ERT - Ensemble based Reservoir Tool - is designed for running ensembles of dynamical models such as reservoir models, in order to do sensitivity analysis and data assimilation. ERT supports data assimilation using the Ensemble Smoother (ES), Ensemble Smoother with Multiple Data Assimilation (ES-MDA) and Iterative Ensemble Smoother (IES).
The pattern for detecting error messages from the Eclipse output
https://github.com/equinor/ert/blob/cc33a48341d019c88b1b5e414e99b85317f762ca/src/ert/resources/forward_models/res/script/ecl_run.py#L50
will not catch errors when Eclipse uses multiple CPUs which can look like this: