CKAD Application Design and Build Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  EXPOSE

  Why it's wrong here

  EXPOSE is a metadata instruction that documents which ports the container listens on, but it has no effect on the filesystem or the process's current working directory. It is used for image documentation and to inform Docker desktop or orchestration tools about expected network ports. Therefore, it cannot set the working directory for subsequent build instructions or the runtime process.

• ✓

  WORKDIR

  Why this is correct

  WORKDIR sets the working directory for all subsequent Dockerfile instructions, including RUN, CMD, ENTRYPOINT, COPY, and ADD. It automatically creates the directory if it does not exist, and it can be used multiple times to change the directory for later steps. At runtime, this becomes the initial working directory of the container process, so any relative paths or shell commands execute from that location.

• ✗

  COPY

  Why it's wrong here

  COPY is a build instruction that copies files or directories from the build context (host) into the image filesystem at a specified destination path. While the destination path may place files into a particular directory, COPY does not alter the default working directory that subsequent instructions or the container process will use. The working directory remains whatever was set by the last WORKDIR, or the root if none was set.

• ✗

  USER

  Why it's wrong here

  USER sets the username or UID that will be used to run any subsequent RUN instructions as well as the default user for the container process at runtime. This instruction affects security and permission context, but it is completely unrelated to filesystem paths and does not change the current directory. Thus, USER cannot be used to set the working directory.