First steps with Incus: launching containers and VMs

Read this page in French

Once Incus is installed, everything goes through one coherent CLI: incus launch creates an instance, incus exec runs commands inside it, incus snapshot saves it. This guide walks the essential gestures on real examples: launch a container, launch a virtual machine, get inside, take a snapshot, adjust the configuration, and manage the lifecycle. Everything was tested on Incus 7.0. For anyone discovering Incus after the installation.

What you will learn

• Launch a container and a virtual machine (incus launch).
• Run commands and open a shell (incus exec).
• List and inspect instances (incus list, incus info).
• Take and restore a snapshot.
• Manage the lifecycle (start, stop, delete).

Launching your first container

The key command is incus launch <image> <name>. Images come by default from the images: remote, the official image server.

incus launch images:debian/13 c1

In a few seconds the container starts and gets an address on incusbr0:

incus list

+------+---------+-----------------------+-----------+
| NAME |  STATE  |         IPV4          |   TYPE    |
+------+---------+-----------------------+-----------+
| c1   | RUNNING | 10.173.191.191 (eth0) | CONTAINER |
+------+---------+-----------------------+-----------+

launch against init

incus launch creates and starts the instance. incus init creates it without starting it, which is handy to configure it before its first boot (incus start afterwards).

Getting inside the instance

To run a command inside, use incus exec <name> -- <command>:

incus exec c1 -- cat /etc/os-release
# PRETTY_NAME="Debian GNU/Linux 13 (trixie)"

For an interactive shell, incus shell (or incus exec c1 -- bash):

incus shell c1

That is the whole difference with Docker: an Incus container is a complete system (with systemd, services, users), not a single process. You connect to it like a small machine.

The container has an IP but no internet?

If an instance gets an address on incusbr0 but has neither DNS nor internet access, the culprit is almost always Docker installed on the same host: its daemon forces an iptables FORWARD DROP rule that drops Incus traffic. The workaround (DOCKER-USER rules) is detailed in Incus vs Docker. An over-strict firewall (firewalld or ufw) produces the same symptom.

Inspecting an instance

incus list gives the overview; incus info details one instance (state, type, resources, network):

incus info c1
# Name: c1
# Status: RUNNING
# Type: container
# Architecture: x86_64

To see the images cached locally:

incus image list

Launching a virtual machine

The same launch creates a full virtual machine with the --vm option (QEMU) instead of a container:

incus launch images:ubuntu/24.04 vm1 --vm

+------+---------+-------------------------+-----------------+
| NAME |  STATE  |          IPV4           |      TYPE       |
+------+---------+-------------------------+-----------------+
| vm1  | RUNNING | 10.173.191.248 (enp5s0) | VIRTUAL-MACHINE |
+------+---------+-------------------------+-----------------+

Same commands, two technologies: incus exec vm1 -- ... works in the virtual machine just as in the container, thanks to the built-in agent.

VMs and hardware virtualisation

Incus virtual machines rely on KVM: the host has to expose hardware virtualisation (VT-x or AMD-V). If Incus itself runs inside a virtual machine, enable nested virtualisation on the hypervisor.

Taking a snapshot

Before a risky operation, incus snapshot create freezes the instance state:

incus snapshot create c1 snap0
incus snapshot list c1

+-------+----------------------+------------+----------+
| NAME  |       TAKEN AT       | EXPIRES AT | STATEFUL |
+-------+----------------------+------------+----------+
| snap0 | 2026/06/30 20:59 UTC |            | NO       |
+-------+----------------------+------------+----------+

If something goes wrong, restore with incus snapshot restore c1 snap0. The snapshot captures the disk; add --stateful to also freeze the memory of a running instance.

Adjusting the configuration

Resources are set live with incus config set:

incus config set c1 limits.memory=512MiB
incus config get c1 limits.memory
# 512MiB

You limit CPU the same way (limits.cpu=2), add devices (disk, network card, port forwarding), and enable automatic start (boot.autostart=true).

Managing the lifecycle

incus stop c1            # stop
incus start c1           # start
incus restart c1         # restart
incus delete c1          # delete (a stopped instance)
incus delete c1 --force  # force deletion of a running instance

A deleted instance is gone for good, along with its snapshots: remember to export or back up what matters first.

Key points

• incus launch images:<distro> <name> creates and starts an instance from the images: remote.
• Add --vm for a virtual machine instead of a container; the same commands apply.
• incus exec runs a command, incus shell opens a shell: an Incus container is a complete system.
• incus snapshot create saves the state; restore with snapshot restore.
• incus config set tunes memory, CPU and devices live.

FAQ: common questions about first steps with Incus

How do you launch a container with Incus?

With incus launch followed by the image and a name, for example incus launch images:debian/13 c1. The image comes from the images: remote by default. The container starts in a few seconds and gets an address on the incusbr0 network. You check it with incus list.

What is the difference between incus launch and incus init?

incus launch creates and starts the instance in one command. incus init creates it without starting it, which lets you change its configuration (CPU, memory, devices) before the first boot, then run incus start.

How do you get inside an Incus container?

With incus exec to run a command, for example incus exec c1 -- cat /etc/os-release, or incus shell c1 to open an interactive shell.

How do you launch a virtual machine with Incus?

With the same incus launch command and the --vm option, for example incus launch images:ubuntu/24.04 vm1 --vm. Incus then creates a full QEMU virtual machine instead of a container. The same commands work thanks to the built-in agent. KVM hardware virtualisation is required.

How do you take a snapshot with Incus?

With incus snapshot create followed by the instance name and the snapshot name, for example incus snapshot create c1 snap0. You list them with incus snapshot list and restore with incus snapshot restore c1 snap0. The --stateful option also freezes the memory of a running instance, not just the disk.

Next steps

• Running OCI containers with Incus: run application images from Docker Hub on the server you just took in hand.
• Managing containers and VMs: the image registry, devices and configuration that incus launch does not show.
• Incus networking: make your first instances reachable from somewhere other than the host.

×

📖 Voir la documentation →