Name nginx_http_upstream_check_module - support upstream health check with Nginx Synopsis http { upstream cluster { # simple round-robin server 192.168.0.1:80; server 192.168.0.2:80; check interval=5000 rise=1 fall=3 timeout=4000; #check interval=3000 rise=2 fall=5 timeout=1000 type=ssl_hello; #check interval=3000 rise=2 fall=5 timeout=1000 type=http; #check_http_send "HEAD / HTTP/1.0\r\n\r\n"; #check_http_expect_alive http_2xx http_3xx; } server { listen 80; location / { proxy_pass http://cluster; } location /status { check_status; access_log off; allow SOME.IP.ADD.RESS; deny all; } } } Description Add the support of health check with the upstream servers. Directives check syntax: *check interval=milliseconds [fall=count] [rise=count] [timeout=milliseconds] [default_down=true|false] [type=tcp|http|ssl_hello|mysql|ajp|fastcgi]* default: *none, if parameters omitted, default parameters are interval=30000 fall=5 rise=2 timeout=1000 default_down=true type=tcp* context: *upstream* description: Add the health check for the upstream servers. The parameters' meanings are: * *interval*: the check request's interval time. * *fall*(fall_count): After fall_count check failures, the server is marked down. * *rise*(rise_count): After rise_count check success, the server is marked up. * *timeout*: the check request's timeout. * *default_down*: set initial state of backend server, default is down. * *port*: specify the check port in the backend servers. It can be different with the original servers port. Default the port is 0 and it means the same as the original backend server. * *type*: the check protocol type: 1. *tcp* is a simple tcp socket connect and peek one byte. 2. *ssl_hello* sends a client ssl hello packet and receives the server ssl hello packet. 3. *http* sends a http request packet, receives and parses the http response to diagnose if the upstream server is alive. 4. *mysql* connects to the mysql server, receives the greeting response to diagnose if the upstream server is alive. 5. *ajp* sends a AJP Cping packet, receives and parses the AJP Cpong response to diagnose if the upstream server is alive. 6. *fastcgi* send a fastcgi request, receives and parses the fastcgi response to diagnose if the upstream server is alive. check_http_send syntax: *check_http_send http_packet* default: *"GET / HTTP/1.0\r\n\r\n"* context: *upstream* description: If you set the check type is http, then the check function will sends this http packet to check the upstream server. check_http_expect_alive syntax: *check_http_expect_alive [ http_2xx | http_3xx | http_4xx | http_5xx ]* default: *http_2xx | http_3xx* context: *upstream* description: These status codes indicate the upstream server's http response is ok, the backend is alive. check_keepalive_requests syntax: *check_keepalive_requests num* default: *check_keepalive_requests 1* context: *upstream* description: The directive specifies the number of requests sent on a connection, the default vaule 1 indicates that nginx will certainly close the connection after a request. check_fastcgi_param Syntax: *check_fastcgi_params parameter value* default: see below context: *upstream* description: If you set the check type is fastcgi, then the check function will sends this fastcgi headers to check the upstream server. The default directive looks like: check_fastcgi_param "REQUEST_METHOD" "GET"; check_fastcgi_param "REQUEST_URI" "/"; check_fastcgi_param "SCRIPT_FILENAME" "index.php"; check_shm_size syntax: *check_shm_size size* default: *1M* context: *http* description: Default size is one megabytes. If you check thousands of servers, the shared memory for health check may be not enough, you can enlarge it with this directive. check_status syntax: *check_status [html|csv|json]* default: *none* context: *location* description: Display the health checking servers' status by HTTP. This directive should be set in the http block. You can specify the default display format. The formats can be `html`, `csv` or `json`. The default type is `html`. It also supports to specify the format by the request argument. Suppose your `check_status` location is '/status', the argument of `format` can change the display page's format. You can do like this: /status?format=html /status?format=csv /status?format=json At present, you can fetch the list of servers with the same status by the argument of `status`. For example: /status?format=html&status=down /status?format=csv&status=up Below it's the sample html page:

Nginx http upstream check status

Check upstream server number: 1, generation: 3

Index Upstream Name Status Rise counts Fall counts Check type Check port 0 backend 106.187.48.116:80 up 39 0 http 80 Below it's the sample of csv page: 0,backend,106.187.48.116:80,up,46,0,http,80 Below it's the sample of json page: {"servers": { "total": 1, "generation": 3, "server": [ {"index": 0, "upstream": "backend", "name": "106.187.48.116:80", "status": "up", "rise": 58, "fall": 0, "type": "http", "port": 80} ] }} Installation Download the latest version of the release tarball of this module from github () Grab the nginx source code from nginx.org (), for example, the version 1.0.14 (see nginx compatibility), and then build the source with this module: $ wget 'http://nginx.org/download/nginx-1.0.14.tar.gz' $ tar -xzvf nginx-1.0.14.tar.gz $ cd nginx-1.0.14/ $ patch -p1 < /path/to/nginx_http_upstream_check_module/check.patch $ ./configure --add-module=/path/to/nginx_http_upstream_check_module $ make $ make install Note If you use nginx-1.2.1 or nginx-1.3.0, the nginx upstream round robin module changed greatly. You should use the patch named 'check_1.2.1.patch'. If you use nginx-1.2.2+ or nginx-1.3.1+, It added the upstream least_conn module. You should use the patch named 'check_1.2.2+.patch'. If you use nginx-1.2.6+ or nginx-1.3.9+, It adjusted the round robin module. You should use the patch named 'check_1.2.6+.patch'. If you use nginx-1.5.12+, You should use the patch named 'check_1.5.12+.patch'. If you use nginx-1.7.2+, You should use the patch named 'check_1.7.2+.patch'. The patch just adds the support for the official Round-Robin, Ip_hash and least_conn upstream modu