AlmaLinux 9 on ekumen.nevis.columbia.edu

At present, I've positioned ekumen to act as a testbed for the VERITAS/CTA group as we contemplate a transition to AlmaLinux 9 (a free variant of Redhat Enterprise Linux 9).

Here's what will help you explore the system:

• ekumen is part of the Nevis Linux cluster. If you can login to tehanu, you can login to ekumen.

• Like ged (for example), ekumen is behind the Nevis firewall. To access ekumen, you'll either have to "double-hop" by ssh-ing to tehanu and then to ekumen, or use Nevis VPN.

• Since ekumen is part of the Nevis Linux cluster, your home directory on ekumen is the same as it on any other machine. Probably it's on tehanu. That means that if you use pip3 or conda or other package-management tools, the related files will be stored in your home directory, not on ekumen.

• As noted, the operating system is AlmaLinux 9. There are some substantial differences between AlmaLinux 9 and CentOS 7.

• The environment modules commands (like module load root) won't work on ekumen, because of May-2023 I haven't re-compiled any packages for AlmaLinux 9 yet.

• However, AlmaLinux 9 is not the old-and-creaky operating system that CentOS 7 was. Its native packages may be good enough for your work:
  • Linux kernel 5.14.0
  • gcc 11.3
  • python 3.9
  • root 6.28/02

• I've also installed the following packages as part of the Python libraries on ekumen (note the inclusion of some Python DL libraries): jupyter jupyterlab iminuit numpy scipy matplotlib pandas sympy terminado urllib3 tables rootpy rootkernel uproot scikit-learn tensorflow keras torch torchvision scikit-hep h5py astropy gammapy fitsio healpy astropy-healpix cython numba numba_stats xgboost.

• This means that instead of typing module load root to run ROOT, try just running it.

• Bear in mind that ekumen is a simple two-processor system. It's meant to test your software, not as a full-fledged analysis machine like tehanu.

If you have any questions or suggestions about the new OS or this setup, please let me know.

-- William Seligman - 2023-05-08