Docker.ppt
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- Docker is an open platform for developers and sysadmins to build, ship, and run distributed applications. It allows applications to run securely isolated in user-defined containers across any infrastructure. - Docker uses Linux kernel features like cgroups and namespaces to provide isolation and allocate resources only to the containers that "need" them. This makes containers lightweight and efficient. - Docker images are read-only templates that serve as the basis for containers. Images are built from Dockerfiles containing a series of commands to assemble an image. Containers are run from images and are read-write.
Docker.ppt
- 2. • A dotCloud (PAAS provider) project • Initial commit January 18, 2013 • Docker 0.1.0 released March 25, 2013 • 18,600+ github stars, 3800+ forks,740 Contributors…. and continues • dotCloud pivots to docker inc. October 29, 2013 DOCKER HISTORY ……
- 3. • Open platform for developers and sysadmins to build, ship and run distributed applications • Can run on popular 64-bit Linux distributions with kernel 3.8 or later • Supported by several cloud platforms including Amazon EC2, Google Compute Engine, and Rackspace. What is Docker ?!!!
- 4. • Light-Weight o Minimal overhead (cpu/io/network) o Based on Linux containers o Uses layered filesystem to save space (AUFS/LVM) o Uses a copy-on-write filesystem to track changes • Portable o Can run on any Linux system that supports LXC (today). o 0.7 release includes support for RedHat/Fedora family. o Raspberry pi support. o Future plans to support other container tools (lmctfy, etc.) o Possible future support for other operating systems (Solaris, OSX, Windows?) • Self-sufficient o A Docker container contains everything it needs to run o Minimal Base OS o Libraries and frameworks o Application code o A docker container should be able to run anywhere that Docker can run. Features….
- 6. The Matrix From Hell……
- 8. Also a Matrix from Hell……
- 9. Solution: Intermodal Shipping Container……
- 10. Docker is a Container System for Code……
- 11. Docker Eliminates the Matrix from Hell……
- 12. Why it Works: Separation of Concerns……
- 13. • Docker Engine – CLI – Docker Daemon – Docker Registry • Docker Hub – Cloud service • Share Applications • Automate workflows • Assemble apps from components • Docker images • Docker containers Docker Architecture……
- 14. • NOT A VHD • NOT A FILESYSTEM • uses a Union File System • a read-only Layer • do not have state • Basically a tar file • Has a hierarchy • Arbitrary depth • Fits into the Docker Registry Docker images……
- 15. Units of software delivery (ship it!) ● run everywhere – regardless of kernel version – regardless of host distro – (but container and host architecture must match*) ● run anything – if it can run on the host, it can run in the container – i.e., if it can run on a Linux kernel, it can run *Unless you emulate CPU with qemu and binfmt Docker Containers...
- 17. Containers after Docker ……
- 18. How does Docker work ? • You can build Docker images that hold your applications • You can create Docker containers from those Docker images to run your applications. • You can share those Docker images via Docker Hub or your own registry
- 19. Virtual Machine Versus Container……
- 20. Virtual Machine Versus Container……
- 21. • The Life of a Container – Conception • BUILD an Image from a Dockerfile – Birth • RUN (create+start) a container – Reproduction • COMMIT (persist) a container to a new image • RUN a new container from an image – Sleep • KILL a running container – Wake • START a stopped container – Death • RM (delete) a stopped container • Extinction – RMI a container image (delete image) Docker Container Lifecycle ……
- 22. • Kernel Feature • Groups of processes • Control resource allocations – CPU – Memory – Disk – I/O • May be nested Linux Cgroups ……
- 23. • Kernel Feature • Restrict your view of the system – Mounts (CLONE_NEWNS) – UTS (CLONE_NEWUTS) • uname() output – IPC (CLONE_NEWIPC) – PID (CLONE_NEWPID) – Networks (CLONE_NEWNET) – User (CLONE_NEWUSER) • Not supported in Docker yet • Has privileged/unprivileged modes today • May be nested Linux Kernel Namespaces ……
- 24. • Like a Makefile (shell script with keywords) • Extends from a Base Image • Results in a new Docker Image • Imperative, not Declarative • A Docker file lists the steps needed to build an images • docker build is used to run a Docker file • Can define default command for docker run, ports to expose, etc Dockerfile ……
- 25. Docker CLI Commands (v1.1.2)……
- 26. Want to hack on Docker ? • Reporting Security Issues • Design and Cleanup Proposals • Reporting Issues • Build Environment Contributing to Docker ……
- 27. • Easy to build, run & share containers • Rapidly expanding ecosystem • Better performance vs. VMs • Layered file system gives us git-like control of images • Reduces complexity of system builds • Red Hat - Project Atomic Host, and certifications - containerized applications, Geard and OpenShift. • Google is expected to tightly integrate containers with its IaaS and PaaS offerings. SUMMARY……