Docker

Docker Interview Questions and Answer Part – 31

January 22, 2020 comments off

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
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