Virtualization using LXC

LXC Host Details

hostname: infrabase1 Network: 172.16.149.128/25 IP Address : 172.16.149.176 Subnet Mask: 255.255.255.128 Gateway: 172.16.176.129 DNS: 8.8.8.8 Server OS: Ubuntu 18.04 Edition: LTS, server sudo user: kedar FTP Client: Filezilla ssh client: terminal, reminna Text editors: gedit, sublime-text <strongUser PC Details</strong> PC type: Desktop OS: Ubuntu Desktop IP Address: 172.16.162.65 sudo user:kedar

Introduction

LXC (Linux Containers) is an operating system level virtualization method for running several isolated Linux systems (containers) on a host running a linux operating system. The containers use the kernel of the host operating system and hence lxc does not have to virtualize the entire hardware of the host. Containers are relatively low on resource requirement and a singe host has the ability to run a very dense container environment, running several containers as opposed to a conventional KVM based virtualization. More information is available on here.

Preparing lxc Host

• ssh from local machine to the lxc host

ssh kedar@172.16.149.176

• Ensure infrabase1 (host server) is updated with latest patches and updates

sudo apt update && sudo apt upgrade -y

• Remove unwanted software

sudo apt autoremove

• Restart the host server

sudo init 6

Installing lxc

• Install lxc using the ubuntu repositories

sudo apt install lxc

Creating Containers

• Create a container called as apache. This container will be used as a webserver and apache will be installed as a webserver. You can name the container as you like.

sudo lxc-create -t download -n apache -- -d ubuntu -r bionic -a amd64

Useful commands

Container status modification

• sudo lxc-start -n apache
• sudo lxc-stop -n apache
• sudo lxc-destroy -n apache This will work only if the container is in stopped state.
• sudo lxc-ls --fancy to get te IP addresses of the running containers.

Logging into the container

• sudo lxc-start -n apache This will start the container
• sudo lxc-attach -n apache This will log you in the container as root
• Important to note that only root user is enabled in the container. You will have to create a user if you like
• Creating a user while logged into the container. Run the below commands as root in the container

adduser kedar It will ask you many questions, Generally keep the default

• Add the user in sudoer group

usermod -aG sudo kedar

• Install necessary software like openssh server so that you can ssh into the container

apt install openssh-server systemctl status shhd

Conclusion

• Lxc is a great way to understand containers and should be a starting point for users who are interested in container based virtualization
• There are several advantages of using Lxc but it is by design and default that the containers are not accessible from outside the host. To enable that there are two options.
  • Create a network bride
  • Using iptables forward ports to the containers
• Explore Lxc and have fun !