6. Interpret Contents of a Dockerfile 200-901 Practice Questions (Page 4)

Questions 16–20

1. 16expert · hard

   A developer is optimizing a Dockerfile for a Python application. The build currently copies the entire source code, installs dependencies, and then runs tests. The developer wants to reduce the number of layers and improve cache efficiency. Which change is most effective?

   • ACombine all `RUN` commands into a single `RUN` command
   • BCopy only the requirements file first, install dependencies, then copy the rest of the source code
   • CUse `ADD` instead of `COPY` for all file copies
   • DUse `ENV` to set all configuration values
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2. 17foundation · easy

   Which Dockerfile instruction would you use to declare a volume at /var/lib/mysql?

   • AVOLUME /var/lib/mysql
   • BENV /var/lib/mysql
   • CMOUNT /var/lib/mysql
   • DEXPOSE /var/lib/mysql
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4. 18foundation · easy

   In a Dockerfile, which instruction is best suited to define the main executable that should always run when the container starts?

   • AENTRYPOINT
   • BEXPOSE
   • CRUN
   • DCMD
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5. 19foundation · easy

   What is the primary difference between CMD and ENTRYPOINT in a Dockerfile?

   • ACMD provides default arguments that can be overridden, while ENTRYPOINT defines the executable that is always run
   • BCMD runs at build time, while ENTRYPOINT runs at container start
   • CENTRYPOINT can be overridden by command-line arguments, while CMD cannot
   • DCMD is used for multi-stage builds, while ENTRYPOINT is used for single-stage builds
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6. 20foundation · easy

   What is a key difference between the ADD and COPY instructions in a Dockerfile?

   • AADD can automatically extract local tar files and fetch remote URLs
   • BCOPY can automatically extract local tar files
   • CADD only copies files from the build context
   • DCOPY can fetch files from remote URLs
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