HttpMonitor utilizes the HTTP protocol to test the connection and timing between a webserver (Device) and client (HttpMonitor).

The following list items explain the various fields in the httpmonitor datasource

• Name
  • Arbitrary title given to data source
• Source Type
  • This is not an option. In our case, it is the HttpMonitor Type. This field defines what category of data is being worked on. You may see others like “SNMP”, or “DNSMonitor”
• Enabled
  • You can use this to turn on/off this data source. This may be useful if you want to turn off the functionality of the data source, but don’t want to delete it. This makes for an easy process to turn the data source back on, in the future.
• Component
  • Events that happen will get this component (like eth0, httpd, etc)
• Event Class
  • Which Event Class any events will belong to, if they happen. Different from Device Classes
• Event Key
  • If a component needs further deduplication specification this field may be used. Deduplication is when an event is determined if it is the same as another event, and therefore classified as the same or separate event.
• Severity
  • Original severity of events that this source cause
• Timeout (seconds)
  • Amount of time that can go by, before the transaction is labeled as not happening (timed out)
• Cycle Time (seconds)
  • Time between re-runs of HttpMonitor, defaults to 300 seconds
• Host Name
  • This is the domain of the website that you want to check. Enter a Fully Qualified Domain Name (FQDN), ex: host.zenoss.com; This field defaults to ${dev/id}, which references the current devices ID. If you reference the current devices ID, and it is not a domain name, HttpMonitor will not work properly.
• IP Address
  • IP to use if needed, eg: 124.12.56.123; defaults to use zope object ${dev/manageIp}, which references the current devices IP address
• Port
  • If you have web server running on non-standard port (ex: Zenoss runs 8080 by default)
• Use SSL
  • HTTPS for secure, encrypted webpages
• Url
  • Usually the directory and file names after the host name
  • Ex: You have already defined http://host.zenoss.com above
    • inserting a / is just the root
    • inserting /vm1/insert.php will interpret as http://host.zenoss.com/vm1/insert.php
• Regular Expression
  • Uses PCRE regular expression syntax to find the regex on the page loaded
  • If not found, throws error of level ‘Severity’ set above
  • See http://nickyeates.com/technology/zenoss/about/regex
• Case Sensitive
  • Does regex care about upper and lower case when searching for string?
• Invert Expression
  • Negates Regex logic.
  • If regex found, throws error
• Basic Auth User
  • If webpage requires basic login authentication
• Basic Auth Password
  • See above
• Redirect Behavior
  • If page visited, trys to redirect, what is done?

$ZENHOME/libexec/check_http --help
check_http (nagios-plugins 1.4.5) 1.96
Copyright (c) 1999 Ethan Galstad <nagios@nagios.org>
Copyright (c) 1999-2006 Nagios Plugin Development Team
        <nagiosplug-devel@lists.sourceforge.net>

This plugin tests the HTTP service on the specified host. It can test
normal (http) and secure (https) servers, follow redirects, search for
strings and regular expressions, check connection times, and report on
certificate expiration times.


Usage: check_http -H <vhost> | -I <IP-address> [-u <uri>] [-p <port>]
       [-w <warn time>] [-c <critical time>] [-t <timeout>] [-L]
       [-a auth] [-f <ok | warn | critcal | follow>] [-e <expect>]
       [-s string] [-l] [-r <regex> | -R <case-insensitive regex>] [-P string]
       [-m <min_pg_size>:<max_pg_size>] [-4|-6] [-N] [-M <age>] [-A string] [-k string]
NOTE: One or both of -H and -I must be specified

Options:
 -h, --help
    Print detailed help screen
 -V, --version
    Print version information
 -H, --hostname=ADDRESS
    Host name argument for servers using host headers (virtual host)
    Append a port to include it in the header (eg: example.com:5000)
 -I, --IP-address=ADDRESS
    IP address or name (use numeric address if possible to bypass DNS lookup).
 -p, --port=INTEGER
 Port number (default: 80)
 -4, --use-ipv4
    Use IPv4 connection
 -6, --use-ipv6
    Use IPv6 connection
 -S, --ssl
   Connect via SSL
 -C, --certificate=INTEGER
   Minimum number of days a certificate has to be valid.
   (when this option is used the url is not checked.)

 -e, --expect=STRING
    String to expect in first (status) line of server response (default: 
HTTP/1.
    If specified skips all other status line logic (ex: 3xx, 4xx, 5xx processing)
 -s, --string=STRING
    String to expect in the content
 -u, --url=PATH
    URL to GET or POST (default: /)
 URL to GET or POST (default: /)
,-P, --post=STRING    URL encoded http POST data
 -N, --no-body
    Don't wait for document body: stop reading after headers.
    (Note that this still does an HTTP GET or POST, not a HEAD.)
 -M, --max-age=SECONDS
    Warn if document is more than SECONDS old. the number can also be of
    the form "10m" for minutes, "10h" for hours, or "10d" for days.
 -T, --content-type=STRING
    specify Content-Type header media type when POSTing

 -l, --linespan
    Allow regex to span newlines (must precede -r or -R)
 -r, --regex, --ereg=STRING
    Search page for regex STRING
 -R, --eregi=STRING
    Search page for case-insensitive regex STRING
 --invert-regex
    Return CRITICAL if found, OK if not

 -a, --authorization=AUTH_PAIR
    Username:password on sites with basic authentication
 -A, --useragent=STRING
    String to be sent in http header as "User Agent"
 -k, --header=STRING
     Any other tags to be sent in http header. Use multiple times for additional headers
 -L, --link=URL
    Wrap output in HTML link (obsoleted by urlize)
 -f, --onredirect=<ok|warning|critical|follow>
    How to handle redirected pages
 -m, --pagesize=INTEGER<:INTEGER>
    Minimum page size required (bytes) : Maximum page size required (bytes)
 -w, --warning=DOUBLE
    Response time to result in warning status (seconds)
 -c, --critical=DOUBLE
    Response time to result in critical status (seconds)
 -t, --timeout=INTEGER
    Seconds before connection times out (default: 10)
 -v, --verbose
    Show details for command-line debugging (Nagios may truncate output)
Notes: This plugin will attempt to open an HTTP connection with the host.
 Successful connects return STATE_OK, refusals and timeouts return STATE_CRITICAL
 other errors return STATE_UNKNOWN.  Successful connects, but incorrect reponse
 messages from the host result in STATE_WARNING return values.  If you are
 checking a virtual server that uses 'host headers' you must supply the FQDN
 (fully qualified domain name) as the [host_name] argument.
 This plugin can also check whether an SSL enabled web server is able to
 serve content (optionally within a specified time) or whether the X509 
 certificate is still valid for the specified number of days.
Examples: CHECK CONTENT: check_http -w 5 -c 10 --ssl www.verisign.com

 When the 'www.verisign.com' server returns its content within 5 seconds,
 a STATE_OK will be returned. When the server returns its content but exceeds
 the 5-second threshold, a STATE_WARNING will be returned. When an error occurs,
 a STATE_CRITICAL will be returned.

 CHECK CERTIFICATE: check_http www.verisign.com -C 14

 When the certificate of 'www.verisign.com' is valid for more than 14 days,
 a STATE_OK is returned. When the certificate is still valid, but for less than
 14 days, a STATE_WARNING is returned. A STATE_CRITICAL will be returned when
 the certificate is expired.


Send email to nagios-users@lists.sourceforge.net if you have questions
regarding use of this software. To submit patches or suggest improvements,
send email to nagiosplug-devel@lists.sourceforge.net