Adding Python support for Ganglia - gmond on Centos / RHEL

Ganglia

While creating Ganglia RPM packages for my Centos repository I got stuck with a lack of Python support in Ganglia - gmond. I'll try to to explain details of this whole issue.

First of all one could just install ganglia-gmond packages from Epel repo - and that will make the general case. I checked EPEL packages and those contain modpython.so so go for it ;) But I just couldn't go that way as I had to create my own packages.

First of all - let's check the compilation params regarding to Python:

[[email protected] ganglia-gmond-3.6.0]# ./configure --help | grep -i python
  --disable-python        exclude mod_python and support for metric modules written in python
  --with-python=PATH      Specify prefix for python or full path to interpreter

So by default there should be Python support builtin. But after compiling & building there's no modpython.so library on /usr/lib64/ganglia and that is weird. Digging deeper in config.log there's:

configure:11482: checking for python
configure:11500: found /usr/bin/python
configure:11512: result: /usr/bin/python
configure:11528: checking Python version
configure:11532: result: 2.6
configure:11554: checking Python support
configure:11556: result: no

Hmm - that's really weird. Let's go even more deeper - now with configure.ac:

AC_ARG_WITH( python,
[  --with-python=PATH      Specify prefix for python or full path to interpreter],
[if test x"$withval" != xno; then enable_python="yes"; PYTHON_BIN="$withval"; fi])

[...]

AC_ARG_ENABLE( python,
[  --disable-python        exclude mod_python and support for metric modules written
 in python],
[ if test x"$enableval" != xyes; then enable_python="no"; fi ], [ enable_python="yes" ] )

Ok so it's true - by default there should be Python support. Let's check further (still configure.ac):

if test x"$enable_python" = xyes; then
  echo
  echo Checking for python

  # check for Python executable
  if test -z "$PYTHON_BIN"; then
    AC_PATH_PROG(PYTHON_BIN, python)
  else
    if test -d "$PYTHON_BIN"; then
      PYTHON_BIN="$PYTHON_BIN/bin/python"
    fi
  fi

  if test -n "$PYTHON_BIN"; then
    # find out python version
    AC_MSG_CHECKING(Python version)
    PyVERSION=`$PYTHON_BIN -c ['import sys; print sys.version[:3]'`]
    PyMAJVERSION=`$PYTHON_BIN -c ['import sys; print sys.version[:1]'`]
    AC_MSG_RESULT($PyVERSION)
    PYTHON_VERSION=$PyVERSION
    AC_SUBST(PYTHON_VERSION)

    PyEXEC_INSTALLDIR=`$PYTHON_BIN -c "import sys; print sys.exec_prefix"`
    if test -f "$PyEXEC_INSTALLDIR/include/python/Python.h"; then
      PYTHON_INCLUDES="-I$PyEXEC_INSTALLDIR/include/python"
    else
      if test -f "$PyEXEC_INSTALLDIR/include/python$PyVERSION/Python.h"; then
        PYTHON_INCLUDES="-I$PyEXEC_INSTALLDIR/include/python$PyVERSION"
      else
        PYTHON_INCLUDES=""
        enable_python="no"
      fi
    fi
    AC_SUBST(PYTHON_INCLUDES)
  else
    enable_python="no"
  fi
fi

Ah crap - and here it is. Python support will be disabled and modpython.so library won't be created when there's no header files for Python on our OS. You can make sure if there is Python.h by using locate / find / whatever.

Solution? Just:

yum install python-devel

And that will make it.

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