ABCs of docker
Download as PPTX, PDF2 likes897 views
This document provides an overview of containerization and Docker. It covers prerequisites, traditional application deployment challenges, container components like namespaces and cgroups, major Docker concepts like images and containers, common Docker commands, building Dockerfiles, and Docker workflows and best practices. Hands-on exercises are included to build and run containers.
![cgroups - Wikipedia
cgroups (abbreviated from control groups) is a Linux kernel feature that limits,
accounts for and isolates the resource usage (CPU, memory, disk I/O, network,
etc.) of a collection of processes.
Engineers at Google (primarily Paul Menage and Rohit Seth) started the work
on this feature in 2006, under the name "process containers".[1] In late 2007
the nomenclature changed to "control groups" due to the confusion caused by
multiple meanings of the term "container" in the Linux kernel context, and
control-group functionality merged into kernel version 2.6.24.[2] Since then,
developers have added many new features and controllers, such as support for
kernfs,[3] firewalling,[4] and unified hierarchy.[5]](https://image.slidesharecdn.com/abcsofdocker-150810171550-lva1-app6891/85/ABCs-of-docker-23-320.jpg)
![Writing own Dockerfile
FROM ubuntu:latest
MAINTAINTER <name surname>
FROM ubuntu:latest
RUN apt-get update
RUN apt-get install -y nginx
CMD ["nginx", "-g", "daemon off;"]](https://image.slidesharecdn.com/abcsofdocker-150810171550-lva1-app6891/85/ABCs-of-docker-58-320.jpg)
![Docker Workflow 1
1) Download file from curl -L -O http://github.com/atbaker/flask-example/archive/master.zip
2) Unzip master.zip
3) run python flask-example.py
Build as docker:
FROM python:2-onbuild
EXPOSE 8000
CMD [“gunicorn”, “-c”, “gunicorn_config.py”, “flask-example:app”]](https://image.slidesharecdn.com/abcsofdocker-150810171550-lva1-app6891/85/ABCs-of-docker-59-320.jpg)
![Docker Workflow 2
Download file from curl -L -O http://github.com/atbaker/django-example/archive/master.zip
Build as docker:
FROM python:2.7-onbuild
EXPOSE 8000
CMD [“gunicorn”, “-c”, “gunicorn_config.py”, “--chdr”, “django-example”, “wsgi:application”]
docker run --name postgres -d postgres:9.3
docker run --name memcached -d atbaker/memcached-verbose
docker run --name django -d -p 8000:8000 --link postgres:db --link memcached:cache django-example
docker run --name django --link postgres:db --link memcached:cache django-example python django/example/manage.py migrate](https://image.slidesharecdn.com/abcsofdocker-150810171550-lva1-app6891/85/ABCs-of-docker-60-320.jpg)
ABCs of docker
- 2. ● Basics of container and Docker ● Major Docker components ● Starting learning basic docker commands ● Hands-on labs and exercises ● Quiz Course outline
- 3. Prerequisites ● Basic knowledge of how OS works, no need to be expert ● At least 1 virtual machine
- 5. A bit of scale makes a bit of scare
- 12. Containers under the hood
- 23. cgroups - Wikipedia cgroups (abbreviated from control groups) is a Linux kernel feature that limits, accounts for and isolates the resource usage (CPU, memory, disk I/O, network, etc.) of a collection of processes. Engineers at Google (primarily Paul Menage and Rohit Seth) started the work on this feature in 2006, under the name "process containers".[1] In late 2007 the nomenclature changed to "control groups" due to the confusion caused by multiple meanings of the term "container" in the Linux kernel context, and control-group functionality merged into kernel version 2.6.24.[2] Since then, developers have added many new features and controllers, such as support for kernfs,[3] firewalling,[4] and unified hierarchy.[5]
- 26. Quiz - Containers What are the benefits of using container instead of VM? ● No need for hypervisor ● No need for operating system ● No physical hardware ● No need for priveleged user ● No. It’s uselles.
