Docker2

Question 1

run a container with a command and argument

Answer 1

docker run nginx echo hello world.

Question 2

list all containers

Answer 2

docker ps -a

Question 3

what is the difference between a container and an image?

Answer 3

when a container is created from an image, it adds a new writable layer on top of the image layers. This is called ‘container layer’. the major difference between a container and an image is the top container layer.

Question 4

explain this command docker run -d - -name app1 httpd

Question 5

command to display detailed information of a container.

Answer 5

docker inspect [container name]

Question 6

pause a container

Answer 6

docker pause [cont name]

Question 7

unpause a container

Answer 7

docker unpause [cont name]

Question 8

pull an image

Answer 8

docker pull [image name]

Question 9

inspect an image

Answer 9

docker inspect [image name]

Question 10

what is a Dockerfile?

Answer 10

a set of instructions used to build an image.

Question 11

what are some frequently used docker file instructions?

Answer 11

FROM: sets the parent image
LABEL: adds metadata to the image
EXPOSE: intend port to publish
CMD: setting default command that will run in the container. It can be overridden
ENTRYPOINT: the entry point in a Dockerfile defines what the container should do when it starts, it does not get overridden.
WORKDIR: sets current working directory
COPY: copy files from one location to the container
ENV: sets environment variables
USER: sets user

Question 12

what are the two types of storage ?

Answer 12

non persistent: data resides withing the cont, gets deleted when container is deleted, all containers have it by default
persistent: data does not reside within the container, does not get deleted when the container is deleted

Question 13

what is the syntax to mount volume to a container?

Answer 13

docker run -d - -name [cont name] -v [volume name]:/usr/local/apache2/htdocs/ httpd