Docker
Docker is an enterprise container platform.[1] A container is a unit of sotfware that packages all dependencies together, while still using the underlying server's kernel (base system).[2]
Docker was originally written to address the issue of enterprise software. It gave a way to bundle services that needed to run concurrently but may have had different dependencies. E.g. the web server may require Perl version 5.30, but the database server may require Perl version 5.26, and the web server needed to communicate with the database server both running on the same physical computer. Docker provides a way to bundle the web server software with all its dependencies into a separate "container" from the database server software with all of its own separate dependencies.
Use of Docker has expanded beyond its initial scope. In most cases, it works very well because the users are single users on single-user systems: someone wants to run a complex software bundle on the lab workstation, for example.
Docker requires "root" access in order to work. Root access grants full control over the server: the ability to read, write, modify, delete any data, the ability to reconfigure hardware, and the ability to completely wipe all storage clean unrecoverably. As such, it is not well-suited for a shared cluster computing system such as Proteus or Picotte. It also has no support for the high performance networking hardware used in HPC clusters.
Additionally, the version of Red Hat that runs on Proteus does not support Docker.
If you require containers, use Singularity instead. Singularity can run Docker images.
References
[1] Docker webpage