Will Docker be a long-term solution, or is there technology on the horizon that will supersede it?
I think It is probably safe to say containerisation and DevOps processes are an established part of software development now, but it will keep evolving and eventually, existing solutions will get superseded. If you look at this moment Kubernetes and Docker are the major implementations so are the ones that most people use, but something will almost certainly come along in time. If you want to learn more about Docker then I would suggest you must take up the following Docker Training Course. I am also mentioning a video tutorial for you which you must watch.