ERROR ==> Invalid kernel settings. Elasticsearch requires at least: vm.max_map_count = 262144

If the error above pops in Docker for windows or the Docker Toolbox, (happened to me while installing the bitnami docker image for Magento2) what you have to do is change the docker-machine sysctl settings as follows:

docker-machine ssh
sudo sysctl -w vm.max_map_count=262144