test |
3. 테스트 중 수집된 Packet
TCP-3 way Handshake > HTTP Upgrade 그리고 WebSocket Protocol을 확인할 수 있습니다.
| ## TCP 3-way Handshake 82 2024-06-12 10:59:49.159385 192.168.1.2 172.31.1.71 TCP 66 59731 → 8000 [SYN, ECN, CWR] Seq=0 Win=8192 Len=0 MSS=1460 WS=256 SACK_PERM=1 83 2024-06-12 10:59:49.164136 172.31.1.71 192.168.1.2 TCP 66 8000 → 59731 [SYN, ACK] Seq=0 Ack=1 Win=64240 Len=0 MSS=1460 SACK_PERM=1 WS=256 84 2024-06-12 10:59:49.164268 192.168.1.2 172.31.1.71 TCP 54 59731 → 8000 [ACK] Seq=1 Ack=1 Win=262656 Len=0 ## HTTP Upgrade 85 2024-06-12 10:59:49.165125 192.168.1.2 172.31.1.71 HTTP 279 GET / HTTP/1.1 Frame 85: 279 bytes on wire (2232 bits), 279 bytes captured (2232 bits) on interface \Device\NPF_{FF69533E-FA39-45AE-896D-C78BFBF04F56}, id 0 Ethernet II, Src: VMware_01:8c:58 (00:50:56:01:8c:58), Dst: VMware_a6:de:28 (00:50:56:a6:de:28) Internet Protocol Version 4, Src: 192.168.1.2, Dst: 172.31.1.71 Transmission Control Protocol, Src Port: 59731, Dst Port: 8000, Seq: 1, Ack: 1, Len: 225 Hypertext Transfer Protocol GET / HTTP/1.1\r\n [Expert Info (Chat/Sequence): GET / HTTP/1.1\r\n] [GET / HTTP/1.1\r\n] [Severity level: Chat] [Group: Sequence] Request Method: GET Request URI: / Request Version: HTTP/1.1 Sec-WebSocket-Version: 13\r\n Sec-WebSocket-Key: vwY2IBcicLkVwu3GkC9KxQ==\r\n Connection: Upgrade\r\n >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Upgrade: websocket\r\n >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits\r\n Host: 172.31.1.71:8000\r\n \r\n [Full request URI: http://172.31.1.71:8000/] [HTTP request 1/1] [Response in frame: 87] 86 2024-06-12 10:59:49.168596 172.31.1.71 192.168.1.2 TCP 60 8000 → 59731 [ACK] Seq=1 Ack=226 Win=64256 Len=0 87 2024-06-12 10:59:49.180086 172.31.1.71 192.168.1.2 HTTP 220 HTTP/1.1 101 Switching Protocols Frame 87: 220 bytes on wire (1760 bits), 220 bytes captured (1760 bits) on interface \Device\NPF_{FF69533E-FA39-45AE-896D-C78BFBF04F56}, id 0 Ethernet II, Src: VMware_a6:de:28 (00:50:56:a6:de:28), Dst: VMware_01:8c:58 (00:50:56:01:8c:58) Internet Protocol Version 4, Src: 172.31.1.71, Dst: 192.168.1.2 Transmission Control Protocol, Src Port: 8000, Dst Port: 59731, Seq: 1, Ack: 226, Len: 166 Hypertext Transfer Protocol HTTP/1.1 101 Switching Protocols\r\n [Expert Info (Chat/Sequence): HTTP/1.1 101 Switching Protocols\r\n] [HTTP/1.1 101 Switching Protocols\r\n] [Severity level: Chat] [Group: Sequence] Response Version: HTTP/1.1 Status Code: 101 [Status Code Description: Switching Protocols] Response Phrase: Switching Protocols Date: Wed, 12 Jun 2024 10:59:33 GMT\r\n Connection: upgrade\r\n Upgrade: WebSocket\r\n Sec-WebSocket-Accept: mBVob19CTSoMER2nCze2vKKC0QE=\r\n \r\n [HTTP response 1/1] [Time since request: 0.014961000 seconds] [Request in frame: 85] [Request URI: http://172.31.1.71:8000/] 88 2024-06-12 10:59:49.245554 192.168.1.2 172.31.1.71 TCP 54 59731 → 8000 [ACK] Seq=226 Ack=167 Win=262400 Len=0 ## WebSocket Echo 136 2024-06-12 10:59:56.301322 192.168.1.2 172.31.1.71 WebSocket 64 WebSocket Text [FIN] [MASKED] Frame 136: 64 bytes on wire (512 bits), 64 bytes captured (512 bits) on interface \Device\NPF_{FF69533E-FA39-45AE-896D-C78BFBF04F56}, id 0 Ethernet II, Src: VMware_01:8c:58 (00:50:56:01:8c:58), Dst: VMware_a6:de:28 (00:50:56:a6:de:28) Internet Protocol Version 4, Src: 192.168.1.2, Dst: 172.31.1.71 Transmission Control Protocol, Src Port: 59731, Dst Port: 8000, Seq: 226, Ack: 167, Len: 10 WebSocket 1... .... = Fin: True .000 .... = Reserved: 0x0 .... 0001 = Opcode: Text (1) 1... .... = Mask: True .000 0100 = Payload length: 4 Masking-Key: ac2ab0bb Masked payload Payload Line-based text data (1 lines) test 137 2024-06-12 10:59:56.313957 172.31.1.71 192.168.1.2 WebSocket 60 WebSocket Text [FIN] Frame 137: 60 bytes on wire (480 bits), 60 bytes captured (480 bits) on interface \Device\NPF_{FF69533E-FA39-45AE-896D-C78BFBF04F56}, id 0 Ethernet II, Src: VMware_a6:de:28 (00:50:56:a6:de:28), Dst: VMware_01:8c:58 (00:50:56:01:8c:58) Internet Protocol Version 4, Src: 172.31.1.71, Dst: 192.168.1.2 Transmission Control Protocol, Src Port: 8000, Dst Port: 59731, Seq: 167, Ack: 236, Len: 6 WebSocket 1... .... = Fin: True .000 .... = Reserved: 0x0 .... 0001 = Opcode: Text (1) 0... .... = Mask: False .000 0100 = Payload length: 4 Payload Line-based text data (1 lines) test |
NSX Load Balancer에서 Virtual Server에 HTTP Application Profile을 이용하면, WebSocket을 Client/Server 기반으로 사용하는데 다른 추가 설정 사항이 없음을 알 수 있습니다.