When is it Better to Avoid Using Docker?

One major consideration is performance. If you need to squeeze out every bit of performance, Docker could introduce slight overhead due to the union filesystem, especially during writes. Also, dealing with permission issues can be a hassle at times, so that might be another reason to stick with a direct install if it's causing you more trouble than it’s worth.

I have a VPS with only 768MB of RAM, so every megabyte counts. Running services directly instead of in Docker saved me from the dreaded OOM killer who frequently took down my containers. Performance considerations can definitely influence whether Docker is a good fit.

For smaller setups or when you don't need isolation, it might be simpler to run directly on the machine. If you have poor observability tools or need full access to logs and configs, going raw can be a better fit.

If you have a machine that's dedicated to a single task, like a database server running one process, then using Docker might complicate things unnecessarily. Docker’s overhead is usually minimal but it still exists, and that can add another layer of complexity to debug.

Sometimes, vendor-supplied applications won't support Docker. If you're dependent on certain software that has licensing tied to hardware IDs or MAC addresses, Docker may not be feasible. In those cases, you might want to run it natively.