Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
SlideShare a Scribd company logo

Docker for mere mortals

•
•
Henryk Konsek
Henryk Konsek

This document discusses Docker, including: 1. Docker is a platform for running and managing Linux containers that provides operating-system-level virtualization without the overhead of traditional virtual machines. 2. Key Docker concepts include images (immutable templates for containers), containers (running instances of images that have mutable state), and layers (the building blocks of images). 3. Publishing Docker images to registries allows them to be shared and reused across different systems. Volumes and networking allow containers to share filesystems and communicate.

1 of 53
Broughttoyou byHenrykKonsek Docker For mere mortals.
hekonsek@gmail.com | @hekonsek
● What is Docker ● Background ● Key concepts + first steps ● Layers ● Publishing images ● Volumes ● Networking ● Good practices This session
What is Docker
Server for running and managing Linux containers. What is...
Operating-system-level virtualization. What are Linux containers?
chroot on steroids + some kernel magic What are Linux containers?
● slooooooow ● gigantic images ● aggressive resource allocation ● bad API Why not regular virtualization?
Background
Created by this dude Solomon Hykes
Based on LXC Docker team created their own LXC using Go.
Key concepts + first steps
Container is the running image. Key concepts ● image (immutable, no state) ● container (mutable, has state)
Container is the running image. Key concepts
Archived filesystem + metadata. Docker image
No memory snapshots! Docker image
Like Git, but for containers. Commands
Install Docker on Ubuntu. Before you start $ curl -sSL https://get.docker.com/ | sh $ service docker start $ docker version
Let’s run Dockerized shell in new container. Dockerized shell using base image $ docker run -it ubuntu /bin/bash
Docker container == pimped Unix process
Start ‘top’ process in Docker. See/kill it from the host. Docker container == pimped Unix process $ docker run -it ubuntu /bin/bash $ top $ ps aux | grep top $ sudo kill -9 <TOP_PID>
Let’s run daemon process in the new container. Daemon process using base image $ docker run -it ubuntu /usr/bin/top
Let’s run daemon process in the backgronud. Then kill it. Background daemon process using base image $ docker run -d -it ubuntu /usr/bin/top $ docker ps $ docker stop <containerId> $ docker start <containerId>
Tail into the running process. See background process output $ docker run -d -it ubuntu /usr/bin/top $ docker ps $ docker logs -f <containerId>
Layers
Layers WAR Tomcat JRE Ubuntu base
Let’s containerize the execution of process. Dockerized command execution FROM ubuntu RUN apt-get update -qqy RUN apt-get install -qqy cowsay ENTRYPOINT ["/usr/games/cowsay"] CMD ["I'm development cow!"] '' $ docker build -t mycow . $ docker run -t mycow $ docker run -t mycow 'I am production cow!'
Copy and display host’s fstab. Add files to the container FROM ubuntu ADD fstab /tmp/copied_fstab ENTRYPOINT ["cat", "/tmp/copied_fstab"] $ docker build -t fstaber . $ docker run -t fstaber $ cp /etc/fstab fstab
Publishing images
Just like Git repositories :) . Registries.
Create your DockerHub (http://hub.docker.com) account. Before we start
Push to the DockerHub with the latest tag. Push to the DockerHub registry docker login docker build -t hekonsek/test:1 . docker tag -f hekonsek/test:1 hekonsek/test:latest docker push hekonsek/test
Volumes
How can containers share the file system?
You can share filesystem between host and containers. Mounting host filesystem $ docker run -v /etc:/etc-from-host -it ubuntu /bin/bash $ ls /etc-from-host
Provided by the database community/vendor. How can I get database image? $ docker run -d -p 27017:27017 --name mongodb mongo $ apt-get install mongodb-clients $ mongo ]
Mount volume container. Mounting volumes docker run -v /data/db --name mongodb_data busybox true docker run -d --volumes-from mongodb_data -p 27017:27017 --name mongodb mongo
Browse data from the volume. Mounting volumes $ docker run --volumes-from mongodb_data -it ubuntu /bin/bash $ ls /data/db
Create backup of the MongoDB data. Backups $ docker run --volumes-from mongodb_data -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar /data
Networking
ip a | grep docker Virtual ethernet bridge
Containers can access Internet. Internet can’t access containers. Containers are behind of kinda NAT
Docker server can forward ports from containers. Remember MongoDB? $ docker run -d -p 27017:27017 --name mongodb mongo
Let the cow count items in collection using linked MongoDB. How container A can access the network of container B? $ docker run --link mongodb:mongodb -it ubuntu /bin/bash $ apt-get update -qqy $ apt-get install -qqy mongodb-clients $ apt-get install -qqy cowsay $ echo 'db.foo.count()' | mongo mongodb:27017 | /usr/games/cowsay
Kubernetes for the rescue. Networking is hard
Good practices
The generic approach to connect to the service from your application. Connections failover env:MONGODB_SERVICE_HOST # Kubernetes / Custom mongodb # linked container localhost # localhost
The order of the instructions in Dockerfile is important. Build with the caching in mind $ docker build ...
Immutable deployment. Use ENV variable to the container. Build once. Run everywhere.
Docker Maven plugin by Roland ‘Jolokia’ Huß How can I put a fresh jar into an image?
How can I put a fresh jar into an image? <image> <name>${project.artifactId}:${project.version}</name> <build> <from>hekonsek/fatjar:0.0.10-SNAPSHOT</from> <assemblyDescriptorRef>artifact</assemblyDescriptorRef> <exportDir>/jars</exportDir> </build> </image> mvn docker:buid docker:push
docker rmi $(docker images -q) Remove images from time to time :)
Thank you!

