Docker

Docker Interview Questions and Answer Part – 20

January 20, 2020 comments off

What type of software deals with running (placement) applications on a given node in the cluster?

  • Placer
  • VM runtime
  • Container runtime
  • Provisioner
  • Scheduler (Ans)

What is the net effect of a separate PID namespace? Each process can have an entirely separate __ .

  • filesystem
  • network stack
  • hostname
  • list of processes (Ans)

How would you avoid port conflicts? Use separate _ namespaces per process.

  • mount
  • PID
  • network (Ans)
  • IPC
  • UTS

How would you avoid shared library conflicts between processes? Use separate _______ namespaces per process.

  • UTS
  • mount (Ans)
  • network
  • PID
  • IPC

What is the net effect of a separate UTS namespace? Each process can have an entirely separate __________ .

  • list of processes
  • filesystem
  • hostname (Ans)
  • IPC
  • IP address

What’s the benefit of a user namespace?

  • Provide each process with its own networking stack and IP addresses
  • Allow privileged operations on resources in the namespaces associated with a process but not system-wide (Ans)
  • Allow privileged operations on all system resources
  • Create users specific to only a given user namespace
  • Provide each process with its own filesystem

What does an app container run?

  • A single application (Ans)
  • Runs the container runtime
  • Runs the host OS init process
  • Runs an OS init process to emulate a VM

What aspect of a scheduler handles app failure?

  • Load Balancing
  • Service Discovery
  • Enforce Desired State (Ans)
  • Scaler

What is a root namespace, i.e. a root network namespace?

  • A namespace for processes run by root, i.e. a network namespace for processes run by root
  • A type of namespace with access to all system resources, i.e. to all network devices in all network namespaces
  • A default namespace, i.e. the default network namespace (Ans)
  • A namespace for root processes, i.e. a network namespace for root processes

What can you use to find vulnerabilities in images?

  • Isolate container networking to avoid malicious processes from talking to other processes
  • Run anti-virus services inside containers
  • Image registries with security scanning (Ans)
  • Image signing and verification

What do cgroups isolate?

  • Which CPUs a process can use
  • None of these
  • Specific device access
  • All of these (Ans)
  • The amount of a resource a process can use

Docker Images consist of read-only layers.

  • False
  • True (Ans)

What task does Docker Machine perform?

  • All of these
  • Find and install Docker images
  • Create and manage local machines (Ans)
  • Create and manage Docker images
  • Create and manage containers

Specific framework versions (Node.js, ASP.NET, etc.) can be loaded on a developer machine by creating a custom Dockerfile.

  • True (Ans)
  • False

What file does Docker Compose use to define services?

  • compose.xml
  • Dockerfile
  • docker- compose.son
  • docker- compose.yml (Ans)

What Dockerfile instruction can be used to execute “npm install” when creating a custom Image?

  • None of these
  • npm install
  • EXECUTE npm install
  • RUN npm install (Ans)

What command- line switches are used with legacy linking?

  • –run and –link
  • –com and –name
  • –link and –name (Ans)
  • –net and –name

Bridge networks can be defined in Docker Compose files.

  • True (Ans)
  • False

Docker Kitematic provides a way to visually search for images hosted on __________?

  • Docker Hub (Ans)
  • VirtualBox
  • Docker Client
  • Docker Machine

Docker containers can be started and stopped.

  • True (Ans)
  • False
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