uima-ducc-duccdocs/src/site/tex/duccbook/part4/sm.tex

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\chapter{Service Management}
\label{chap:sm}
    The only administrative task relating to Service Management is registering
    global pingers, as described in
    \hyperref[subsec:services.pingers]{\em Service Pingers section} of this document.

    A globally-registered service pinger is a properties file that contains only
    service registraton options pertaining to pingers.  This file must be placed
    in DUCC's {\em runtime}/resources/service\_monitors directory.  It may be
    given any name but ``best practices'' would suggest it be named the
    same as the {\em service\_ping\_class}.  Services then use this pinger
    by specifying its filename in their {\em service\_ping\_class} option.
    
    Globally-registered pingers may be run internally as threads within the
    SM, or externally as processes.  To specify that a pinger be run internally,
    add the property 
\begin{verbatim}
    internal = true
\end{verbatim}
    to the registration file.  To specify that it run externall, add the property
\begin{verbatim}
    internal = false
\end{verbatim}
    to the registration file.

    The ``internal'' option is flagged as in illegal option when
    specified in service registrations and all pingers not specified as
    ``internal'' are run as {\em external} processes managed by the SM.

    Best practices dictate that the filename of an {\em external} pinger contain the
    postfix {\em .external} to clearly identify it as external.  

    As an example, the default UIMA-AS pinger is supplied in the global registery
    under the two names:
\begin{verbatim}
    org.apache.uima.ducc.cli.UimaAsPing
    org.apache.uima.ducc.cli.UimaAsPing.external
\end{verbatim}

    Note that users may override any of the properties in globally-registered
    {\em external} pingers, but only the {\em service\_ping\_arguments} of an {\em internal}
    pinger to protect its integrity by speicfy that argument in their own
    service registrations.

    By default external pingers are launched with the same JRE as used by the DUCC daemons but if the
    registration contains a entry for the JAVA\_HOME environment variable, that JRE will be used instead.