Exam 350-901 topic 1 question 151 discussion

B Here’s How: While you can’t directly set ENV variable values when running docker build, you can use ARG to pass through --build-arg values right into your ENV instructions. Source: https://vsupalov.com/docker-build-time-env-values/#:~:text=While%20you%20can't%20directly,right%20into%20your%20ENV%20instructions.&text=You%20can%20change%20the%20value,build%20without%20editing%20the%20Dockerfile.

ARG TOKEN=$BOT_TOKEN ENV WEBEX_TEAMS_ACCESS_TOKEN="$TOKEN" CMD ["python", "bot_app.py"] Explanation: ARG TOKEN=$BOT_TOKEN: This allows the build-time argument BOT_TOKEN to be passed using the docker build --build-arg BOT_TOKEN=$bot_token command. The value of BOT_TOKEN (e.g., the Webex bot token) will be available during the build process. ENV WEBEX_TEAMS_ACCESS_TOKEN="$TOKEN": This sets an environment variable WEBEX_TEAMS_ACCESS_TOKEN in the Docker container, making the token available to the application runtime. CMD ["python", "bot_app.py"]: This specifies the command to run the Python application when the container starts.

None of the answers is correct. The Build Arg is called BOT_TOKEN, and its not consumed in any of the answers. It would need to be: ARG BOT_TOKEN ENV WEBEX...="$BOT_TOKEN"

B is correct: you can have environment variables (ENV) and build arguments (ARG) with different names in a Dockerfile. In fact, it's common practice to use different names to make their purposes clear and to avoid any potential conflicts or confusion

This should be B. D seems valid enough, but when trying to build the container using the given Dockerfile, i got the following error : [Warning] One or more build-args [BOT_TOKEN] were not consumed thus you have to use ARG command to retrieve ARGs However B is incorrect too, since the ARG syntax is : ARG <my arg>=default My guess is that the correct Dockerfile is ARG BOT_TOKEN ENV WEBEX..="$BOT_TOKEN"

I think A and C can be disregarded to the use of the EXPORT statement. Otherwise, both B and D would match the question. Analysing the difference between B and D, ChatGPT has the following view which makes me thing B would be better: To summarize, the key difference is that the first Dockerfile (b) allows for flexibility in passing the value of TOKEN as an argument during the build process, while the second Dockerfile (d) sets the environment variable directly without the ability to override it during the build process.

D. As the build statement references BOT_TOKEN and not TOKEN so the provided answer is correct in my opinion

B looks like the correct approach