Docker

Question 1

Keyword to inherit an image

Answer 1

FROM {image} [as {name}]

Question 2

Keyword to provide defaults to an executing container

Answer 2

CMD

Question 3

“exec” form of CMD

Answer 3

CMD [“executable”, “param1”, “param2”]

Question 4

Form of CMD used to provide default parameters to ENTRYPOINT

Answer 4

CMD [“param1”, “param2”]

Question 5

shell form of CMD

Answer 5

CMD executable param1 param2

Question 6

Keyword for configuring a container which will run as an executable

Answer 6

ENTRYPOINT

Question 7

“exec” form of ENTRYPOINT

Answer 7

ENTRYPOINT [“exe”, “param1”, “param2”]

Question 8

(CLI)Run a new command in an existing container

Answer 8

docker exec -it {container} {cmd}

Question 9

shell form of ENTRYPOINT

Answer 9

ENTRYPOINT exe param1 param2

Question 10

(CLI) Override ENTRYPOINT given in Dockerfile

Answer 10

docker run –entrypoint {entry cmd}

Question 11

(CLI) Connect to shell in new container

Answer 11

docker run -it {img}

Question 12

(CLI) Run a new command in an existing container

Answer 12

docker exec -it {container} {cmd}

Question 13

(CLI) Attach to stdio of running container

Answer 13

docker attach {container}

Question 14

Keyword to execute command in new layer

Answer 14

RUN

Question 15

“exec” form of RUN

Answer 15

RUN [“exe”, “param1”, “param2”]

Question 16

shell form of RUN

Answer 16

RUN {cmd}

Question 17

Keyword to adjust shell used by RUN

Answer 17

SHELL [“exe”, “param”]

Question 18

Default shell used by RUN

Answer 18

[“/bin/sh”, “-c”]

Question 19

Keyword to set the working directory

Answer 19

WORKDIR {path}

Question 20

Default WORKDIR

Answer 20

/

Question 21

Keyword to duplicate files from context into image

Answer 21

COPY

Question 22

Additional capabilities of ADD over COPY

Answer 22

Retrieve from URL; Unpack local tar/bz2/xz archive

Question 23

How to set user/group ownership w/COPY

Answer 23

COPY –chown {uid}:{guid}

Question 24

Prevent invalidation of COPY layer on rebuild

Answer 24

COPY –link

Question 25

Term for dockerfile in which multiple FROM statements are used

Answer 25

Multi-stage build

Question 26

Argument to COPY used to move files between stages of a multi-stage build

Answer 26

FROM {image} As {name}
COPY –from {name}

Question 27

Three types of storage mounts

Answer 27

Volumes, bind mounts, tmpfs mounts

Question 28

“-v” Syntax for a volume mount

Answer 28

-v {vol_name}:{dest}:{options}

{vol_name} may be excluded for anonymous vol

Question 29

”–mount” syntax for a volume mount

Answer 29

–mount type=volume,src={src},dest={dest},ro

Question 30

The main keynames for use with the “–mount” switch

Answer 30

type; src; dest; ro; volume-opt

Question 31

CLI command to create a new volume

Answer 31

docker volume create {vol_name}

Question 32

CLI command to view volume info

Answer 32

docker volume inspect {vol_name}

Question 33

CLI command to delete a volume

Answer 33

docker volume rm {vol_name}

Question 34

CLI switch to create a tmpfs volume

Answer 34

–tmpfs {dest}

Question 35

CLI switch to create a size limited tempfs volume

Answer 35

–mount type=tmpfs,dest={dest},tmpfs-size=xxx

Question 36

Keyword to indicate that a volume should be expected/created at a particular container path

Answer 36

VOLUME [“/path”]
VOLUME /path

Question 37

Keyword to set the default user for subsequent commands

Answer 37

USER {UID}[:{GID}]

Question 38

Here-document syntax

Answer 38

RUN «EOF
apt-get update
apt-get install -y vim
EOF

Question 39

Here-document syntax (non-default shell/interpreter)

Answer 39

RUN «EOF
#!/usr/bin/env python
print(“hello python”)
EOF

Question 40

Create an inline file

Answer 40

COPY «-EOF /path/to/file
{content of file}
EOF

Question 41

Keyword to inform docker of intent to listen on a port at runtime

Answer 41

EXPOSE

Question 42

Default protocol for EXPOSE keyword

Answer 42

tcp

Question 43

Syntax to EXPOSE tcp+udp port

Answer 43

EXPOSE {port}/tcp
EXPOSE {port}/udp

Question 44

CLI flag to map EXPOSED ports to ephemeral high-ordered ports

Answer 44

-P

Question 45

CLI flag to map a port

Answer 45

-p 80:80/tcp -p 80:80/udp

Question 46

Magic file listing files to be excluded from context

Answer 46

.dockerignore

Question 47

Magic file listing files to be excluded from context

Answer 47

.dockerignore

Question 48

Keyword to set an environment variable within build and run stages

Answer 48

ENV {key}={val}
ENV {key} {val}

Question 49

CLI syntax to override an environment variable at runtime

Answer 49

docker run –env {key}={val}

Question 50

Keyword to set an environment variable within only the run stage

Answer 50

ARG {key}[={default_val}]

Question 51

CLI syntax to override a build arg at build time

Answer 51

docker build –build-arg {key}={val}

Question 52

Syntax to use a ENV/ARG variable in a RUN command

Answer 52

RUN echo $var_name

Question 53

Statement to clear an inherited ENTRYPOINT

Answer 53

ENTRYPOINT []

Question 54

How to give a container USB access

Answer 54

docker run -it –privileged -v /dev/bus/usb:/dev/bus/usb {container} {cmd}