About the Docker platform

Transcript

1. About the Docker platform Bence Dányi bence@danyi.me github.com/madbence April 8, 2016
2. Introduction to Docker ▶ Docker engine ▶ Docker machine ▶ Docker compose ▶ Docker swarm ▶ Docker hub
3. VM vs container                                    
4. VM vs container VM ▶ Hardware virtualization ▶ Any OS ▶ Overhead (even with hardware support) Container ▶ Operating-system-level virtualization ▶ Shared kernel ▶ Almost no overhead
5. Short history ▶ Solomon Hykes ▶ dotCloud (PaaS) internal project ▶ 2013: open source ▶ 2016: 30000+ github stars, 1300 contributors
6. The architecture        
7. Docker image ▶ Analogy: A VM snapshot ▶ Read-only layers ▶ Union File System ▶ Storage driver: AUFS, OverlayFS, devicemapper, etc.     
8. Docker container ▶ Analogy: A running VM ▶ Isolated from the host ▶ But uses the same kernel (it’s not virtualization!) ▶ Linux host & Linux container ▶ Execution drivers: ▶ LXC ▶ libcontainer ▶ Isolation method: cgroups ▶ Namespace isolation (PID, mount, net, ipc) ▶ Resource limiting (memory, swap) ▶ Prioritization (CPU, I/O) ▶ $ docker run ubuntu echo 'Hello world!'
9. Resource limits ▶ Memory ▶ --memory=128M ▶ --memory-swap=1G ▶ etc. ▶ CPU ▶ --cpu-quota=10 ▶ --cpu-period=100 ▶ etc. ▶ I/O device r/w ▶ --device-write-bps=1mb ▶ etc.
10. Interactions with containers: Network ▶ $ docker network [...] ▶ Types: ▶ Bridged ▶ Overlay (software defined network) ▶ Works between hosts! ▶ VXLAN: Layer-2 (Ethernet) frames embedded into Layer-4 (UDP) frames ▶ Custom (via plugins) ▶ Discover container by name: --name [name] ▶ Built-in DNS server ▶ Expose port on the host: -p [host]:[guest]
11. Interactions with containers: Data volumes ▶ Declare volume in container A ▶ $ docker run -v [/path/to/volume] --name A [...] ▶ Import volumes from A in container B ▶ $ docker run --volumes-from A --name B [...] ▶ Mount host path inside container ▶ $ docker run -v [/host/path/]:[/container/path] [...]
12. Building Docker Images $ docker run [...] $ docker commit [container] [...] $ docker tag [image] [name]
13. Dockerfiles ▶ Programmatically building images (ADD, RUN, CMD, etc.) ▶ $ docker build -t [name] . FROM ubuntu RUN apt-get update && \ apt-get install htop CMD htop
14. Docker Machine ▶ Automatic Docker host provisioning ▶ Providers: ▶ VirtualBox ▶ VMWare ▶ Hyper-V ▶ Azure ▶ OpenStack ▶ Digital Ocean ▶ etc.                 
15. Docker Machine ▶ Create: ▶ $ docker-machine create --driver virtualbox felho ▶ Activate: ▶ $ docker-machine env felho ▶ Manage: ▶ $ docker-machine start felho ▶ $ docker-machine stop felho
16. Docker Compose ▶ Orchestration of multiple containers ▶ Describes services with a declarative syntax (docker-compose.yml) ▶ $ docker-compose up ▶ $ docker-compose down
17. Docker Swarm ▶ Clustering: a single virtual Docker from a Docker host pool ▶ Discovery backend: maintains the list of nodes ▶ Swarm manager: virtual Docker host ▶ Swarm agent: advertises itself
18. Docker Swarm                      
19. Container filters & strategies ▶ Stategy: general algorithm to assign containers to hosts ▶ spread, binpack, random, etc. ▶ Filter: assign containers to hosts based on constraints: ▶ constraint:storage==ssd ▶ affinity:container==mycontainer ▶ affinity:image==~redis ▶ etc.
20. Docker Swarm example setup          
21. Docker Hub ▶ The official image repository ▶ Everyone can push images (user/image:tag) ▶ Automatic image build process (using Dockerfiles) ▶ Open source, you can host your own repository! ▶ Public & private visibility
22. Questions? github.com/madbence/viiima05-preso