Slides for a quick introduction to Linux containers (lxc) and Docker from a hands-on talk given at the Johannesburg Linux User Group on the 20th Jan 2014

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