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I disagree with the premise that using Docker to run individual processes is "wrong". Phusion is doing a disservice by suggesting as such. There ARE use-cases w

I disagree with the premise that using Docker to run individual processes is "wrong". Phusion is doing a disservice by suggesting as such. There ARE use-cases where such a base-image is useful, but I believe these should be the uncommon case, not the common one. Even yet, if running multiple processes in a container is needed, it's preferable to use Docker-in-Docker. I suppose part of the problem is the two benefits of Docker and containerization are frequently confused. Docker provides portability and build bundling, but ALSO provide loose process isolation. You should want to take advantage of that process isolation and by doing so, should want to run SSH or cron in their own containers, not in a single container with your application process. If your application has multiple processes, each should have their own containers. These containers can be linked and share volumes, devices, namespaces, etc. Granted, some of the functionality one might desire for this model is still missing or in development, but much of it is there already and that's the model I aspire Docker to follow. It might also be to some degree a matter of legacy versus green-field applications. For instance, I've been deploying OpenStack's 'devstack' developer environment (which forks dozens of binaries) inside of a single Docker container. In this case, the Phusion base-image might make sense. However, the proper way of using Docker would be to run dozens of containers, each running a single service. The reason I don't do this is because the OpenStack development/testing tools provide this forking and enforce this model, using 'screen' as a pseudo-init process. From the Docker perspective, this is a legacy application. I could and probably will change those development tools to create multiple containers, but until then, it's easiest to stick to a single container.

bashcoder 13y ago
Yeah, Phusion oversells their case when they say this is the "right way" to do it. It's one way to do it, and this methodology probably addresses customer support issues they are having. Many of their customers likely misunderstand what's actually going in a container by default. I'd rather see a more balanced approach that shows a range of options, without opining so much about how Docker containers should or should not be used. Better to fit the solution to a particular use case.
tinco 13y ago
I disagree with the premise that using Docker to run individual processes is "wrong". Phusion is doing a disservice by suggesting as such. This is not the premise of the article. The premise is that someone goes 'from ubuntu; apt-get install memcache; cmd ["memcached"]' and thinks everything is going to be alright, when in reality they've just set up a rather buggy system. If you're absolutely certain your app is going to be fine running as the sole (PID1) process in the container, then this article has no problem with that. It just says that if you're going to run something you've got from apt-get, then chances are, your system is going to have to be a little more like a Debian system.

bashcoder 13y ago

Yeah, Phusion oversells their case when they say this is the "right way" to do it. It's one way to do it, and this methodology probably addresses customer support issues they are having. Many of their customers likely misunderstand what's actually going in a container by default. I'd rather see a more balanced approach that shows a range of options, without opining so much about how Docker containers should or should not be used. Better to fit the solution to a particular use case.

tinco 13y ago

I disagree with the premise that using Docker to run individual processes is "wrong". Phusion is doing a disservice by suggesting as such. This is not the premise of the article. The premise is that someone goes 'from ubuntu; apt-get install memcache; cmd ["memcached"]' and thinks everything is going to be alright, when in reality they've just set up a rather buggy system. If you're absolutely certain your app is going to be fine running as the sole (PID1) process in the container, then this article has no problem with that. It just says that if you're going to run something you've got from apt-get, then chances are, your system is going to have to be a little more like a Debian system.