- 27. Quiz - Containers What are the benefits of using container instead of VM? ● No need for hypervisor ● No need for operating system ● No physical hardware ● No need for priveleged user ● No. It’s uselles.
- 28. I create process with PID=1234 in container. What PID will be on host OS? a. the same as in container: PID=1234 b. on host there will be PID=4321 that maps to PID=1234 in container c. it wont be created in container. Actually container creates it on host. d. there will be no pid on host. PID=1234 is the child process in container Quiz - Containers
- 29. I create process with PID=1234 in container. What PID will be on host OS? a. the same as in container: PID=1234 b. on host there will be PID=4321 that maps to PID=1234 in container c. it wont be created in container. Actually container creates it on host. d. there will be no pid on host. PID=1234 is the child process in container Quiz - Containers
- 30. What are the main components of namespaces? a. uts, ipc, pid, network, user, mount b. user, pid, mount, filesystem, application, io c. pid, os, hardware, user, internet, filesystem d. mount, hardware, network, user, pid, cgroup Quiz - Containers
- 31. What are the main components of namespaces? a. uts, ipc, pid, network, user, mount b. user, pid, mount, filesystem, application, io c. pid, os, hardware, user, internet, filesystem d. mount, hardware, network, user, pid, cgroup Quiz - Containers
- 32. Quiz - Containers What should i do to run application with unprivileged user in container? a. change the owner to current user and run it b. login as sudo and run the application c. enter the container and run it d. login as sudo then chown the application then run it
- 33. Quiz - Containers What should i do to run application with unprivileged user in container? a. change the owner to current user and run it b. login as sudo and run the application c. enter the container and run it d. login as sudo then chown the application then run it
- 41. In short: write once, really run anywhere
- 42. Docker images and containers
- 43. pull the image from docker cloud servers
- 44. Images repository - Dockerhub
- 45. Installing Docker engine 1. Open https://docs.docker.com/installation/ 2. Find the name of your host operating system from the list 3. Follow the instructions
- 46. Linux: Add current user to docker group sudo gpasswd -a <user_name> docker
- 47. Mac OS: set env variables for boot2docker boot2docker up export DOCKER_HOST=tcp://192.168.59.103:2376 export DOCKER_CERT_PATH=<cert path> export DOCKER_TLS_VERIFY=1 or $(boot2docker shellinit) Get ip of boot2docker: boot2docker ip Check version of docker: docker version
- 48. Windows: maybe like on MacOS...but didnt try boot2docker up set DOCKER_HOST=tcp://192.168.59.103:2376 set DOCKER_CERT_PATH=<cert path> set DOCKER_TLS_VERIFY=1 or boot2docker shellinit Get ip of boot2docker: boot2docker ip Check version of docker: docker version
- 49. Let docker say: Hello World! docker run hello-world
- 50. Now let’s get into the container 1) docker pull centos – fetch centos image from repository 2) docker run centos – run fetched centos image within container 3) docker ps - list the running containers 4) docker ps -a - list all the containers (running + not running) 5) docker exec - to execute the command inside container 6) docker attach - get into the container 7) exit from container quits the container 8) Ctrl+P and Ctrl+Q leaves the running container 9) docker inspect <container_id> - show info about running container
- 51. Lab: Run required container IOS/Android developers: 1) docker run -d –p 8080:8080 jenkins 2) Open http://<docker_host>:8080 in your browser and create build plan in jenkins Service developers: 1) docker run -it --rm williamyeh/scala 2) Write hello world in scala TIP: docker --help is you cheat sheet
- 52. Quiz - Docker What is the difference between images and containers? a. containers consist of binary files, images consist of user app files b. containers run only once, whereas images run multiple times c. containers pulled from dockerhub, whereas images stores locally d. images consist of instructions and user files, whereas containers only runtime environment for user process
