Images contain the entire user space, in other words the entire file system for a container. How is this not horribly inefficient in terms of disk space?
- Images are layered and common layers are shared (Ans)
- Images use state of the art compression to reduce the disk space requirements
- You only pull down the image layers that you need to run your application
- Image layers are highly optimized to reduce unnecessary components.
Say you have the following output from docker ps:
57cf9c689955 docs/docker.github.io “/bin/sh -c ‘jekyll s” About an hour ago Exited (137) About an hour ago grave_tesla
Which of the following does not work as a container identifier (CID) when running a command like the following?
docker stop
docker start
docker rm
- 57
- 57cf9c689955
- grave_tesla
- gra (Ans)
How do you terminate software running in a container?
- docker stop (Ans)
- docker rm
- docker terminate
- docker kill
Which of the following Windows Features do you need to use Windows Server containers?
- Docker
- Containers (Ans)
- Hyper-V and Containers
- Hyper-V
Which of the following stops all running containers?
- docker stop $(docker ps -q) (Ans)
- docker rmi $(docker ps -q)
- docker halt $(docker ps -q)
- docker rm -f $(docker ps -q)
Where do dangling volumes typically come from?
- Containers that we manually mount managed volumes into
- Images that have a VOLUME instruction (Ans)
- Containers that we bind-mount host volumes into
- Every container that is created has a volume created as well
Where are created, modified, and deleted files stored in a container?
- In a volume mounted in the container
- In an R/W container layer (Ans)
- In the bottom most layer from the image it was created from
- In the top most layer from the image it was created from
In the past, to launch an installed application, we would run an executable file. How does Docker run software?
- Pull a container
- Install a container
- Runs an executable (Ans)
- Create a container
How are image layers coalesced to form a container’s file system?
- Files are copied out of layers when creating a container into a union mount point
- A union file system is used to create a union mount point (Ans)
- Container file systems exist in memory, in a RAM disk, aggregated from image layers
How can you connect a container to a user defined network?
- –udf NETWORK_NAME
- docker connect
- –net NETWORK_NAME (Ans)
- docker attach
- docker disconnect
In traditional software management, we uninstall software to remove it from a machine, what’s the equivalent with Docker?
- Remove an image
- Uninstall a container
- Remove a container (Ans)
- Stop an image
- Stop a container
When you extract an image with docker save what is inside the tar archive?
- The contents of all layers flattened into one folder
- A folder for the entire image and also a layers folder with each layer nested inside
- A folder for each image layer (Ans)
The docker history command shows output similar to which of the following?
- Dockerfile (Ans)
- docker ps
- docker images
- docker-compose.yml
- docker layers
What is the role of Docker images?
- All of these
- Used to execute code at runtime
- Provides virtualization functionality across environments
- Acts as a blueprint or template that is used to create containers (Ans)
What command can be used to start a container?
- docker run [image name](Ans)
- docker go [image name]
- docker rm [image name]
- docker ps -a
Which of the following tasks can Docker Compose perform?
- View service logs
- None of these
- Build services
- All of these (Ans)
- Start and stop containers
Services can be organized into __ with Docker Cloud.
- groups
- stacks (Ans)
- roles
- zones
What Docker Compose command can be used to start multiple service containers?
- docker-compose up (Ans)
- docker-compose start
- None of these
- docker run
A Docker _ has a “thin R/W layer.”
- File
- Image
- None of these
- Container (Ans)
Each instruction in a Dockerfile creates an intermediate container as the image is built.
- True (Ans)
- False
What syntax can be used to convert a Dockerfile into an Image?
- docker create -t /tagName .
- docker run -t /tagName .
- docker run -t /tagName . (Ans)
- docker convert -t /tagName .
Which of the following tools are included in Docker Toolbox?
- All of these (Ans)
- Docker Machine
- Docker Client
- VirtualBox
- Docker Kitematic
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