MicroCloud is a solution from Canonical that orchestrates System Containers (LXC) and Virtual Machines (VMs) with Software Defined Networking (SDN) and Software Defined Storage (SDS) platforms.
Despite the name, it supports between 3 and 50 nodes on a single fleet of hosts. The name refers to its small footprint: it delivers a virtualisation platform with high availability and live migration in minutes, with minimal overhead (close to bare-metal performance).
The whole package is open source:
- MicroCloud – orchestrator
- LXD – high-availability computing
- Ceph – distributed storage
- OVN – virtual networking
Requirements / Recommendations:
- 3 hosts (VM, LXC, or bare-metal)
- 4 vCPUs + 4 GB of RAM per host
- 2 network adapters per host
- 1 system volume + 1 local volume + 1 distributed volume per host
INSTALLATION
Start all hosts and connect them to the same network segment via the first network interface. The second network interface must have no IP address assigned (disable DHCP).
MicroCloud and all of its components are Snap packages. Since Snap is the native package manager on Ubuntu, deploy as many hosts as needed with the latest Ubuntu LTS, then run the following commands on all of them.
sudo apt update sudo apt upgrade -y sudo snap install microcloud lxd microceph microovn
On one of the hosts, run the command that scans for eligible hosts to join the cluster.
sudo microcloud init
Follow the prompts and make the necessary adjustments for your environment.
It is recommended to limit the search scope for faster discovery (it uses multicast UDP packets via mDNS).
Select all that apply. There will be no prompt or confirmation on the other hosts.
Besides the system volume, allocate the secondary drive for host-local storage.
Allocate the third volume to Ceph (SDS).
Assign the secondary network adapter to OVN (SDN).
Enter the default gateway and the range of IPs not currently in use (reserved on the DHCP server).
VISUALISATION
sudo microcloud cluster list sudo lxc cluster list sudo microceph cluster list sudo microovn cluster list sudo lxc list sudo lxc storage list sudo lxc storage info local sudo lxc storage info remote sudo lxc network show default sudo lxc network list
UPDATES
Note that snapd (Snap Daemon) automatically checks for new versions in the Snap Store and initiates updates.
Check the currently installed versions:
sudo snap list
In Snap, the refresh argument is equivalent to running update followed by upgrade in apt.
sudo snap refresh --list sudo snap refresh lxd --cohort="+" sudo snap refresh microceph --cohort="+" sudo snap refresh microovn --cohort="+" sudo snap refresh microcloud --cohort="+"
UTILISATION
Use the lxc command to manage containers and VMs (QEMU). MicroCloud handles the software-defined infrastructure (network and storage) transparently. See the LXC Cheat Sheet post [Link].
sudo lxc launch ubuntu:22.04 ct1 --storage remote sudo lxc launch ubuntu:22.04 ct2 --storage local sudo lxc launch ubuntu:22.04 vm1 --vm sudo lxc list
Some commands are only relevant in a cluster:
sudo lxc mv ct1 --target micro2 sudo lxc cp ct1 --target micro3 ct1-copy
System Containers can be migrated live, with no interruption.
To remove a node from the cluster for maintenance or shutdown:
lxc cluster evacuate micro3 lxc cluster restore micro3
To permanently remove a node from the cluster:
lxc cluster remove micro3 lxc cluster remove --force micro3
To add a new node:
sudo microcloud add
BONUS
For a more cutting-edge experience, you may want to try the next release candidate (with KVM):
sudo apt update sudo apt install qemu-kvm ovmf -y kvm-ok && sudo reboot
sudo snap refresh lxd --channel=latest/edge sudo snap install microceph --channel=latest/edge sudo snap install microovn --channel=22.03/edge sudo snap install microcloud --channel=latest/edge sudo snap set lxd ui.enable=true sudo snap set lxd criu.enable=true sudo systemctl reload snap.lxd.daemon.service
sudo microcloud init
watch 'clear ; sudo microcloud cluster list ; sudo lxc cluster list ; sudo microceph cluster list ; sudo microovn cluster list ; sudo lxc list ; sudo lxc storage list ; sudo lxc network list'
Note: By April 2024, Canonical planned to release MicroCloud 2.0 alongside Ubuntu 24.04 LTS on its 20th anniversary. If that has already happened, some of the commands above may be outdated.