Teaching robotics with the robot operating system (ROS) is valuable for instating good programming practices but requires significant setup steps from the learner. Providing a ready-made ROS learning environment over the web can make robotics more accessible; however, most of the previous remote labs have abstracted the authentic ROS developer environment either for didactical or technological reasons, or do not give the possibility to program physical robots. In this article, we present a remote web lab that employs virtual network computing and Docker to serve in-browser desktop workstations, where learning tasks can be completed on both the physical and simulated robots. The learners can reserve access to the remote lab through a learning management interface, which also includes tools for administering the remote lab. The system allows anyone to experiment with ROS without configuring any software locally and was successfully trialed in an online ROS course.