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docs/20_Checks/check_requirements.md

+# Check_requirements
+
+## Introduction
+
+**check_requirements** is a plugin to run different check to show the ability to run an application. You can these checks
+
+* Check if a process exists
+* Check an open udp or tcp port (local or on given host/ ip)
+
+You can insert a label to create multiple blocks.
+
+## Requirements
+
+* `ps`
+* `top`
+
+## Syntax
+
+```txt
+______________________________________________________________________
+
+CHECK_REQUIREMENTS
+v1.2
+
+(c) Institute for Medical Education - University of Bern
+Licence: GNU GPL 3
+
+https://os-docs.iml.unibe.ch/icinga-checks/Checks/check_requirements.html
+______________________________________________________________________
+
+Check if a list requirements regarding processes and network 
+connections do exist.
+
+The check returns OK if all given requirements match.
+
+SYNTAX:
+check_requirements [-h] [-v] [PARAMETERS]
+
+OPTIONS:
+
+    -h|--help            show this help.
+    -v|--verbose         show more data: processes and port numbers from
+                         /etc/services; add it as first param
+
+PARAMETERS:
+
+    -c|--connect TYPE TARGET PORT        
+                         check if connect to a server to a given port
+                         is reachable
+                         TYPE    string  one of tcp|udp
+                         TARGET  string  target host
+                         PORT    int     port number
+    -l|--label STRING    add label to divide the output in multiple sections
+    -p|--process STRING  check if a process with given regex exists in the
+                         output of 'ps aux'
+    -t|--tcp PORT        check if connect on local tcp port is reachable;
+                         This is a shortcut for '-c tcp localhost PORT'
+
+The parameters can be repeated multiple times. Checks will be executed in
+the given order.
+
+EXAMPLES
+
+check_requirements -p httpd -p mysqld -t 22 -t 80 -t 443 -t 3306
+     Check if
+     - a process httpd and a process mysqld exist
+     - localhost listens to ports 22, 80, 443 and 3306
+
+check_requirements -l "webservice" -p httpd -t 80 -t 443 -l "database" -p mysqld -t 3306
+     Use output with multiple sections
+
+```
+
+### Parameters
+
+(none)
+
+## Examples
+
+Check a webservice as process and 2 ports: ``check_requirements  -p nginx -t 443 -t 80``
+
+```txt
+OK: 3 Requirement checks - errors: 0
+
+STATUS  TYPE        RESULT
+OK      process     nginx (2 x)
+OK      connection  tcp to localhost on port 443
+OK      connection  tcp to localhost on port 80
+```