nginx: add the configuration to retrieve the metrics in prometheus

It will allow to have an idea of the load of the nginx. Unfortunately, the community version of nginx provides only global metrics, not detailed metrics per vhosts.

Example of exported statistics :

root@pergamon:~# curl 10.168.130.30:9103/metrics
# HELP nginx_connections_accepted Accepted client connections
# TYPE nginx_connections_accepted counter
nginx_connections_accepted 170
# HELP nginx_connections_active Active client connections
# TYPE nginx_connections_active gauge
nginx_connections_active 5
# HELP nginx_connections_handled Handled client connections
# TYPE nginx_connections_handled counter
nginx_connections_handled 170
# HELP nginx_connections_reading Connections where NGINX is reading the request header
# TYPE nginx_connections_reading gauge
nginx_connections_reading 0
# HELP nginx_connections_waiting Idle client connections
# TYPE nginx_connections_waiting gauge
nginx_connections_waiting 4
# HELP nginx_connections_writing Connections where NGINX is writing the response back to the client
# TYPE nginx_connections_writing gauge
nginx_connections_writing 1
# HELP nginx_http_requests_total Total http requests
# TYPE nginx_http_requests_total counter
nginx_http_requests_total 268

more info at : https://nginx.org/en/docs/http/ngx_http_stub_status_module.html#stub_status

Test Plan

• moma

diff origin/production/moma.softwareheritage.org current/moma.softwareheritage.org
*******************************************
+ Concat::Fragment[nginx-metrics-500-6666cd76f96956469e7be39d750cc7d9] =>
   parameters =>
     "content": "\n  location / {\n    index     index.html index.htm index.php;\...
     "order": 500,
     "target": "/etc/nginx/sites-available/nginx-metrics.conf"
*******************************************
+ Concat::Fragment[nginx-metrics-500-ae3b848d2daecffc635ae20b0b882d8f] =>
   parameters =>
     "content": "\n  location /metrics {\n    stub_status on;\n    index     inde...
     "order": 500,
     "target": "/etc/nginx/sites-available/nginx-metrics.conf"
*******************************************
+ Concat::Fragment[nginx-metrics-footer] =>
   parameters =>
     "content": "}\n",
     "order": "699",
     "target": "/etc/nginx/sites-available/nginx-metrics.conf"
*******************************************
+ Concat::Fragment[nginx-metrics-header] =>
   parameters =>
     "content": "# MANAGED BY PUPPET\nserver {\n  listen 127.0.0.1:9081 deferred;...
     "order": "001",
     "target": "/etc/nginx/sites-available/nginx-metrics.conf"
*******************************************
+ Concat[/etc/nginx/sites-available/nginx-metrics.conf] =>
   parameters =>
     "backup": "puppet",
     "ensure": "present",
     "ensure_newline": false,
     "force": false,
     "format": "plain",
     "group": "root",
     "mode": "0644",
     "notify": "Class[Nginx::Service]",
     "order": "alpha",
     "owner": "root",
     "path": "/etc/nginx/sites-available/nginx-metrics.conf",
     "replace": true,
     "show_diff": true,
     "tag": "nginx_config_file",
     "warn": false
*******************************************
+ Concat_file[/etc/nginx/sites-available/nginx-metrics.conf] =>
   parameters =>
     "backup": "puppet",
     "ensure_newline": false,
     "force": false,
     "format": "plain",
     "group": "root",
     "mode": "0644",
     "order": "alpha",
     "owner": "root",
     "replace": true,
     "show_diff": true,
     "tag": "_etc_nginx_sites-available_nginx-metrics.conf"
*******************************************
+ Concat_fragment[nginx-metrics-500-6666cd76f96956469e7be39d750cc7d9] =>
   parameters =>
     "content": "\n  location / {\n    index     index.html index.htm index.php;\...
     "order": 500,
     "tag": "_etc_nginx_sites-available_nginx-metrics.conf",
     "target": "/etc/nginx/sites-available/nginx-metrics.conf"
*******************************************
+ Concat_fragment[nginx-metrics-500-ae3b848d2daecffc635ae20b0b882d8f] =>
   parameters =>
     "content": "\n  location /metrics {\n    stub_status on;\n    index     inde...
     "order": 500,
     "tag": "_etc_nginx_sites-available_nginx-metrics.conf",
     "target": "/etc/nginx/sites-available/nginx-metrics.conf"
*******************************************
+ Concat_fragment[nginx-metrics-footer] =>
   parameters =>
     "content": "}\n",
     "order": "699",
     "tag": "_etc_nginx_sites-available_nginx-metrics.conf",
     "target": "/etc/nginx/sites-available/nginx-metrics.conf"
*******************************************
+ Concat_fragment[nginx-metrics-header] =>
   parameters =>
     "content": "# MANAGED BY PUPPET\nserver {\n  listen 127.0.0.1:9081 deferred;...
     "order": "001",
     "tag": "_etc_nginx_sites-available_nginx-metrics.conf",
     "target": "/etc/nginx/sites-available/nginx-metrics.conf"
*******************************************
+ File[/etc/default/prometheus-nginx-exporter] =>
   parameters =>
     "content": "# Managed by Puppet (class profile::prometheus::nginx), changes ...
     "ensure": "present",
     "group": "root",
     "mode": "0644",
     "notify": "Service[prometheus-nginx-exporter]",
     "owner": "root"
*******************************************
+ File[/etc/nginx/sites-enabled/nginx-metrics.conf] =>
   parameters =>
     "ensure": "link",
     "group": "root",
     "mode": "0644",
     "notify": "Class[Nginx::Service]",
     "owner": "root",
     "target": "/etc/nginx/sites-available/nginx-metrics.conf"
*******************************************
+ Nginx::Resource::Location[/metrics] =>
   parameters =>
     "add_header": {
     },
     "ensure": "present",
     "fastcgi_params": "/etc/nginx/fastcgi.conf",
     "flv": false,
     "index_files": [
       "index.html",
       "index.htm",
       "index.php"
     ],
     "internal": false,
     "location": "/metrics",
     "mp4": false,
     "priority": 500,
     "proxy_connect_timeout": "90s",
     "proxy_hide_header": [
    
     ],
     "proxy_ignore_header": [
    
     ],
     "proxy_pass_header": [
    
     ],
     "proxy_read_timeout": "90s",
     "proxy_send_timeout": "90s",
     "proxy_set_header": [
       "Host $host",
       "X-Real-IP $remote_addr",
       "X-Forwarded-For $proxy_add_x_forwarded_for",
       "X-Forwarded-Proto $scheme",
       "Proxy \"\""
     ],
     "rewrite_rules": [
    
     ],
     "server": "nginx-metrics",
     "ssl": false,
     "ssl_only": false,
     "stub_status": true,
     "uwsgi_params": "/etc/nginx/uwsgi_params"
*******************************************
+ Nginx::Resource::Location[nginx-metrics-default] =>
   parameters =>
     "add_header": {
     },
     "ensure": "present",
     "fastcgi_params": "/etc/nginx/fastcgi.conf",
     "flv": false,
     "index_files": [
       "index.html",
       "index.htm",
       "index.php"
     ],
     "internal": false,
     "location": "/",
     "location_allow": [
    
     ],
     "location_deny": [
    
     ],
     "mp4": false,
     "notify": "Class[Nginx::Service]",
     "priority": 500,
     "proxy_connect_timeout": "90s",
     "proxy_hide_header": [
    
     ],
     "proxy_ignore_header": [
    
     ],
     "proxy_pass_header": [
    
     ],
     "proxy_read_timeout": "90s",
     "proxy_send_timeout": "90s",
     "proxy_set_header": [
       "Host $host",
       "X-Real-IP $remote_addr",
       "X-Forwarded-For $proxy_add_x_forwarded_for",
       "X-Forwarded-Proto $scheme",
       "Proxy \"\""
     ],
     "rewrite_rules": [
    
     ],
     "server": "nginx-metrics",
     "ssl": false,
     "ssl_only": false,
     "uwsgi_params": "/etc/nginx/uwsgi_params"
*******************************************
+ Nginx::Resource::Server[nginx-metrics] =>
   parameters =>
     "add_header": {
     },
     "ensure": "present",
     "fastcgi_params": "/etc/nginx/fastcgi.conf",
     "format_log": "combined",
     "geo_mappings": {
     },
     "group": "root",
     "http2": "off",
     "index_files": [
       "index.html",
       "index.htm",
       "index.php"
     ],
     "ipv6_enable": false,
     "ipv6_listen_ip": "::",
     "ipv6_listen_options": "default ipv6only=on",
     "ipv6_listen_port": 9081,
     "listen_ip": "127.0.0.1",
     "listen_options": "deferred",
     "listen_port": 9081,
     "listen_unix_socket": "/var/run/nginx.sock",
     "listen_unix_socket_enable": false,
     "location_allow": [
    
     ],
     "location_deny": [
    
     ],
     "locations": {
       "/metrics": {
         "stub_status": true
       }
     },
     "locations_defaults": {
     },
     "maintenance": false,
     "maintenance_value": "return 503",
     "mode": "0644",
     "owner": "root",
     "proxy_connect_timeout": "90s",
     "proxy_hide_header": [
    
     ],
     "proxy_pass_header": [
    
     ],
     "proxy_read_timeout": "90s",
     "proxy_send_timeout": "90s",
     "proxy_set_header": [
       "Host $host",
       "X-Real-IP $remote_addr",
       "X-Forwarded-For $proxy_add_x_forwarded_for",
       "X-Forwarded-Proto $scheme",
       "Proxy \"\""
     ],
     "resolver": [
    
     ],
     "rewrite_non_www_to_www": false,
     "rewrite_rules": [
    
     ],
     "rewrite_www_to_non_www": false,
     "server_name": [
       "127.0.0.1",
       "localhost"
     ],
     "spdy": "off",
     "ssl": false,
     "ssl_listen_option": true,
     "ssl_port": 443,
     "ssl_redirect": false,
     "ssl_stapling": false,
     "ssl_stapling_verify": false,
     "ssl_verify_client": "on",
     "string_mappings": {
     },
     "use_default_location": true,
     "uwsgi_params": "/etc/nginx/uwsgi_params"
*******************************************
+ Package[prometheus-nginx-exporter] =>
   parameters =>
     "ensure": "present",
     "notify": "Service[prometheus-nginx-exporter]"
*******************************************
+ Profile::Prometheus::Export_scrape_config[nginx] =>
   parameters =>
     "job": "nginx",
     "labels": {
     },
     "target": "192.168.100.31:9103"
*******************************************
+ Service[prometheus-nginx-exporter] =>
   parameters =>
     "enable": true,
     "ensure": "running"
*******************************************

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Migrated from D7075 (view on Phabricator)