Docker Interview Questions and Answer Part – 20

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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