The document provides an introduction to Linux containers and Docker, explaining their functionalities, benefits, and limitations. It details commands for managing Linux containers with LXC (Linux Containers) and outlines how Docker serves as an application deployment tool that utilizes these containers for efficient resource allocation and image management. Key topics include the lightweight nature of virtualization, network setup, and the integration of Docker for container management.

1. Introduction to Linux Containers & Docker
Jozi Linux User Group – Jan 2014

2. Introduction to Linux Containers
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Makes use of:
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Namespaces:
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User
Network
Hostname
Filesystem
Process table
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Cgroups for resource limits
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Seccomp – filtering of system calls
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AppArmour/SELinux
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Like chroot environment, only more secure and more full featured

3. Introduction to Linux Containers
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Benefits
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Near native performance,
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Application isolation,
Dynamic control of resource allocation, change
during run time and resources only allocated as
used
Limitations
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All use hosts kernel,

4. Introduction to Linux Containers
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apt-get install lxc
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lxc-create -t ubuntu -n <name>
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Templates available - /usr/share/lxc/templates/
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Default user/password: ubuntu/ubuntu
Backing store - /var/lib/lxc
Start a container
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lxc-start -n <name>
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Lxc-start -n <name> -d
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To shutdown issue “shutdown -h now”
Attach lxc-console
Detach via “ctrl-a q”

5. Introduction to Linux Containers
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lxc-ps – List processes running in container
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lxc-ls – List container running on host
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lxc-netstat – List routing table of container
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lxc-freeze – Pause a container
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lxc-unfreeze - Unpause a container
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lxc-shutdown – Shutdown a container
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lxc-destory – Hard stop a container
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lxc-monitor – monitor the state of a container
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lxc-cgroup – change resources allocated to a container
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lxc-clone/lxc-backup/lxc-restore ….

6. Introduction to Linux Containers
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Light-weight virtualisation
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No need for additional kernel nor
hypervisor/translation layer
Network setup similar to virtualisaiton
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Bridged or
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Routed (Natted)

7. Introduction to Linux Containers
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Libvirt integration
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Can connect via
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VNC,
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VT: tty
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Console (ssh,lxc-console)
VT: x
Autostart on startup /etc/lxc/auto

8. What is Docker
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Docker is an application deployment tool that
uses containers,
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Runtime manager for containers,
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Allows for image repository,
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Pushing of incremental changes from
dev,test,production

9. What is docker?
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Docker runs as a
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A daemon to manage lxc containers,
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A cli for creating, managing lxc containers
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A client to access repositories for images

10. What is docker?
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docker search
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docker pull
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docker run
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docker ps
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docker inspect
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docker images
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docker push

11. What is docker?
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docker run ping www.jumpingbean.co.za
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sudo docker run -i -t base/arch /bin/bash
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i interactive
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t terminal
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Sudo docker run -i -t mmckeen/opensuse-13.1 -p 80
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docker port name 8080
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List local host port that has been forwared to 8080
docker run -d

12. What is docker
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Create an account on the repo server
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Create a image on the repo server
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sudo docker login
sudo docker commit $CONTAINER_ID
username/container-name
Update your image on the repo server
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sudo docker push username/container-name