Introduction to Docker
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The document provides an overview of Docker, explaining its architecture, basic commands, and the differences between containers and virtual machines. It details the Docker workflow, including building and running containers, managing images, and pushing images to a registry, along with insights into Linux kernel features that support containerization. Additionally, it touches on orchestration tools, container security, and the benefits of using containers for development and operations.
![DOCKERFILE
Instructions to automate building of your image
Steps are cached for fast-reuse
FROM java:8
COPY target/application.jar app.jar
ENTRYPOINT ["java", "-jar", "app.jar"]](https://image.slidesharecdn.com/dockerintro-160212145422/85/Introduction-to-Docker-20-320.jpg)
Introduction to Docker
- 4. WHAT IS A CONTAINER? Contains the complete runtime environment Application Dependencies
- 5. It feels like a LIGHTWEIGHT VIRTUAL MACHINE It has a shell (SSH, ...) Has its own namespace Has its own network interface Run stuff as root Services Packages But if it's not a VM, so what's the difference?
- 6. VIRTUAL MACHINES App bins/libs Guest OS App bins/libs Guest OS App bins/libs Guest OS Hypervisor Host OS / Kernel Infrastructure
- 7. CONTAINERS Processes that share the same kernel App bins/libs App bins/libs App bins/libs Daemon Kernel Infrastructure
- 10. DOCKER HOST Docker Daemon Docker Remote API (REST) unix:///var/run/docker.sock https://dockerhost:2376 Downloads and runs the containers
- 11. DOCKER CLIENT Talks to Docker daemon
- 12. DOCKER REGISTRY Image repository Official Docker Registry @ hub.docker.com As a service @ Docker Trusted Registry Host your own @ github.com/docker/distribution
- 13. DOCKER IMAGE Basis for each container Layers
- 14. LAYERS Top layer is thrown away when container stops Writeable Container Image: My application Image: Java 8 Base Image: Ubuntu bootfs (Kernel)
- 15. CONTENT ADDRESSABLE IMAGE IDS Previously random UUIDs Secure hash of image and layer data (SHA-256) Separation of images and layers ID collision prevention Data integrity Migration needed from pre-1.10
- 16. VOLUMES Write and read data from outside Mount local folders onto the container Docker Volume drivers available
- 17. Basic Docker
- 18. DEMO TIME!
- 19. Commands
- 20. DOCKERFILE Instructions to automate building of your image Steps are cached for fast-reuse FROM java:8 COPY target/application.jar app.jar ENTRYPOINT ["java", "-jar", "app.jar"]
- 21. BASIC DOCKER COMMANDS # Build the image in the working directory $ docker build -t myapp . # Run the image we just built as a container $ docker run --name mycontainer myapp # Stop the container $ docker stop mycontainer # Start the container again $ docker start mycontainer
- 22. MANAGE CONTAINERS AND IMAGES # List running containers $ docker ps # List all containers, including stopped $ docker ps -a # List all images $ docker images # Remove an image $ docker rmi myapp
- 23. PUSH DOCKER IMAGES TO THE REGISTRY # Login to Docker Registry $ docker login --username=tomverelst --email=tom.verelst@or dina.be # Push the image to the Docker Registry $ docker push myapp
- 25. WARNING Real low-level Linux stuff ahead!
- 26. BACK TO 2007, KERNEL 2.6.24 Control Groups aka cgroups Kernel feature Linux Containers aka lxc Linux package that uses cgroups
- 28. LINUX CONTAINERS Package Different on different Linux distro's
- 29. REDESIGN IN 2013 KERNEL 3.15 AND 3.16 NAMESPACE ISOLATION PID namespace Network namespace Hostname Mount namespace Inter-process communication namespace User namespace
- 30. FIRST DOCKER RELEASE IN 2013 Depended on LXC Now abstracted with libcontainer
- 32. SCALING
- 34. DevOps DEV Application and dependencies Inside of the container OPS Infrastructure Outside of the container
- 35. CONTINUOUS INTEGRATION Same artifact for all environments No more "It worked on my laptop" Run your builds and tests inside containers
- 36. Orchestration Compose Machine Swarm Networking
- 37. Compose Define and run multi-container applications Single host Multi-host experimental
- 38. Machine Create and provision machines as Docker hosts
- 39. Create new Docker hosts Run containers on these new hosts
- 40. Drivers
- 41. Swarm Clustering tool Turn multiple hosts into one virtual host Service discovery Scheduling
- 43. LABELS Define custom labels to your Docker host $ docker daemon --label env="production" --label storage="ssd" $ docker-machine --engine-label env="production" --label storage="ssd" $ docker run -e constraint:env==production -e constraint:storage==ssd ...
- 45. Networking Create overlay networks Replaces links (bridge) Network plugins (Weave) Embedded DNS server
- 48. Tools
- 49. Kubernetes
- 52. etcd etcd etcdDocker Docker Docker CoreOS host CoreOS host CoreOS host Host #1 Host #2 Host #3 etcd fleetctl etcdctl fleetd nServices systemd service files pool Docker containers Docker containers Docker containers Local machine
- 53. Lattice
- 56. CONTAINER SECURITY Isolation Dependencies Seccomp profiles Coming soon: Unikernels Security patches
- 57. NODE SECURITY Daemon must run as root Default authorization is all or nothing Authorization plugins
- 58. Roadmap