Docker Interview Questions and Answer Part – 23

Which of the following are top-level keys in a stack file (Compose v3 file)?

• Version, deployments, networks, volumes
• Version and services
• Version, services, networks, volumes (Ans)
• Services, pods, networks, volumes

Which of the following is an advantage of Multi-stage Builds?

• Multi-platform images
• Better image documentation
• Faster image builds
• Smaller images (Ans)

Which of the following is a recommended number of Swarm managers for high availability?

• 4
• 3 (Ans)
• 2

Which of the following best describes a Bridge (NAT on Windows) network in Docker?

• Token-ring
• Multi-host overlay network
• A single-host network (Ans)

How does the HRM know how to route traffic to the correct service?

• iptables rules
• It inspects HTTP host headers (Ans)
• DNS labels
• Custom load balancer rules

By default, where are Docker daemon logs sent to on a Linux system running systemd?

• syslog
• The Linux event viewer
• journald (Ans)

Which of the following is a major goal of Docker volumes?

• Data replication
• Data encryption at-rest
• Object storage
• Persistent data (Ans)
• RAID

Which are the two major kernel building blocks that containers are built from?

• Capabilities and seccomp
• Namespaces and kernels
• Namespaces and control groups
• Capabilities and control groups (Ans)

Which of the following is a recommended best practice?

• Keep your images small (Ans)
• Never use the latest image in a repo
• Use large images containing lots of tools
• Only use Docker Hub

Where are Secrets mounted on Linux-based Docker hosts?

• An encrypted volume mounted at /run/secrets
• An in memory (tempfs) volume at /run/secrets (Ans)
• initramfs
• Solid state volume

How are Docker Secrets created on the command line?

• docker secret create (Ans)
• docker swarm secret create
• They cannot be created on the command line

Which of the following is the best high-level description of a Swarm?

• A secure cluster of Docker nodes (Ans)
• A tightly-coupled cluster of Docker container
• A secure cluster of Docker containers
• I tightly-coupled cluster of Linux nodes

What is the atomic unit of scheduling in Docker?

• The service
• The container (Ans)
• The pod
• The stack
• The swarm

Which of the following commands lets you deploy a Docker Stack called stack1 using a Compose file called myapp.yml?

• docker service deploy -c myapp.yml stack1
• docker stack deploy -c myapp.yml stack1 (Ans)
• docker stack deploy stack1 myapp.yml
• docker service deploy stack1 myapp.yml

Which of the following open-source tools is the underlying technology for Docker Swarm?

• containerd
• SwarmKit (Ans)
• Kubernetes
• InfraKit
• The Docker daemon

Docker UCP implements RBAC via Grants. Which of the following make up a Grant?

• Subjects, roles, and nodes
• Subjects, roles, and collections (Ans)
• Roles and collections

Which of the following built-in Docker networks creates a single layer-2 container-only network across multiple Docker hosts that can be on different underlying networks?

• Bridge
• MACVLAN
• Overlay (Ans)
• NAT

Which Docker command shows the network ports that a container is exposed on?

• docker container ports
• docker port (Ans)
• docker network –port

What happens when you perform a docker volume rm against a volume attached to a running container?

• The command will fail (Ans)
• The volume will be deleted
• The volume and the container will be deleted
• You will be asked to confirm the command

Which set of container-related Linux tools did Docker’s libcontainer replace?

• LXD
• libc
• AUFS
• LXC (Ans)

How can you make a Docker Secret available to a standalone container (not a service replica)?

• You cannot (Ans)
• Make sure it us running on an overlay network
• Make sure it is on a node running in Swarm mode

Which Docker technology allows you to manage an entire application comprising multiple Docker Services?

• Service Mesh
• Stacks (Ans)
• Bundles

Which are the two major Docker container orchestrators?

• Swarm and VMware vSphere
• Swarm and Marathon
• Swarm and Kubernetes (Ans)
• Kubernetes and VMware vSphere

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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