More Related Content

Docker for mere mortals

  • 3. ● What is Docker ● Background ● Key concepts + first steps ● Layers ● Publishing images ● Volumes ● Networking ● Good practices This session
  • 5. Server for running and managing Linux containers. What is...
  • 7. chroot on steroids + some kernel magic What are Linux containers?
  • 8. ● slooooooow ● gigantic images ● aggressive resource allocation ● bad API Why not regular virtualization?
  • 10. Created by this dude Solomon Hykes
  • 11. Based on LXC Docker team created their own LXC using Go.
  • 12. Key concepts + first steps
  • 13. Container is the running image. Key concepts ● image (immutable, no state) ● container (mutable, has state)
  • 14. Container is the running image. Key concepts
  • 15. Archived filesystem + metadata. Docker image
  • 17. Like Git, but for containers. Commands
  • 18. Install Docker on Ubuntu. Before you start $ curl -sSL https://get.docker.com/ | sh $ service docker start $ docker version
  • 19. Let’s run Dockerized shell in new container. Dockerized shell using base image $ docker run -it ubuntu /bin/bash
  • 20. Docker container == pimped Unix process
  • 21. Start ‘top’ process in Docker. See/kill it from the host. Docker container == pimped Unix process $ docker run -it ubuntu /bin/bash $ top $ ps aux | grep top $ sudo kill -9 <TOP_PID>
  • 22. Let’s run daemon process in the new container. Daemon process using base image $ docker run -it ubuntu /usr/bin/top
  • 23. Let’s run daemon process in the backgronud. Then kill it. Background daemon process using base image $ docker run -d -it ubuntu /usr/bin/top $ docker ps $ docker stop <containerId> $ docker start <containerId>
  • 24. Tail into the running process. See background process output $ docker run -d -it ubuntu /usr/bin/top $ docker ps $ docker logs -f <containerId>
  • 27. Let’s containerize the execution of process. Dockerized command execution FROM ubuntu RUN apt-get update -qqy RUN apt-get install -qqy cowsay ENTRYPOINT ["/usr/games/cowsay"] CMD ["I'm development cow!"] '' $ docker build -t mycow . $ docker run -t mycow $ docker run -t mycow 'I am production cow!'
  • 28. Copy and display host’s fstab. Add files to the container FROM ubuntu ADD fstab /tmp/copied_fstab ENTRYPOINT ["cat", "/tmp/copied_fstab"] $ docker build -t fstaber . $ docker run -t fstaber $ cp /etc/fstab fstab
  • 30. Just like Git repositories :) . Registries.
  • 31. Create your DockerHub (http://hub.docker.com) account. Before we start
  • 32. Push to the DockerHub with the latest tag. Push to the DockerHub registry docker login docker build -t hekonsek/test:1 . docker tag -f hekonsek/test:1 hekonsek/test:latest docker push hekonsek/test
  • 34. How can containers share the file system?
  • 35. You can share filesystem between host and containers. Mounting host filesystem $ docker run -v /etc:/etc-from-host -it ubuntu /bin/bash $ ls /etc-from-host
  • 36. Provided by the database community/vendor. How can I get database image? $ docker run -d -p 27017:27017 --name mongodb mongo $ apt-get install mongodb-clients $ mongo ]
  • 37. Mount volume container. Mounting volumes docker run -v /data/db --name mongodb_data busybox true docker run -d --volumes-from mongodb_data -p 27017:27017 --name mongodb mongo
  • 38. Browse data from the volume. Mounting volumes $ docker run --volumes-from mongodb_data -it ubuntu /bin/bash $ ls /data/db
  • 39. Create backup of the MongoDB data. Backups $ docker run --volumes-from mongodb_data -v $(pwd):/backup ubuntu tar cvf /backup/backup.tar /data
  • 41. ip a | grep docker Virtual ethernet bridge
  • 42. Containers can access Internet. Internet can’t access containers. Containers are behind of kinda NAT
  • 43. Docker server can forward ports from containers. Remember MongoDB? $ docker run -d -p 27017:27017 --name mongodb mongo
  • 44. Let the cow count items in collection using linked MongoDB. How container A can access the network of container B? $ docker run --link mongodb:mongodb -it ubuntu /bin/bash $ apt-get update -qqy $ apt-get install -qqy mongodb-clients $ apt-get install -qqy cowsay $ echo 'db.foo.count()' | mongo mongodb:27017 | /usr/games/cowsay
  • 45. Kubernetes for the rescue. Networking is hard
  • 47. The generic approach to connect to the service from your application. Connections failover env:MONGODB_SERVICE_HOST # Kubernetes / Custom mongodb # linked container localhost # localhost
  • 48. The order of the instructions in Dockerfile is important. Build with the caching in mind $ docker build ...
  • 49. Immutable deployment. Use ENV variable to the container. Build once. Run everywhere.
  • 50. Docker Maven plugin by Roland ‘Jolokia’ Huß How can I put a fresh jar into an image?
  • 51. How can I put a fresh jar into an image? <image> <name>${project.artifactId}:${project.version}</name> <build> <from>hekonsek/fatjar:0.0.10-SNAPSHOT</from> <assemblyDescriptorRef>artifact</assemblyDescriptorRef> <exportDir>/jars</exportDir> </build> </image> mvn docker:buid docker:push
  • 52. docker rmi $(docker images -q) Remove images from time to time :)