  A separable, proper morphism of varieties with geometrically connected fibers
induces a homotopy exact sequence relating the \'etale fundamental groups of
source, target and fiber. Extending work of dos Santos, we prove the existence
of an analogous homotopy exact sequence for fundamental group schemes
classifying regular singular stratified bundles, under the additional
assumption that the morphism in question can be (partially) compactified to a
log smooth morphism.
