Talk:LXD configuration for OSM Release TWO

Summary

This is a work-in-progress.

TODO: Why?

LXD is a pure container hypervisor that runs unmodified Linux guest operating systems with VM-style operations at incredible speed and density. This makes it particularly well-suited for developing complex systems. This can be used to install OSM without tainting your host system with its dependencies. This is called nesting, where our host container can launch containers within itself.

As illustrated below, your Host System (a laptop, a virtual machine, etc), you launch the Host Container, with nesting enabled. Inside the Host Container, we'll launch the containers for OSM: SO, RO, and VCA.

+-----------------------------------+
|                                   |
|           Host System             |
|                                   |
| +-------------------------------+ |
| |                               | |
| |        Host Container         | |
| |                               | |
| | +------+  +------+  +-------+ | |
| | |      |  |      |  |       | | |
| | |  SO  |  |  RO  |  |  VCA  | | |
| | |      |  |      |  |       | | |
| | +------+  +------+  +-------+ | |
| +-------------------------------+ |
+-----------------------------------+

Prepare your host system

Installing LXD

In order to run LXD containers, you need to install lxd and zfs (Ubuntu-only?) for lxd's storage backend.

Ubuntu

sudo apt-get update
sudo apt-get install zfs
sudo apt -t xenial-backports install lxd
newgrp lxd                   # required to log the user in the lxd group if lxd was just installed

Routing

By default, your containers will be assigned IP addresses from the bridge inside the Host Container.

TODO: Add option(s) for routing the traffic: iptables route from Host System to Container, or a new bridge added to the containers?

Advanced

If you want finer-grain control of how LXD is configured, you can omit the `--auto` flag and change the default options:

sudo lxd init
 Name of the storage backend to use (dir or zfs) [default=zfs]:
 Create a new ZFS pool (yes/no) [default=yes]?
 Name of the new ZFS pool [default=lxd]:
 Would you like to use an existing block device (yes/no) [default=no]?
 Size in GB of the new loop device (1GB minimum) [default=15]:
 Would you like LXD to be available over the network (yes/no) [default=no]?
 Do you want to configure the LXD bridge (yes/no) [default=yes]?

Network Bridge

By default, LXD creates a bridge named lxdbr0. You can modify this bridge, such as changing the MTU, and these changes will be reflected on the interfaces of the containers managed by the host container.

Although further customization is possible, default options for LXD bridge configuration will work.

Check the MTU of the LXD bridge (lxdbr0) and the MTU of the default interface. If they are different, adjust the MTU of the LXD bridge accordingly to have the same MTU:

lxc list                         # This will drive initialization of lxdbr0
ip address show ens3             # In case ens3 is the default interface
ip address show lxdbr0
sudo ifconfig lxdbr0 mtu 1446    # Use the appropriate MTU value
sudo sed -i '/ifconfig lxdbr0 mtu/d' /etc/rc.local          # To make MTU change persistent between reboots
sudo sed -i "$ i ifconfig lxdbr0 mtu 1446" /etc/rc.local    # To make MTU change persistent between reboots. Use the appropriate MTU value.

Launch the host container

Launch a container to host the OSM installation:

lxc launch ubuntu:16.04 osmr2 -c security.privileged=true -c security.nesting=true
lxc exec osmr2 bash

Prepare your host container

Before we install OSM, we want to make sure LXD is installed and configured.

LXD

On Ubuntu Xenial, we want to enable backports to install the latest stable version of LXD.

sudo add-apt-repository -u "deb http://archive.ubuntu.com/ubuntu $(lsb_release -cs)-backports main restricted universe multiverse"
sudo apt update
sudo apt upgrade
sudo apt -t xenial-backports install lxd

Next, initialize LXD inside the host container. Unless otherwise noted, the defaults will work fine. ZFS won't work inside a container, but that's okay; we've set it up on the host machine.

sudo lxd init
 Do you want to configure a new storage pool (yes/no) [default=yes]? 
 Name of the new storage pool [default=default]: 
 Name of the storage backend to use (dir, btrfs, lvm, zfs) [default=zfs]: dir
 Would you like LXD to be available over the network (yes/no) [default=no]? 
 Would you like stale cached images to be updated automatically (yes/no) [default=yes]? 
 Would you like to create a new network bridge (yes/no) [default=yes]? 
 What should the new bridge be called [default=lxdbr0]? 
 What IPv4 address should be used (CIDR subnet notation, “auto” or “none”) [default=auto]? 
 What IPv6 address should be used (CIDR subnet notation, “auto” or “none”) [default=auto]? none
 LXD has been successfully configured.

Configuration

And then continue with the Release 2 installation.