The existing Dockerfiles are non-operational as they are due to the mirrorlist host being taken offline:
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=container error was
0.900 14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
For anyone reading this, https://vault.centos.org/ is apparently an alternative to the mirror that has been disabled. We're not planning on using it, but FYI.
Deleting these Dockerfiles due to CentOS 7 EOL.
The existing Dockerfiles are non-operational as they are due to the mirrorlist host being taken offline: