Which of the following best decribes a Docker Image?
- A read-write template for starting one or more containers
- A point-in-time snapshot of a container used for backups
- A data volume that can be mounted inside of a container
- A read-only template for starting one or more containers (Ans)
You have two services running on a Swarm, but they cannot find each other by name. Which of the following could be the reason why?
- They are on different overlay networks (Ans)
- They were not manually registered with the Swarm DNS when they were created
- Service discovery only works on bridge/NAT networks
- You did not create the Swarm DNS
Which of the following is a loose definition of a Docker container?
- A VM running a shared kernel with resource limits applied
- A unikernel running on a hypervisor with resource limits applied
- An isolated area of an Operating System with resource limits applied (Ans)
What will happen if you start a new container or service and specify a volume that does not currently exist?
- You will be prompted to create the new volume
- The command will complete but the container/service will fail to start
- The command will fail
- Docker will create the volume for you (Ans)
What are the base requirements to be able to use Docker Secrets?
- Swarm mode and an external CA
- Swarm mode and self-encrypting disks for the cluster store
- Docker in Swarm mode (Ans)
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?
- 3 (Ans)
Which of the following best describes a Bridge (NAT on Windows) network in Docker?
- 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?
- 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)
Which are the two major kernel building blocks that containers are built from?
- Capabilities and seccomp
- Namespaces and kernels
- Namespaces and control groups (Ans)
- Capabilities and control groups
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)
- 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