MAAS is only useful once it has images available to provision its nodes. Therefore, one key post-install task is to select and import images from the boot source. Once MAAS imports images, it will update them on an hourly basis, via a default sync mechanism. This page explains how to select and import the images that MAAS requires to provision its nodes.
This article will help you learn:
You can also mirror images locally, build your own custom images, or even work with VMWare images. And there's some background info on images available if you need it.
Canonical provides two SimpleStreams for MAAS images: candidate and stable. Both streams contain Ubuntu images, CentOS images, bootloaders extracted from the Ubuntu archive, and release notifications. Either stream can be used in any version of MAAS greater than 2.1 -- but not all images are supported in older versions.
How to change the stream with the UI
To switch to the candidate stream:
Select Images.
Select Change source.
Select Custom.
Set the URL to http://images.maas.io/ephemeral-v3/candidate.
Select Connect.
MAAS uses the stable stream by default. To switch back to it, simply repeat the above procedure, but set the URL to maas.io.
How to change the stream with the CLI
To switch to a stream with the CLI, enter the following commands:
BOOT_SOURCE_ID=$(maas $PROFILE boot-sources read | jq '.[] | select(.url | contains("images.maas.io/ephemeral-v3")) | .id')
maas $PROFILE boot-source update $BOOT_SOURCE_ID url=$STREAM_URL
How to import standard images from maas.io
The Images page shows what images and architectures have been selected and downloaded. By default, MAAS will automatically grab the most recent Ubuntu LTS releases (and amd64 architecture).
You can tell MAAS to sync images hourly, at the region level, using a toggle switch in the top-right corner of the screen. See Boot image sources) for more details. We highly recommended syncing images hourly. Syncing at the rack controller level (from regiond) occurs every 5 min and cannot be disabled.
To remove an image, simply un-select it and click Save selection.
How to use other image mirrors to download images
You can also host Ubuntu images on a mirror. To use these mirrors:
Select Images.
Select Change source.
Select Custom.
Enter the mirror URL.
Select Connect to bring the mirror online.
Advanced options, such as using a GPG key or keyring to validate the mirror path (snap installation location: /snap/maas/current/usr/share/keyrings/ubuntu-cloudimage-keyring.gpg), are revealed by Selecting Show advanced options.
Optionally, a local mirror can be set up as the boot source. MAAS will then use it instead of the standard internet-based server. Local mirroring significantly reduces the time required import images. See Local image mirror for instructions.
How to import and provision non-Ubuntu images
It is also possible to import and provision images other than Ubuntu. Images supported and provided by MAAS will appear in Images >> Other Images. These images can be imported and used just like the Ubuntu images above.