General Helpful Tips

[AJVincelli]

Hello, after working with Launcher on 2 different clusters (Slurm and LSF), I learned a few things that might be helpful to others. I'm not sure where to put these, so I'm putting them here:

• The LAUNCHER_JOB_FILE command script (the script with one command per line, such as helloworld_multi_output) MUST have an empty line at the end, or Launcher will not push the last command in the list! For instance, if there are 300 lines of commands in the Launcher script, make sure there are (at least) 301 total lines in the file.
• On some clusters, submitting the job from within a GNU Screen session results in the error "syntax error near unexpected token" or similar. (This is because GNU Screen sets some environmental variables that include special syntax, such as a close parenthesis ")" which is incompatible with some scripts that read those variables.) If you encounter this error, exit the Screen session before submitting the job. Or you can add a few things to the pass_env file as noted in Pull Request Exclude GNU Screen environmental variables in pass_env #66 , this fixed the issue for me.
• On some clusters, the default version of Python is older than 2.7, AND even after loading a newer version of Python as a module it will still use the older version. You can check this by entering "module load python3/3.5.0" or similar, and then entering "python --version" and hopefully it will show the newer version of Python! However, if it still shows the old version of Python even after loading the newer Python module, and you are getting a "Python version 2.7 or better required" error, you can force the use of the newer Python version by replacing the word "python" in line 1 of tskserver with "python3" so that it will use the newer version.

Hopefully these tips help others! If there's a better place to document these, please let me know (or feel free to move them).