Python server

ptpython

  • We install ptpython, a prompt-toolkit Python interactive interpreter frontend which gives you omni-completion.

  • In scripts, use /usr/bin/python3 but try ptpython instead of python3 when running individual commands manually.

python-is-python3

  • Debian uses /usr/bin/python3 as the Python 3 interpreter. Some other distributions use /usr/bin/python for Python 3.

  • If you want to have /usr/bin/python additionally pointing to the Python 3 interpreter, you can install the python-is-python3 package.

Installing software

We update all systems automatically, however, you can update it manually with:

sudo apt full-upgrade -U

Software from the Debian repository can be installed with:

sudo apt install -U [...]

i.e. sudo apt install -U tmux.

Software not included in the Debian repository needs to be manually installed in your home. Depending on the build system of the software, consider using DESTDIR=$HOME/local or similar.

Scratch space

/mnt/local/scratch gives you access to local scratch space, i.e. temporary storage on the hosts fast SSDs.

Please note:

  • no backup: if you delete something by accident, data is gone.

  • no persistency: if we move the container to another host server, all data is gone.

  • limited capacity: compared to Ceph with hundrets of TB of space, the host servers just have two local SSDs in RAID1 shared with all containers for scratch space.

  • no guarantees: if required, we reserve the right to delete data if necessary even without prior notice in order to ensure stable and secure operation.

  • rule of thumb: only store temporary data which you would asume would be gone after a reboot (/tmp).

  • best practice: use /mnt/local/scratch (fast local SSDs) instead of /tmp (RAM disk). /tmp will either eventually kill your processes when used excessively or slow down your calculations because of wasted RAM.