Containers · Docker interview questions

27 real Containers · Docker questions from the MLOps & Integration bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.

1. What is Image?

Junior
  1. A.a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
  2. B.a bind mount maps a host path into the container; a volume is Docker-managed storage that survives container removal
  3. C.a runnable instance of an image with its own writable layer, network and process space
  4. D.a service such as Docker Hub or ECR that stores and distributes container images
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3. Which statement is correct?

Junior
  1. A.Image — reuse of unchanged image layers across builds so only changed instructions rebuild
  2. B.Image — a runnable instance of an image with its own writable layer, network and process space
  3. C.Image — a bind mount maps a host path into the container; a volume is Docker-managed storage that survives container removal
  4. D.Image — a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
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4. What is Container?

Junior
  1. A.a minimal base image with no shell or package manager, shrinking attack surface for production
  2. B.reuse of unchanged image layers across builds so only changed instructions rebuild
  3. C.a runnable instance of an image with its own writable layer, network and process space
  4. D.a service such as Docker Hub or ECR that stores and distributes container images
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6. Which statement is correct?

Junior
  1. A.Container — reuse of unchanged image layers across builds so only changed instructions rebuild
  2. B.Container — a service such as Docker Hub or ECR that stores and distributes container images
  3. C.Container — a runnable instance of an image with its own writable layer, network and process space
  4. D.Container — a Dockerfile pattern using multiple FROM stages to keep build tools out of the final slim image
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7. What is Dockerfile?

Junior
  1. A.a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
  2. B.a minimal base image with no shell or package manager, shrinking attack surface for production
  3. C.the Open Container Initiative standard format that lets images run across Docker, containerd and CRI-O
  4. D.a text file of instructions (FROM, RUN, COPY, CMD) that defines how an image is built
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9. Which statement is correct?

Junior
  1. A.Dockerfile — a minimal base image with no shell or package manager, shrinking attack surface for production
  2. B.Dockerfile — a text file of instructions (FROM, RUN, COPY, CMD) that defines how an image is built
  3. C.Dockerfile — a runnable instance of an image with its own writable layer, network and process space
  4. D.Dockerfile — a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
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10. What is Registry?

Junior
  1. A.a service such as Docker Hub or ECR that stores and distributes container images
  2. B.a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
  3. C.the Open Container Initiative standard format that lets images run across Docker, containerd and CRI-O
  4. D.a minimal base image with no shell or package manager, shrinking attack surface for production
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12. Which statement is correct?

Junior
  1. A.Registry — a runnable instance of an image with its own writable layer, network and process space
  2. B.Registry — a service such as Docker Hub or ECR that stores and distributes container images
  3. C.Registry — reuse of unchanged image layers across builds so only changed instructions rebuild
  4. D.Registry — a text file of instructions (FROM, RUN, COPY, CMD) that defines how an image is built
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13. What is Layer caching?

Mid
  1. A.a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
  2. B.a text file of instructions (FROM, RUN, COPY, CMD) that defines how an image is built
  3. C.a minimal base image with no shell or package manager, shrinking attack surface for production
  4. D.reuse of unchanged image layers across builds so only changed instructions rebuild
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15. Which statement is correct?

Mid
  1. A.Layer caching — the Open Container Initiative standard format that lets images run across Docker, containerd and CRI-O
  2. B.Layer caching — a bind mount maps a host path into the container; a volume is Docker-managed storage that survives container removal
  3. C.Layer caching — reuse of unchanged image layers across builds so only changed instructions rebuild
  4. D.Layer caching — a minimal base image with no shell or package manager, shrinking attack surface for production
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16. What is Multi-stage build?

Mid
  1. A.a text file of instructions (FROM, RUN, COPY, CMD) that defines how an image is built
  2. B.the Open Container Initiative standard format that lets images run across Docker, containerd and CRI-O
  3. C.a bind mount maps a host path into the container; a volume is Docker-managed storage that survives container removal
  4. D.a Dockerfile pattern using multiple FROM stages to keep build tools out of the final slim image
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18. Which statement is correct?

Mid
  1. A.Multi-stage build — a text file of instructions (FROM, RUN, COPY, CMD) that defines how an image is built
  2. B.Multi-stage build — a bind mount maps a host path into the container; a volume is Docker-managed storage that survives container removal
  3. C.Multi-stage build — a runnable instance of an image with its own writable layer, network and process space
  4. D.Multi-stage build — a Dockerfile pattern using multiple FROM stages to keep build tools out of the final slim image
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19. What is Bind mount vs volume?

Mid
  1. A.reuse of unchanged image layers across builds so only changed instructions rebuild
  2. B.a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
  3. C.a minimal base image with no shell or package manager, shrinking attack surface for production
  4. D.a bind mount maps a host path into the container; a volume is Docker-managed storage that survives container removal
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21. Which statement is correct?

Mid
  1. A.Bind mount vs volume — a bind mount maps a host path into the container; a volume is Docker-managed storage that survives container removal
  2. B.Bind mount vs volume — a text file of instructions (FROM, RUN, COPY, CMD) that defines how an image is built
  3. C.Bind mount vs volume — the Open Container Initiative standard format that lets images run across Docker, containerd and CRI-O
  4. D.Bind mount vs volume — a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
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22. What is Distroless image?

Senior
  1. A.a service such as Docker Hub or ECR that stores and distributes container images
  2. B.a runnable instance of an image with its own writable layer, network and process space
  3. C.a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
  4. D.a minimal base image with no shell or package manager, shrinking attack surface for production
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24. Which statement is correct?

Senior
  1. A.Distroless image — reuse of unchanged image layers across builds so only changed instructions rebuild
  2. B.Distroless image — a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
  3. C.Distroless image — a minimal base image with no shell or package manager, shrinking attack surface for production
  4. D.Distroless image — a Dockerfile pattern using multiple FROM stages to keep build tools out of the final slim image
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25. What is OCI image spec?

Mid
  1. A.a text file of instructions (FROM, RUN, COPY, CMD) that defines how an image is built
  2. B.a read-only template of layers bundling an app and its dependencies, built from a Dockerfile
  3. C.the Open Container Initiative standard format that lets images run across Docker, containerd and CRI-O
  4. D.a Dockerfile pattern using multiple FROM stages to keep build tools out of the final slim image
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27. Which statement is correct?

Mid
  1. A.OCI image spec — a minimal base image with no shell or package manager, shrinking attack surface for production
  2. B.OCI image spec — a Dockerfile pattern using multiple FROM stages to keep build tools out of the final slim image
  3. C.OCI image spec — the Open Container Initiative standard format that lets images run across Docker, containerd and CRI-O
  4. D.OCI image spec — reuse of unchanged image layers across builds so only changed instructions rebuild
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