Linux containers

Table of Contents Dockers: Overview LXC: Overview Practices Linux Features cgroups Linux namespaces Libcontainer Linux Networking Linux Network Interfaces Linux Network Namespaces

Dockers: Overview

• Wikipedia: https://en.wikipedia.org/wiki/Docker_(software)
• 초보자를 위한 도커
• Slides on linux containers: http://www.haifux.org/lectures/320/netLec8_final.pdf
• Deploying Go servers with docker

  If you would like to use Docker as a non-root user, you should now consider
  adding your user to the "docker" group with something like:
    sudo usermod -aG docker cjeong
  Remember that you will have to log out and back in for this to take effect!

• Nice article on docker: https://www.sitepoint.com/docker-containers-software-delivery

LXC: Overview

• LXC webpage: https://linuxcontainers.org
• Wikipedia: https://en.wikipedia.org/wiki/LXC
• LXC.org getting started: https://linuxcontainers.org/lxc/getting-started/
• Brief LXC intro
• commands
  • create container: lxc-create -t ubuntun -n cn-01
  • start container: lxc-start -n cn-01

  To enable sshd, run: apt-get install openssh-server
  For security reason, container images ship without user accounts
  and without a root password.
  Use lxc-attach or chroot directly into the rootfs to set a root password
  or create user accounts.

Practices

• Google Borg cluster-management system

Linux Features

cgroups

• wiki: https://en.wikipedia.org/wiki/Cgroups

Linux namespaces

• wiki: https://en.wikipedia.org/wiki/Linux_namespaces

Libcontainer

• Libcontainers overview: Golang example

Linux Networking

Linux Network Interfaces

Linux Network Namespaces

• Brief intro to network namespaces
• add namespace: ip netns add BLUE
• list namespace: ip netns list
• assigning network interface to network namespaces:
  • one cannot assign physical network interface to a namespace -- one can only assign virtual Ethernet (veth) interfaces to a network namespace
  • veth always come in pairs, connected like a tube
  • create veth pair: ip link add veth0 type veth peer name veth1
  • list veth pair: ip link list: this "listing" only shows global namespace
• connecting veth-pair network interfaces to namespace:
  • ip link set veth1 netns BLUE
  • now veth1 interface has disappeared from global namespace and put into BLUE namespace
  • so, to see veth* list the BLUE namespace ip netns exec BLUE ip link list
    • ip netns exec <namespace></namespace>: prefix to use when executing command in a namespace
• configuring network interface: ip netns exec BLUE ifconfig veth1 10.1.1./24 up
  • assigns an IP address to veth1 interface and bring that interface up