A tutorial of Docker for Begineers

Transcript

1. A tutorial of Docker for beginners a.k.a. 夯的搭可⼩小教室 Tsundere Chen 20150912
2. Outline • What is Docker? • What can I do with Docker? • Let’s get started with Docker! • The facts of Docker (containers, namespaces…etc) • Demo Time — WordPress ( NginX + PHP + MySQL) • Something More……
3. Who am I ? • 芦川 光 / 陳⼤大⽴立 • Ashikawa Hikari / Tsundere Chen • http://www.kisekinoashita.org • Python / AngularJS • SOSCET ⽂文書（？
4. OK…So,What is Docker?
7. It’s not ducker, it’s Docker.
8. Build, Ship, and Run Any App, Anywhere
9. Docker Docker containers wrap up a piece of software in a complete filesystem that contains everything it needs to run: code, runtime, system tools, system libraries – anything you can install on a server. This guarantees that it will always run the same, regardless of the environment it is running in. Blah Blah Blah ~~~~
10. Docker ( Again ) • It’s a container, not VM • Portable • Self-Sufficient • Light-Weight • Most important of all, it’s Open Source
11. VMs vs. Docker
12. Why Docker? • Speed! Ship Manual Deploy Auto Deploy Start Bare Metal Couple Days A few hours 15 Minutes 1 Minute Virtual Machine A few minutes A few minutes A few seconds In a minute Docker In seconds In seconds In seconds In seconds
13. Why Docker? • Footprint Normally, you can start • 10 ~ 50 Virtual Machines • 100 ~ 1000 Docker Containers In the same time!
14. Why Docker? • It’s Containerization! Each container has its own • Network interface and IP address • Filesystem • Security • Resource Usage
15. What can I do with Docker? If you are Developer…… • Continous Integration a.k.a. CI • Get rid of Dependency Problem • Everything in Docker
16. What can I do with Docker? If you are Normal User…… • Basically you can do everything just like on a real VM ……but faster.
17. What are we waiting for? Let’s get started!
18. Wait…… Before you start using Docker, here are things you must know. • Images • Containers • Repository
19. Images • Read-only Layer • Loads into container • Commit a container, and you get an image
20. Containers • Container comes from Image • You can create, start, stop, delete container • You can link containers together For example, Web Container can link with SQL Container
21. Repository • Bunch of Images • User Type • Top level Type
22. Let’s get started with Docker! • First, install Docker — curl -sSL https://get.docker.com/ | sh • Let’s pull Debian Jessie ! docker pull debian:jessie • Start a container with bash ! docker run -it debian:jessie bash
23. • After exit a container, list images and containers docker images & docker ps ( -a ) • Daemonize your container docker run -d debian:jessie /bin/sh -c “while true; do echo Hello World!; sleep 1; done;” docker logs <container_id> • Remove your container docker rm <container_id>
24. • Pull this image docker pull kisekinoashita/python2_pip • Use this Image to run Flask, and start a app. It’s already in kisekinoashita/Flask_Demo • Run this image! docker run -d -p 49500:5000 <image> python2 app.py
25. The facts of Docker
26. The facts of Docker • LXC • Cgroups • Kernel namespaces • AUFS
27. LXC • LinuX Container • Create, Start, Console, Stop, Destroy
28. AUFS LXC Docker Base Image (Ubuntu) Base Image (CentOS) Container Image (Apache) Container Kernel
29. But where are cgroups and namespaces ?
30. Namespaces Partition essential kernel structures to create virtual environments For example, you can have multiple processes with PID 234, in different environments Go with “ man namespaces ”
31. What’s in namespaces • pid ( Processes ) • net ( Network Interfaces, Routing ) • ipc ( System V IPC ) • mnt ( Mount Points, Filesystems ) • uts ( Hostname ) • user ( UIDs)
32. Namespaces — pid • Processes in pid can’t see processes of your whole system • Each pid namespace has its own PID #1 • pid namespaces are nested • A process can have multiple PIDs • Different pid namespaces can’t effect others
33. Namespaces — pid Main OS pid 456 pid 456 Container A Container B pid 456 pid 2273 pid 2365
34. Namespaces — net • Each net namespace has its own • Network Interfaces ( and its own localhost ) • IP address • Routing Table • iptables • How to communicate between containers? • UNIX domain sockets • Pairs of Virtual Network interfaces
35. Namespaces — net Docker 0 in Main OS Physical Network Interface eth0 in Container A eth0 in Container B
36. Namespaces — ipc • System V IPC • Recently, POSIX superseded IPC • Some stuff still use legacy IPC
37. Namespaces — ipc Container A Container B App A App B App A App B
38. Namespaces — mnt • A Better chroot • A mnt namespace can have its own rootfs • Filesystem in mnt namespace is visible only in this namespace • We will explain Filesystem with AUFS later
39. Namespace — uts • Hm…Just Hostname • It’s useful when you have thousands of containers and you need to use THAT one
40. Namespace — user • UID 42 in A container isn’t UID 42 in B container • It’s isolated too!
41. Next, we will talk about cgroups
42. Still awake?
43. CAT~~
44. cgroups • Resource limit • Prioritization • Accounting • Control • Isolation
45. cgroup — memory • Limit • Memory usage, Swap usage • Soft limit or Hard limit • Account • Measure how many resource you use • Isolation • “ Get Off My RAM !” • Reserve Memory because of Hard limit
46. cgroup — cpu • Limit • cpu.shares • Account • cpustat.usage • Isolation • cpuset.cpus
47. cgroup — Block I/O • Limit • blkio.throttle.{read,write}.{iops,bps}device • Drawback: only for sync I/O • Account • Number of I/Os, bytes, service time • Drawback: same as Limit • Isolation • Same as Limit Cgroup isn’t best solution of limiting I/O
48. Last, we are going to talk about AUFS
49. AUFS • Base on UnionFS • Read-Only Base, but Read-Write Directory • Your new data will be in /tmp/aufs
50. AUFS — example mount -t aufs \ -o br=/containers/leguest/rw=rw:/images/ubuntu-rootfs=ro \ none /containers/leguest/rootfs Now, if you write in rootfs, changes will go into rw.
51. AUFS — Benefit • Use a single image • Get a Read-Write Filesystem • Nice to Page Cache • Track your changes easily
52. — from @jpetazzo’s slide “AUFS is the worst union filesystems out there; except for all the others that you have been tried”
53. So…is it all? Docker only use these stuff?
54. Remember this?
55. Docker — Isolation tools • systemd-nspawn • libvirt-lxc • libvirt-sandbox • qemu / kvm • BSD Jails • Solaris Zones • chroot
56. Demo Time! WordPress ( NginX + PHP + MySQL)
57. Wait! Something more……
58. Docker has … • Docker Kitematic ( GUI for OS X and Windows(beta) ) • Docker Compose ( used to be “ Fig ” ) • Docker Machine ( A Machine tweaked for Docker ) • Docker Swarm ( Host Clustering and Container Management ) • Docker Registry ( Registry Server )
59. Container OS • Core OS • Rancher OS • Red Hat Project Atomic • VMWare Photon • Snappy Ubuntu Core • Windows Nano Server
60. Some way to use Docker • Copy your stuff into Container, pack it, deploy it on the target Server Remember don’t pack your PERSONAL DATA!!!! • Link your Container together even they are on different Server • Run VPN, Remote Desktop…etc.
61. Questions • Why Docker need OS? • Can we run Docker under Windows environment? • Can I deploy my App to server with Docker? • Is Docker virtualization? • Is Docker really safe?
62. Q & A
63. Thank you 20150912