The "OS" part of a Docker image is really just a minimal environment that "looks and feels" like Ubuntu, CentOS, etc. You're not actually virtualizing a full O

The "OS" part of a Docker image is really just a minimal environment that "looks and feels" like Ubuntu, CentOS, etc. You're not actually virtualizing a full OS. Running a Docker image is essentially equivalent to running a process (whatever process is defined by your image, i.e. Apache, MySQL, etc.).