Docker Interview Questions and Answer Part – 31

What is the preferred way to deploy and manage a Docker Stack?

• The declarative way via config files (Ans)
• The imperative way via commands

Which of the following Docker Engine component is a Cloud Native Computing Foundation (CNCF) project?

• containerd (Ans)
• The Docker Remote API
• runc
• The daemon

Which components constitute the control plane aspects of a Docker UCP cluster?

• UCP/Swarm minions
• UCP/Swarm workers
• UCP/Swarm managers (Ans)

Which key combination will disconnect your shell from an interactive container, and return you to the shell of your Docker host without killing the container?

• Ctrl+Z
• Ctrl+C
• Ctrl+esc
• Ctrl+P+Q (Ans)

Which of the following network types would you choose if you needed your containers to be first class on one of your existing VLANs?

• Bridge
• NAT
• MACVLAN (Ans)
• Overlay

What type of storage takes care of a containers union filesystem/union mount?

• Graph driver (snapshotter) (Ans)
• Volume data
• Copy-on-write (CoW)
• Object storage

What happens to the data in a volume when the last container it was connected to is deleted?

• The data remains intact (Ans)
• The data is deleted along with the last container

How can you inspect the unencrypted contents of a Docker secret?

• With the docker secret inspect command on the leader manager in a Swarm
• You cannot (Ans)
• With the docker secret inspect command

Which of the following describes how Docker manages a deployed stack?

• It constantly monitors the state of the stack via reconciliation loops and makes sure actual-state and desired-state match (Ans)
• Swarm checks the health of the stack every 60 seconds to make sure actual-state matches desired-state
• Fire and forget. Once the stack is deployed, it must be monitored via external tools.

What are some of the benefits Docker Trusted Registry (DTR) has over Docker Hub?

• On premises, image promotions (Ans)
• Public and private repos
• Image scanning

Which Docker command lists all of the managers and workers in a Swarm?

• docker swarm info
• docker swarm nodes
• docker node ls (Ans)
• docker swarm ls

Which of the following is the default network a container will join of you don’t override with the –network flag?

• Overlay
• MACVLAN
• Bridge (Ans)
• Wifi

Which two docker container run flags are commonly used to create a container you can log-on to and interact with?

• -ahl
• -it (Ans)
• -ssh
• -telnet

Which of the following describes data that we need to keep long-term?

• Immutable
• Persistent (Ans)
• Ephemeral
• Non-persistent

Where does a container’s graph driver storage usually exist?

• /etc/docker (Linux) and C:\ProgramData\Docker\windowsfilter (Windows)
• /var/lib/docker (Linux) and C:\ProgramData\Docker\windowsfilter (Windows) (Ans)
• /var/run/docker (Linux) and C:\Program Files\Docker\windowsntfs (Windows)

Which of the following describe some of the OS-level constructs that each container gets?

• Process trees, network stacks, and users (Ans)
• Virtual CPU and virtual RAM
• Kernel modes
• Kernel rung buffers and syscall tables

How does the Docker Engine expose the Docker API?

• As a versioned HTTP REST interface (Ans)
• gRPC on a Unix socket

Which of the following describes a potential advantage a Hyper-V container has over a native Windows container?

• You can run a different OS/kernel for each container (Ans)
• They start faster
• They implement open CNCF standards
• You ran run more on a single Windows Docker host

Which of the following best describes a Docker UCP cluster?

• A group of Swarm managers and Kubernetes minions
• A group of Swarm managers and Kubernetes minions
• A cluster of Swarm-based manager and worker nodes (Ans)

What do Swarm managers and workers use their client certificates for?

• Role authorization and cluster join token
• Mutual authentication, role authorization, and transport encryption (Ans)
• Transport encryption
• Mutual authentication and transport encryption

How many processes does a Linux-based Docker container normally run?

• One per image layer
• One (Ans)
• Two

How can you login to your local DTR so that you can push and pull images from it?

• docker login (Ans)
• dtr login
• docker ucp login

How can you make a Swarm service accessible from all nodes in a Swarm on the same port?

• Create enough replicas so that there is one on each Swarm node
• Map the service to a port with the -p flag (Ans)
• Create a global service
• Create an external load balancer

Rajesh Kumar

I’m Rajesh Kumar, a DevOps, SRE, DevSecOps, Cloud, and Platform Engineering expert passionate about sharing practical knowledge, real-world experiences, and industry best practices. I have worked at Cotocus and regularly write about technology, travel, investing, health, product reviews, and digital marketing through my various platforms.

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