This issue arises due to the end of life (EOL) status of CentOS 7, which results in the inability to retrieve its mirrorlist. When building Docker images with CentOS 7, users experience broken builds as repositories are no longer maintained. Solutions include switching to CentOS Stream 8 or using an archived repository from CentOS Vault. Another option is moving to alternatives like AlmaLinux.

A Dockerfile's ability to distinguish between COPY and ADD commands is essential for effective Dockerfile administration. To provide a safe and reliable build environment, copy local files and directories inside a container with the COPY command.

Effective container management requires an understanding of the minor differences between CMD and ENTRYPOINT in Dockerfiles. Despite their apparent similarities, the two commands have different objectives: While ENTRYPOINT guarantees that a command is always run, CMD offers default arguments.