+
−
+
−=======
+
− monit
+
−=======
+
−.. contents::
+
−   :local:
+
−
+
−Official docs
+
−=============
+
−
+
−https://mmonit.com/monit/documentation/monit.html
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−  Main docs.
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−https://mmonit.com/wiki/Monit/ConfigurationExamples
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−  Real-world configuration examples.
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−https://mmonit.com/wiki/Monit/FAQ
+
−  FAQ
+
−
+
−Debugging monit
+
−===============
+
−
+
−Run standalone::
+
−
+
−  monit -c /path/to/monitrc
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−
+
−Check syntax::
+
−
+
−  monit -t
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−  monit -t -c /path/to/monitrc
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−
+
−Override log file location in config::
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−
+
−  set log /var/log/monit.log
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−
+
−or with CLI option::
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−
+
−  monit -l /var/log/monit.log
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−
+
−Do not go into background::
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−
+
−  monit -I
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−
+
−Make verbose output::
+
−
+
−  monit -v
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−  monit -vv
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−
+
−Full length commant may look like::
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−
+
−  sudo monit -v status
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−  sudo monit -Iv validate
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−  sudo monit -Ivv -c /path/to/monitrc
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−
+
−To debug start/stop scripts write wrapper that redirects STDIO to file::
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−
+
−  #/bin/sh
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−  exec 1>my.log
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−  exec 2>my.log
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−  echo "$@"
+
−  exec "$@"
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−
+
−Limiting server to ``localhost``::
+
−
+
−  set httpd port 2812
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−    use address localhost
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−    allow localhost
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−    allow admin:monit
+
−
+
−Monit modes
+
−===========
+
−
+
−* In ``active`` mode (the default), Monit will pro-actively monitor a service and in case of
+
−  problems raise alerts and/or restart the service.
+
−* In ``passive`` mode, Monit will passively monitor a service and will raise alerts, but will not
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−  try to fix a problem by executing start, stop or restart.
+
−* In ``manual`` mode, Monit will enter active mode only if a service was started via Monit.
+
−
+
−Example::
+
−
+
−  check process App with pidfile /var/run/app.pid
+
−    start program = "/usr/bin/app start"
+
−    stop program = "/usr/bin/app stop"
+
−    mode passive
+
−
+
−Alerting
+
−========
+
−::
+
−
+
−  check process memcached with match memcached
+
−    start program = "/usr/bin/systemctl start memcached"
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−    stop program = "/usr/bin/systemctl stop memcached"
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−    if failed host 127.0.0.1 port 11211 protocol MEMCACHE then restart
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−    if cpu > 70% for 2 cycles then alert
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−    if cpu > 98% for 5 cycles then restart
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−    if 2 restarts within 3 cycles then timeout
+
−
+
−  check process myapp with pidfile /run/myapp.pid
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−    if does not exist then alert
+
−
+
−  check filesystem Ubuntu with path /dev/sda1
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−    if space usage > 90% then alert
+
−  check filesystem Home with path /dev/sda3
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−    if space usage > 90% then alert
+
−
+
−  check host app_name with address 127.0.0.1
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−    start "/sbin/start app_name"
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−    stop "/sbin/stop app_name"
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−    if failed port 80 protocol HTTP
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−      request /ok
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−      with timeout 5 seconds
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−      then restart
+
−
+
−Running monit by systemd
+
−========================
+
−::
+
−
+
−  [Unit]
+
−  Description=Pro-active monitoring utility for unix systems
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−  After=network.target
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−  Documentation=man:monit(1) https://mmonit.com/wiki/Monit/HowTo
+
−
+
−  [Service]
+
−  Type=simple
+
−  KillMode=process
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−  ExecStart=/usr/local/bin/monit -I
+
−  ExecStop=/usr/local/bin/monit quit
+
−  ExecReload=/usr/local/bin/monit reload
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−  Restart = on-abnormal
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−  StandardOutput=null
+
−
+
−  [Install]
+
−  WantedBy=multi-user.target
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−
+
−https://mmonit.com/wiki/Monit/Systemd
+
−  Official docs.
+
−
+
−Monitor systemd process
+
−=======================
+
−
+
−With pid-file::
+
−
+
−  check process nginx with pidfile /var/run/nginx.pid
+
−    start program = "/bin/systemctl start nginx"
+
−    stop program = "/bin/systemctl stop nginx"
+
−
+
−If process without pid-file::
+
−
+
−  check program MyApp with path "systemctl --quiet is-active MyApp"
+
−    if status != 0 then ...
+
−
+
−There is a way to tell systemd to create pid-file if process doesn't to it itself::
+
−
+
−  ExecStartPost=/bin/sh -c "echo $MAINPID > /run/myapp.pid"
+
−
+
−By matching program name::
+
−
+
−  check process MyApp matching 'myapp.*'
+
−     start program = /bin/app
+
−     stop program = something..
+
−
+
−Can systemd replace monit?
+
−==========================
+
−
+
−No. Systemd has only basic check if process is running. Imaging that process is stuck. You need some
+
−active probes, like HTTP health endpoint.
+
−
+
−Systemd has limited capabilities for notifying with ``OnFailure``::
+
−
+
−  [Service]
+
−  Restart=always
+
−  RestartSecs=30
+
−
+
−  [Unit]
+
−  OnFailure=...
+
−
+
−Reverse proxy for monit
+
−=======================
+
−
+
−Ngnix::
+
−
+
−  server {
+
−    listen   80;
+
−    server_name  my.server.name;
+
−    location /monit/ {
+
−      allow 127.0.0.1;
+
−      allow 192.0.0.0/8;
+
−      deny all;
+
−
+
−      proxy_pass http://127.0.0.1:2812;
+
−      proxy_set_header Host $host;
+
−      rewrite ^/monit/(.*) /$1 break;
+
−      proxy_ignore_client_abort on;
+
−    }
+
−  }
+
−