Solver Configuration
At OET, we use both open source and proprietary solvers. Proprietary solvers require a license. Users must configure the details of the solver license before using them.
Configuring Gurobi
Our gurobi license is limited to 5 users in parallel. If a project is running multiple solves in parallel, we can run out of available licenses. As OET expands, license contention will become an increasing problem.
There are multiple ways to configure Gurobi. We do not recommend the standard approach as it increases license contention. Instead, use the preferred approach.
Standard Approach
Rename and copy the gurobi.lic file in your /home folder. Get solving...
Preferred Approach
To mitigate license contention, linopy releases from v0.5.6 now support passing in solver license details as environment variables.
In practice, these can be included as part of your PyPSA configuration file by editing the config/config.yaml file (which is not tracked in version control)
to include:
solving:
solver_options:
gurobi-default:
env:
WLSACCESSID: "..."
WLSSECRET: "..."
LICENSEID: ...
Make sure that LICENSEID is not quoted and reads like a plain integer.
Use this instead of adding the gurobi.lic to your home folder. This approach only uses the license during the actual solving step,
rather than locking a license for the duration of the workflow runtime.
FAQ
Q. What if I already have a gurobi.lic file in my home folder? Will the environment variable entries take precedence?
A. No, you must remove the Gurobi license file from your home folder.
Q. How do I prevent license secrets from being included in a Pull Request?
A. The config/config.yaml file is not tracked - it is ignored by git. This PR adds gitleaks to the pre-commit,
and warns of any secrets about to be added to the git history.