This builds an ubuntu 18.04 container for dev / test
docker build -t frr-ubuntu18:latest -f docker/ubuntu18-ci/Dockerfile .
docker run -d --privileged --name frr-ubuntu18 --mount type=bind,source=/lib/modules,target=/lib/modules frr-ubuntu18:latest
docker exec frr-ubuntu18 bash -c 'cd ~/frr ; make check'
docker exec -it frr-ubuntu18 bash
docker exec frr-ubuntu18 bash -c 'cd ~/frr/tests/topotests/ospf-topo1 ; sudo pytest test_ospf_topo1.py'
docker stop frr-ubuntu18 ; docker rm frr-ubuntu18
docker rmi frr-ubuntu18:latest