> Small project, happily using generic VM. Everybody tell me I should use Docker. Where is the catch? The catch is that you have a working system you are happy

> Small project, happily using generic VM. Everybody tell me I should use Docker. Where is the catch? The catch is that you have a working system you are happy with, whereas using Docker introduces a learning curve (a time sink) and a configuration/testing cycle (at the least) that will not benefit you at all in your current use case. I say that authoritatively, as if it were not the case then you wouldn't be 'happily using generic VM' and would, instead, be asking about whether Docker would solve your ongoing issue. --- On a more expansive and general note about Docker, it has its place. I've done Docker, but I've also done stuff ranging from the simple Git push-to-deploy, through third parties like Buddy/Codeship/Azure, cloud containers like AWS Fargate (with Docker), VMs with Terraform and Packer, and more. All have their sweet spots, but your question is specifically about Docker. - If you have low/zero code dependencies or can deploy pre-built binaries (eg Go, Net Core) then you probably don't care about the OS beyond choosing an LTS version you can redeploy to at will. For that situation you don't need Docker; just blue/green onto existing or new images. - If you use interpreted/scripted languages (eg Python, Ruby), or you build binaries in-situ (eg Go, Net Core), then you probably need full control over your OS configuration and installed tooling. For that situation you have options, including Docker. All of that is overridden by considering the same question, but about dependencies in relation to your scaling methodology. If it supports scaling with standard images you may not need Docker. If it needs specific configurations then Docker is a good choice. And finally, if you plan on using larger deployment tools or cloud provisioning then there may be non-Docker options to choose from - but at that kind of scale introducing Docker is probably the easiest way forward as it is acceptable to pretty much all related tooling.