DC/OS E2E includes Dockerfiles - one for each supported OS.
Each of these includes dependencies.
Some of these are "real" DC/OS documented dependencies.
Some of these are not.
For example, including bind-utils in the CentOS Dockerfile meant that we did not catch DCOS-40140 in CI, because that package includes dig, that is not a named requirement of DC/OS.
We should carefully remove all non-required dependencies in those Dockerfiles.