Interview Q&A / Docker & Kubernetes
Docker & Kubernetes interview questions
Images, containers, Dockerfiles, pods and deployments, from first principles.
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- Why should you never put passwords or API keys in a Dockerfile or image?
Anything baked into a layer, through ENV, ARG, COPY or RUN, can be read by anyone who can pull the image, using docker history or by unpacking layers. Inject secrets at runtime instead.
BeginnerQuick answer1 min read - Why should you pin the base image version in a Dockerfile?
FROM python without a version or with latest can change between builds, so a rebuild may break or introduce new vulnerabilities. Pinning a specific tag or digest gives repeatable builds you update on purpose.
BeginnerQuick answer1 min read - Why use WORKDIR instead of RUN cd in a Dockerfile?
WORKDIR sets the working directory for all later instructions and the running container, and creates it if missing. RUN cd only affects that single RUN line, because each RUN starts a fresh shell.
BeginnerQuick answer1 min read