# pmdasimple

## NAME



           **pmdasimple** - simple performance metrics domain agent (PMDA)
    


## SYNOPSIS



           **$PCP_PMDAS_DIR/simple/pmdasimple**[**-D** _debug_] [**-d** _domain_] [**-i** _port_]
           [**-l** _logfile_] [**-p**] [**-U** _username_] [**-u** _socket_]
    


## DESCRIPTION



           **pmdasimple** is a simple Performance Metrics Domain Agent (PMDA)
           which exports a small number of synthetic performance metrics.
    
           The simple PMDA is shipped as source code and is designed to be an
           aid for PMDA developers.  In terms of code size and features, it
           is more complex than the trivial PMDA, about the same as the txmon
           PMDA and less complex than the sample PMDA.  The source for the
           simple PMDA is a good template from which production, customized
           PMDAs can be developed.
    
           A brief description of the **pmdasimple** 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.
    
           **-i** Expect PMCD to connect to **pmdasimple** on the specified TCP/IP
                port.  _port_ may be a port number or port name.
    
           **-l** Location of the log file.  By default, a log file named
                _simple.log_ is written in the current directory of pmcd(1)
                when **pmdasimple** 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.
    
           **-p** Expect PMCD to create a pipe and the connection to **pmdasimple**
                is via standard input and standard output.  This is the
                default connection mode.
    
           **-u** Expect PMCD to connect to **pmdasimple** on the Unix domain
                socket named _socket_.
    
           **-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.
    
           At most one of the options **-i** , **-p** and **-u** may be specified.
    


## INSTALLATION



           If you want access the names, help text and values for the simple
           performance metrics, do the following as root:
    
                # cd $PCP_PMDAS_DIR/simple
                # ./Install
    
           If you want to undo the installation, do the following as root:
    
                # cd $PCP_PMDAS_DIR/simple
                # ./Remove
    
           **pmdasimple** 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



           **$PCP_PMCDCONF_PATH**
                  command line options used to launch **pmdasimple**
           **$PCP_PMDAS_DIR/simple/help**
                  default help text file for the simple metrics
           **$PCP_PMDAS_DIR/simple/Install**
                  installation script for the **pmdasimple** agent
           **$PCP_PMDAS_DIR/simple/Remove**
                  undo installation script for the **pmdasimple** agent
           **$PCP_PMDAS_DIR/simple/simple.conf**
                  configuration file for the dynamic instance domain that
                  underlies the **simple.now** performance metric.  For a
                  description, refer to the help text file, or run the
                  command
                  $ pminfo -T simple.now
           **$PCP_PMDAS_DIR/simple/*.pmda_simple.so**
                  The DSO version of the PMDA.  The same source is used to
                  create both the DSO and the daemon versions of the simple
                  PMDA, and one or the other may be installed as part of the
                  dialog in the **Install** script.
           **$PCP_LOG_DIR/pmcd/simple.log**
                  default log file for error messages and other information
                  from **pmdasimple**
    


## 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.
    


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