Local Image Mirror

Images are delivered to MAAS via the SimpleStreams protocol and the mirroring of these images is worthy of consideration. This option is especially useful when your environment has a slow or unreliable Internet link. In such cases, when the images are requested they will be instantly available and the disadvantaged link will be less readily apparent.

Begin by installing the necessary software on the host that will house the mirror:

sudo apt install simplestreams

First define some variables to unclutter eventual CLI commands:

KEYRING_FILE=/usr/share/keyrings/ubuntu-cloudimage-keyring.gpg
IMAGE_SRC=https://images.maas.io/ephemeral-v3/daily/
IMAGE_DIR=/var/www/html/maas/images/ephemeral-v3/daily

Note: The v3 format offers only a 'daily' stream whereas in previous versions a 'releases' stream was available. The latter changes far less frequently but lacks security and bug fixes.

The below example selects all available kernels that are compatible with either Ubuntu 14.04 (Trusty) and Ubuntu 16.04 (Xenial) for the amd64 architecture, resulting in a download of approximately 3.1 GB. The second command mirrors the bootloaders.

sudo sstream-mirror --keyring=$KEYRING_FILE $IMAGE_SRC $IMAGE_DIR \
    'arch=amd64' 'release~(trusty|xenial)' --max=1 --progress
sudo sstream-mirror --keyring=$KEYRING_FILE $IMAGE_SRC $IMAGE_DIR \
    'os~(grub*|pxelinux)' --max=1 --progress

To know in advance what the sstream-mirror command will grab and/or if you want to save bandwidth and time due to possible mis-selections, include the --dry-run option. When you are satisfied, remove that option to initiate the download.

The images will be written to disk in the directory defined by the variable 'IMAGE_DIR' above and the 'location' of the new boot source will be:

URL=http://<myserver>/maas/images/ephemeral-v3/daily/

Where <myserver> identifies your server's hostname or IP address.

Verify the availability of the images by visiting the above URL.

The final sstream-mirror command should be invoked at regular intervals (i.e. with cron) to ensure the mirror contains the latest images.

Configure MAAS to use the local mirror

To point MAAS to the local image server (mirror) using the web UI navigate to the Settings tab and scroll down to the 'Boot Images' section. Then fill in the fields 'Sync URL' and 'Keyring Path' using the values, respectively, for variables 'URL' and 'KEYRING_FILE' from above.

See CLI Image Management for instructions on how to do this with the CLI.