Container images are bound to their parent operating systems
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14
Q
Docker Machine
A
Uses VirtualBox to create VMs that only run Docker
VirtualBox, VM, and VBoxManage knowledge required
Slower than Docker on Linux
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15
Q
Docker Desktop
A
Smaller and more tightly integrated VMs
Automatically handles volume and network port mapping
Comes with a nice GUI
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16
Q
Create a Docker Container (Long Way)
A
Run “docker container create <NAME>"</NAME>
Run “docker ps” to see running containers and “docker ps –all” to see all of them
Run “docker logs <ID>" to see the container log messages</ID>
Run “docker container start –attach” to link the log to the terminal
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17
Q
Create a Docker Container (Short Way)
A
Run “docker run <NAME>" to create a container, start it, and attach its output to the terminal</NAME>
Use “docker ps” to get the container ID
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18
Q
Create a Docker Container from Dockerfiles
A
Run “docker built -t <BUILDNAME> to build a container from the Dockerfile</BUILDNAME>
Add the “–file <FILENAME> flag if the file is named differently</FILENAME>
Docker creates intermediate images after each command and squashes them into a final image at the end
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19
Q
Dockerfile Keywords (FROM)
A
FROM: which existing image to base your image from
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20
Q
Dockerfile Keywords (LABEL)
A
LABEL: additional image data
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21
Q
Dockerfile Keywords (USER)
A
USER: specifies which user to use for subsequent commands
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22
Q
Dockerfile Keywords (COPY)
A
COPY: copies files from the “context” directory to the container image
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23
Q
Dockerfile Keywords (RUN)
A
RUN: command statements to customize the container image
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24
Q
Dockerfile Keywords (ENTRYPOINT)
A
ENTRYPOINT: specifies what command containers from the image should run
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25
Interact with your Container
- Run "docker kill " to forcefully stop a container
- Run "docker run -d " to start the container without attaching it to the terminal
- Run "docker exec " to run additional commands within a container
- Run "docker exec --interactive --tty " to start a new terminal session within a container
26
Stopping and Removing the Container
- By default Docker does not stop and remove a container
- Run "docker stop " to stop a container
- Run "docker stop -t 0 " to forcefully stop a container
- Run "docker rm " to remove a container
- Run "docker rm -f " to remove a container that is running
- Run "docker ps -aq l xargs docker rm" to remove all containers
- Run "docker rmi " to remove an image
27
Binding Ports to your Container
- Add the "--name " flag to the docker run command to name a container
- Add the "-p :" flag to map a port
- "docker run -d --name -p :"S
28
Saving Data from Containers
- Add the "--volume : to map the container
- If you map a non-existing file, Docker will create a new directory on your machine
29
Pushing Images to Docker Hub
- Run "docker tag /: to rename the image
- Run "docker push /: to push to Docker Hub
30
"I can't create more containers"
- Run "docker images" to list images and "docker rmi " to remove images
- Run "docker system prune" to remove unused data
31
"My container is really slow"
- Run "docker stats " to see container stats
- Run "docker top " to see what is running inside the container
- Run "docker inspect " to see advanced information in JSON format
32
Docker Best Practices
- Use verified images
- Use a container image scanner if necessary
- Avoid using the "latest" tag
- Use non-root users
33
Writing a Dockerfile (FROM)
- FROM : specifies which base image to use
34
Writing a Dockerfile (WORKDIR)
- WORKDIR : sets the working directory
35
Writing a Dockerfile (COPY)
- COPY : copies current directory contents into the container
36
Writing a Dockerfile (RUN)
- RUN pip install --no-cache-dir -r requirements.txt
37
Writing a Dockerfile (ENV)
- FLASK_APP=app.py: sets env variable for Flask
38
Writing a Dockerfile (CMD)
- CMD ["flask", "run", "--host=0.0.0.0"]: starts the Flask application
39
Searching for Images in the Docker Hub
Run "docker search "
40
Other Docker Hub Image Search Flags
- "--limit x": limits to x results
- "--no-trunc": returns full image descriptions
- "--format": formats results using Go template
41
Docker Hub Image Search Filters
- "--filter is_official=true": filters by official images
- "--filter stars=x": filters by minimum stars
- "--filter is_automated=true": filters by images that can be built automatically
42
Working with Custom Images
- Run "docker images ls" to see local images
- "--all" flag to see intermediate images
- "--quiet" flag to only return image IDs
- "--filter before=" to filter images before
- "--filter after=" to filter images after
- "--filter dangling=true" to filter unused images
- "--filter label=
43
Tagging and Labeling Images
- Tags specify the version of an image
- Run "docker build -t :" to add a tag
- Run "docker tag ::" to add a tag
44
Working with a Private Image Repository
- Run "docker login"
- Tag the local repository using the name of the repository: "docker tag :/:"
- Run "docker push /:
45
Inspecting Images
- Run "docker image inspect "
- Run "docker image inspect --format='{{json.Config.Labels}}' " to return a specific section in json format
46
Inspecting Images (RepoTags)
- List all tags associated with the image ID
47
Inspecting Images (ContainerConfig)
- Container information
48
Inspecting Images (Config)
- Environment settings
49
Inspecting Images (Cmd)
- Command run when starting a container based on the image (configured in Dockerfile)
50
Inspecting Images (Labels)
- Image labels
51
Removing Images
- Run "docker rmi to remove an image"
- Add the "-f" flag to remove an image attached to a running container
- Run "docker rmi " to remove all tags from an image
52
Start an Existing Container
- Run "docker start"
53
Create and Start a Container
- Run "docker run"
54
Gracefully Stop a Container
- Run "docker stop"
55
Forcefully Stop a Container
- Run "docker kill"
56
List all Running Containers
- Run "docker ps"
- The "-a" flag includes stopped containers
- The "-n" flag returns the last x created containers
- The "-q" flag displays only container IDs
- The "-s" flag displays the total file size of all containers
- The "-l" flag shows the last created container
57
Inspecting Containers
- Run "docker inspect "
- Can return a specific section in json format similar to inspect image
58
Inspecting Containers (ID)
- Container ID
59
Inspecting Containers (State)
- Status flags and PID
60
Inspecting Containers (Image)
- The image that the container is running
61
Inspecting Containers (LogPath)
- Path to the container log
62
Inspecting Containers (Name)
- Name of the container
63
Inspecting Containers (RestartCount)
- The number of times a container has restarted
64
Inspecting Containers (HostConfig)
- How the container will interact with the host system
65
Inspecting Containers (Config)
- Runtime configuration options
66
Reviewing Container Log Files
- Run "docker logs " to view container logs
- The "tail" option specifies last x lines to show
- The "f" option continues streaming new output
- The "details" option shows extra log details
- The "since" option shows logs after a specified time
- The "until" option shows logs until a timestamp
- The "timestamps" option shows timestamps in logs
67
Working with Volumes
- A volume is a directory on the host machine that is accessible by a container
68
Create a Volume
- Run "docker volume create"
69
View Existing Volumes
- Run "docker volume ls"
70
Inspect a Volume
- Run "docker volume inspect "
71
Attach a Volume to a Container
- Add "-v :"
72
Remove an Unused Volume
- Run "volume rm "
73
Working with Mounts
- Use "-v" or "--mount" to bind a host directory to a container directory
- "-v" will create a new directory if it doesn't exist on the host, while "--mount" will return an error
- Run "docker exec -it sh" to open a shell in the container and verify the mount binding worked
74
Daily Docker Workflow
- Run "docker image prune" to remove untagged and unreferenced images
- Add "-a" flag to remove all unused images
- Run "docker container prune" and "docker volumes prune" in similar ways
- Run "docker system prune" to remove unused images, containers, and networks
- Add "--volume" flag to prune volumes
