MAAS relies on a repository of OS images for machine deployment, called a SimpleStreams source. There are two streams: candidate and stable. The stable stream is fully tested, reliable, and generally considered production-ready. Candidate images are essentially pre-release images – they are newer, so they may have bugs or incomplete testing. Use the stable stream if you’re deploying machines in production, and candidate if you need support for a newer OS version that is not yet stable. MAAS defaults to stable if you do not make a choice.
Both contain either Ubuntu or CentOS, a bootloader, an initial RAMdisk filesystem, and release notifications. MAAS syncs images hourly at the region level. Rack controllers cache files as needed.
Switch image streams
You can switch streams at any time using these procedures:
UI
Images > Change source > Custom > set URL to:
- Stable:
http://images.maas.io/ephemeral-v3/stable - Candidate:
http://images.maas.io/ephemeral-v3/candidate
CLI
BOOT_SOURCE_ID=$(maas $PROFILE boot-sources read)
Manage images
Choose which images to keep locally. Images must be downloaded before they can be deployed.
UI
Main menu > Images > Select/Unselect > Save selection
CLI
maas $PROFILE boot-sources read # list boot sources
maas $PROFILE boot-source-selections create $SOURCE_ID \
os="ubuntu" release="$SERIES" arches="$ARCH" \
subarches="$KERNEL" labels="*" # select boot sources
maas $PROFILE boot-resources read # list images
maas $PROFILE boot-resources import # select images
Additional CLI management commands
Delete a boot source
maas $PROFILE boot-source delete $SOURCE_ID
Update a boot source
maas $PROFILE boot-source update $SOURCE_ID \
url=$URL keyring_filename=$KEYRING_FILE
Add a new boot source
maas $PROFILE boot-sources create \
url=$URL keyring_filename=$KEYRING_FILE
Use /usr/share/keyrings/ubuntu-cloudimage-keyring.gpg as the keyring file if the new source is a mirror of the official streams.
Use a custom mirror
UI
- Images > Change source > Custom > enter URL > Connect.
- For advanced options, select Show advanced options.
- Set up a local mirror (below) for faster imports.
Use a local mirror
A local mirror can improve image sync performance.
Install SimpleStreams
Start by installing SimpleStreams:
sudo apt install simplestreams
Define helper variables
Define these variables for cleaner CLI commands:
KEYRING_FILE=/usr/share/keyrings/ubuntu-cloudimage-keyring.gpg
IMAGE_SRC=https://images.maas.io/ephemeral-v3/stable
IMAGE_DIR=/var/www/html/maas/images/ephemeral-v3/stable
Mirror your kernels
Mirror your kernels with these commands:
sudo sstream-mirror --keyring=$KEYRING_FILE $IMAGE_SRC $IMAGE_DIR 'arch=amd64' 'release~(bionic|focal)' --max=1 --progress
sudo sstream-mirror --keyring=$KEYRING_FILE $IMAGE_SRC $IMAGE_DIR 'os~(grub*|pxelinux)' --max=1 --progress
Use --dry-run to preview your selection.
MAAS saves images to the directory defined by ‘IMAGE_DIR’. The new boot source URL will be http://<myserver>/maas/images/ephemeral-v3/stable/.
Verify image availability at the URL above. Regularly update your mirror with cron to fetch the latest images.
Set URL=https://$MIRROR/maas/images/ephemeral-v3/stable/ and KEYRING_FILE=/usr/share/keyrings/ubuntu-cloudimage-keyring.gpg, where $MIRROR is the mirror server.
Last updated 2 days ago.