4.2.1 Install Python across Exadata compute nodes using DCLI

Instructions for installing Python across Exadata compute nodes using DCLI.

These steps describe building and installing Python for Exdata.

1. Go to the Python website and download the Python 3.9.5 XZ compressed source tarball and untar it. The downloaded file name is Python-3.9.5.tar.xz

   wget https://www.python.org/ftp/python/3.9.5/Python-3.9.5.tar.xz
   tar xvf Python-3.9.5.tar.xz

2. OML4Py requires the presence of the perl-Env libffi-devel, openssl, openssl-devel, tk-devel, xz-devel, zlib-devel, bzip2-devel, readline-devel and libuuid-devel libraries. Install these libraries using the command:

   dcli -t -g nodes -l root "yum -y install perl-Env libffi-devel openssl openssl-devel tk-devel xz-devel zlib-devel bzip2-devel readline-devel libuuid-devel"
   

3. Set the PYTHONHOME environment on each node:

   dcli -t -g nodes -l oracle "export PYTHONHOME=$ORACLE_HOME/python; export PATH=$ORACLE_HOME/python/bin$PATH; export LD_LIBRARY_PATH=$ORACLE_HOME/python/lib:$LD_LIBRARY_PATH; export PIP_REQUIRE_VIRTUALENV=false"
   dcli -t -g nodes -l oracle "tar xvfz $ORACLE_HOME/Python-3.9.5.tar.xz -C $ORACLE_HOME/python"
   dcli -t -g nodes -l oracle "cd $ORACLE_HOME/python; ./configure --enable-shared --prefix=$ORACLE_HOME/python"
   dcli -t -g nodes -l oracle "cd $ORACLE_HOME/python; make clean; make"
   dcli -t -g nodes -l oracle "cd $ORACLE_HOME/python; make altinstall"

4. Create a symbolic link in your $PYTHONHOME/bin directory. You need to link it to your python3.9 executable, which you can do with the following commands:

   dcli -t -g nodes -l oracle "cd $PYTHONHOME/bin"
   dcli -t -g nodes -l oracle "ln -s python3.9 python3"

5. Set environment variable PYTHONHOME and add it to your PATH, and set environment variable LD_LIBRARY_PATH:

   dcli -t -g nodes -l oracle "export PYTHONHOME=$ORACLE_HOME/python"
   dcli -t -g nodes -l oracle "export PATH=$PYTHONHOME/bin:$PATH"
   dcli -t -g nodes -l oracle "export LD_LIBRARY_PATH=$PYTHONHOME/lib:$LD_LIBRARY_PATH"
   dcli -t -g nodes -l oracle "export PIP_REQUIRE_VIRTUALENV=false"

6. You can now start Python by running the command python3. For example:

   dcli -t -g nodes -l oracle "python3"

   exadb01: Python 3.9.5 (default, Feb 10 2022, 14:38:12)         
       [GCC 4.8.5 20150623 (Red Hat 4.8.5-44.0.3)] on linux             
       Type "help", "copyright", "credits" or "license" for more information.
   
   exadb02: Python 3.9.5 (default, Feb 10 2022, 14:38:12)         
       [GCC 4.8.5 20150623 (Red Hat 4.8.5-44.0.3)] on linux  
       Type "help", "copyright", "credits" or "license" for more information.