LXC and LXD

Table of contents

• Prerequisites
• Install snap
• Install and setup LXD
• Configure the LXD
• Create your first LXD
• Port forwarding

 

Prerequisites

You’ll need the prerequisites installed before you can install snapd and LXD

• yay

 

Install snap

To install the snapd package type the following yay command:

yay -S snapd

Once installed, the systemd unit that manages the main snap communication socket needs to be enabled:

sudo systemctl enable --now snapd.socket

To enable classic snap support, enter the following to create a symbolic link between /var/lib/snapd/snap and /snap:

$ sudo ln -s /var/lib/snapd/snap /snap

Either log out and back in again, or restart your system, to ensure snap’s paths are updated correctly.

 

Confirm service status.

systemctl status snapd.socket

● snapd.socket - Socket activation for snappy daemon
   Loaded: loaded (/usr/lib/systemd/system/snapd.socket; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2019-04-29 17:29:15 EDT; 7h ago
   Listen: /run/snapd.socket (Stream)
           /run/snapd-snap.socket (Stream)
    Tasks: 0 (limit: 4915)
   Memory: 0B
   CGroup: /system.slice/snapd.socket

 

To test your system, install the hello-world snap and make sure it runs correctly:

$ sudo snap install hello-world
hello-world 6.3 from Canonical✓ installed
$ hello-world
Hello World!

Snap is now installed and ready to install LXD

 

Install and setup LXD

Type the following snap command:

sudo snap install lxd

Verify LXD installation

Make sure lxd service enabled on the Arch Linux:

$ sudo snap enable lxd
$ sudo snap services lxd

Service     Startup  Current
lxd.daemon  enabled  active

Add a Linux user named ‘xyz’ to LXD group

Type the following usermod command (feel free to replace the username xyz with your actual username on Arch Linux):

sudo usermod -a -G lxd xyz
id xyz
newgrp lxd

 

$ sudo ln -s /var/snap/lxd/common/lxd /var/lib/lxd

 

Configure the LXD

Type the following command:

lxd init

lxd verification

Make sure the lxc client is talking to the LXD daemon:

lxc list

List all available Linux LXD (Linux Containers) VM images

lxc image list images:

Most of the images are known by several aliases. To see a list, enter:

lxc image alias list images:
lxc image alias list images: | grep -i arch
lxc image alias list images: | grep -i debian
lxc image alias list images: | grep -i fedora

 

Create your first LXD

It is time to create and use your first container. To create and start containers from images use the launch command:

lxc launch images:{distro}/{version}/{arch} {container-name-here}

Let us see some examples to create and start containers from various Linux distro images as per your needs.

CentOS Linux 7 vm

lxc launch images:centos/7/amd64 cenots-7-vm

Fedora Linux 27 vm

lxc launch images:fedora/27/amd64 fedora-27-vm

OpenSUSE Linux 42.3 vm

lxc launch images:opensuse/42.3/amd64 opensuse-42-3

Gentoo Linux vm

lxc launch images:gentoo/amd64 gentoo-linux-vm

Arch Linux vm

lxc launch images:archlinux/amd64 arch-linux-vm

Ubuntu Linux LTS 18.04 VM

lxc launch images:ubuntu/18.10/amd64 ubuntu-nginx-vm

Debian Linux 9.x VM

lxc launch images:debian/9/amd64 debian-nfs-server-vm

How to list all my containers/VMs

List the existing containers:

lxc list --fast
lxc list | grep RUNNING
lxc list | grep STOPPED

How to execute/run the specified command in a container VM

lxc exec containerName -- command
lxc exec containerName -- /path/to/script
lxc exec containerName --env EDITOR=/usr/bin/vim -- command
### run date, ip a, ip rm and other commands on various containers ###
lxc exec cenots-7-vm -- date
lxc exec ubuntu-nginx-vm -- ip r
lxc exec fedora-27-vm -- dnf update
lxc exec debian-nfs-server-vm -- cat /etc/debian_version

How to login to my containers/VMs

To gain login and gain shell access in a container named debian-nfs-server-vm, enter:

lxc exec debian-nfs-server-vm bash

Now you can run commands or install packages for the VM:

# cat /etc/*issue*
# apt-get update
# apt-get upgrade
# apt-get install nginx

To exit simply from container simply type exit:

# exit

How to start/stop/restart my containers

lxc start containerName # <--- start it
lxc stop containerName # <--- stop it
lxc restart containerName # <--- restart it
lxc stop ubuntu-nginx-vm
lxc start ubuntu-nginx-vm
lxc restart ubuntu-nginx-vm
How to delete my containers
lxc stop vmName && lxc delete vmName
lxc stop ubuntu-nginx-vm && lxc delete ubuntu-nginx-vm
Get info about running containers
lxc info
lxc info containerName
lxc info ubuntu-nginx-vm

How to delete my containers

lxc stop vmName && lxc delete vmName
lxc stop ubuntu-nginx-vm && lxc delete ubuntu-nginx-vm

Get info about running containers

lxc info
lxc info containerName
lxc info ubuntu-nginx-vm

 

Port forwarding

First install the nginx server inside ubuntu-nginx-vm:

lxc exec ubuntu-nginx-vm bash
apt update && apt upgrade && apt install nginx
systemctl enable nginx
systemctl status nginx
### update/create the default html file
cat /var/www/html/index.nginx-debian.html

Sample file:

<!DOCTYPE html>
<html>
<head>
 <title>Welcome to nginx running on LXD VM!</title>
</head>
<body>
 <h1><h1>Welcome to nginx running on LXD VM!</h1>
</body>
</html>

Finally logout from the LXD vm:

# logout

Find ubuntu-nginx-vm IP address:

lxc list ubuntu-nginx-vm

Sample outputs:

+-----------------+---------+---------------------+------+------------+-----------+
|      NAME       |  STATE  |        IPV4         | IPV6 |    TYPE    | SNAPSHOTS |
+-----------------+---------+---------------------+------+------------+-----------+
| ubuntu-nginx-vm | RUNNING | 110.55.156.54(eth0) |      | PERSISTENT | 0         |
+-----------------+---------+---------------------+------+------------+-----------+

You need to redirect/forward all incoming traffic on port 80 to Fedora Linux 28 public IP address say 114.50.127.56 to LXD private IP address 110.55.156.54.

Find the default firewall zone

sudo firewall-cmd --get-default-zone
FedoraServer

Open port 80 for FedoraServer zone

sudo firewall-cmd --zone=FedoraServer --add-service=http --permanent

Forward port 80 to the LXD server 110.55.156.54 port 80

sudo firewall-cmd --permanent --zone=FedoraServer --add-forward-port=port=80:proto=tcp:toport=80:toaddr=110.55.156.54

Reload the firewall

sudo firewall-cmd --reload

Test it

Fire the web browser and type url:

http://114.50.127.56

Welcome to nginx running on LXD VM!