DL3030

Use the -y switch to avoid manual input yum install -y <package>

Problematic code:

FROM centos
RUN yum install httpd-2.24.4 && yum clean all

Correct code:

FROM centos
RUN yum install -y httpd-2.24.4 && yum clean all

Rationale:

Without the -y flag or the equivalent --assumeyes flag, yum will not successfully install a package, because human input is expected. The -y flag makes yum assume 'yes' as the answer to prompts during the installation.