# pmdaapache

## NAME



           **pmdaapache** - Apache2 web server performance metrics domain agent
           (PMDA)
    


## SYNOPSIS



           **$PCP_PMDAS_DIR/apache/pmdaapache**[**-D** _debug_] [**-d** _domain_] [**-l**
           _logfile_] [**-U** _username_] [**-S** _server_] [**-P** _port_] [**-L** _location_]
    


## DESCRIPTION



           **pmdaapache** is a Performance Metrics Domain Agent (PMDA) which
           extracts performance metrics describing the state of an Apache web
           server.
    
           The **apache** PMDA exports metrics that measure the request rate,
           cumulative request sizes, uptime and various connection states for
           active clients.
    
           This information is obtained by performing a HTTP request to the
           server status URL, which must be enabled in the _httpd.conf_
           configuration file.
    
                ExtendedStatus on
                <Location /server-status>
                SetHandler server-status
                Order deny,allow
                Deny from all
                Allow from localhost
                </Location>
    
           A brief description of the **pmdaapache** command line options
           follows:
    
           **-d** It is absolutely crucial that the performance metrics _domain_
                number specified here is unique and consistent.  That is,
                _domain_ should be different for every PMDA on the one host,
                and the same _domain_ number should be used for the same PMDA
                on all hosts.
    
           **-l** Location of the log file.  By default, a log file named
                _apache.log_ is written in the current directory of pmcd(1)
                when **pmdaapache** is started, i.e.  **$PCP_LOG_DIR/pmcd .** If the
                log file cannot be created or is not writable, output is
                written to the standard error instead.
    
           **-S** Query the Apache status information from the named _server_
                rather than the local host.
    
           **-P** Query the Apache status information from the given _port_
                rather than the default (80).
    
           **-L** Specify an alternative _location_ for finding the server-status
                page.
    
           **-U** User account under which to run the agent.  The default is
                the unprivileged "pcp" account in current versions of PCP,
                but in older versions the superuser account ("root") was used
                by default.
    


## INSTALLATION



           If you want access to the names, help text and values for the
           apache performance metrics, do the following as root:
    
                # cd $PCP_PMDAS_DIR/apache
                # ./Install
    
           If you want to undo the installation, do the following as root:
    
                # cd $PCP_PMDAS_DIR/apache
                # ./Remove
    
           **pmdaapache** is launched by pmcd(1) and should never be executed
           directly.  The Install and Remove scripts notify pmcd(1) when the
           agent is installed or removed.
    


## FILES



           **$PCP_PMCDCONF_PATH**
                  command line options used to launch **pmdaapache**
           **$PCP_PMDAS_DIR/apache/help**
                  default help text file for the apache metrics
           **$PCP_PMDAS_DIR/apache/Install**
                  installation script for the **pmdaapache** agent
           **$PCP_PMDAS_DIR/apache/Remove**
                  undo installation script for the **pmdaapache** agent
           **$PCP_LOG_DIR/pmcd/apache.log**
                  default log file for error messages and other information
                  from **pmdaapache**
    


## PCP ENVIRONMENT



           Environment variables with the prefix **PCP_** are used to
           parameterize the file and directory names used by PCP.  On each
           installation, the file _/etc/pcp.conf_ contains the local values for
           these variables.  The **$PCP_CONF** variable may be used to specify an
           alternative configuration file, as described in pcp.conf(5).
    


## DEBUGGING OPTIONS



           The **-D** or **--debug** option enables the output of additional
           diagnostics on _stderr_ to help triage problems, although the
           information is sometimes cryptic and primarily intended to provide
           guidance for developers rather end-users.  _debug_ is a comma
           separated list of debugging options; use pmdbg(1) with the **-l**
           option to obtain a list of the available debugging options and
           their meaning.
    
           Debugging options specific to **pmdaapache** are as follows:
           ┌────────┬──────────────────────────────────────────────────┐
           │ **Option** │ **Description** │
           ├────────┼──────────────────────────────────────────────────┤
           │ **appl0** │ trace each refreshData() call                    │
           ├────────┼──────────────────────────────────────────────────┤
           │ **appl1** │ report badness detected in refreshData()         │
           ├────────┼──────────────────────────────────────────────────┤
           │ **appl2** │ dump internal data after each refreshData() call │
           └────────┴──────────────────────────────────────────────────┘
    


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