- 53. Quiz - Docker What is the difference between images and containers? a. containers consist of binary files, images consist of user app files b. containers run only once, whereas images run multiple times c. containers pulled from dockerhub, whereas images stores locally d. images consist of instructions and user files, whereas containers only runtime environment for user process
- 54. Quiz - Docker What will be the result of the following instructions? docker run -it my-image /bin/bash # let’s say it returns ID 123... echo “Sample text” | cat > SampleText.txt exit docker cp 123:/root/SampleText.txt ./ a. will copy SampleText.txt to current directory b. will copy data from the current directory to /root/SampleText.txt inside container c. prints to screen Sample text and copies SampleText.txt to current directory on docker host d. does nothing. Terminates with error
- 55. Quiz - Docker What will be the result of the following instructions? docker run -it my-image /bin/bash # let’s say it returns ID 123... echo “Sample text” | cat > SampleText.txt exit docker cp 123:/root/SampleText.txt ./ a. will copy SampleText.txt to current directory b. will copy data from the current directory to /root/SampleText.txt inside container c. prints to screen Sample text and copies SampleText.txt to current directory on docker host d. does nothing. Terminates with error
- 56. Quiz - Docker What will be the result of the following instructions? docker run -d my-image /bin/bash echo “Sample text” | cat > SampleText.txt # let’s say returns id 123... docker run -d my-image /bin/bash “ping 8.8.8.8” docker cp 123:/root/SampleText.txt ./ a. will copy SampleText.txt to current directory b. will copy data from the current directory to /root/SampleText.txt inside container c. prints to screen Sample text and copies SampleText.txt to current directory on docker host d. does nothing. Terminates with error
- 57. Quiz - Docker What will be the result of the following instructions? docker run -d my-image /bin/bash echo “Sample text” | cat > SampleText.txt # let’s say returns id 123... docker run -d my-image /bin/bash “ping 8.8.8.8” docker cp 123:/root/SampleText.txt ./ a. will copy SampleText.txt to current directory b. will copy data from the current directory to /root/SampleText.txt inside container c. prints to screen Sample text and copies SampleText.txt to current directory on docker host d. does nothing. Terminates with error
- 58. Writing own Dockerfile FROM ubuntu:latest MAINTAINTER <name surname> FROM ubuntu:latest RUN apt-get update RUN apt-get install -y nginx CMD ["nginx", "-g", "daemon off;"]
- 59. Docker Workflow 1 1) Download file from curl -L -O http://github.com/atbaker/flask-example/archive/master.zip 2) Unzip master.zip 3) run python flask-example.py Build as docker: FROM python:2-onbuild EXPOSE 8000 CMD [“gunicorn”, “-c”, “gunicorn_config.py”, “flask-example:app”]
- 60. Docker Workflow 2 Download file from curl -L -O http://github.com/atbaker/django-example/archive/master.zip Build as docker: FROM python:2.7-onbuild EXPOSE 8000 CMD [“gunicorn”, “-c”, “gunicorn_config.py”, “--chdr”, “django-example”, “wsgi:application”] docker run --name postgres -d postgres:9.3 docker run --name memcached -d atbaker/memcached-verbose docker run --name django -d -p 8000:8000 --link postgres:db --link memcached:cache django-example docker run --name django --link postgres:db --link memcached:cache django-example python django/example/manage.py migrate
- 61. Docker workflow 2 with Docker-Compose django: build: . links: - postgres:db - memcached:cache ports: - “8000:80” postgres: image:postgres:9.3 memcached: image:atbaker/memcached-verbose
- 62. Useful resources https://docs.docker.com/ - official docs from Docker https://docs.docker.com/compose/ - official docs about Docker Compose https://docs.docker.com/docker/introduction/understanding-docker/ - Docker architecture https://linuxcontainers.org/ - WiKi about Linux Containers (LXC) https://lwn.net/Articles/531114/ - Linux namespaces overview https://lwn.net/Articles/532748/ - Linux PID namespaces