Introduction
There are a number of internal URLs MAAS uses during commissioning and deployment which are useful to access when debugging. This document describes what they are and how to access them.
Static files
All bootloaders, images, kernels, and initrds found in /var/lib/maas/boot-resources/current on the rack controller are available over both HTTP and TFTP. Directory listing is enabled over HTTP
http://$RACK:5248/images/
tftp://$RACK/
Bootloader configuration files
All bootloader configuration files are available over TFTP and are generated dynamically by the rack controller. The default configuration is used during enlistment. For any other state the MAC address must be included in the request.
PXELinux i386, AMD64
tftp://$RACK/pxelinux.cfg/default
http://$RACK:5248/pxelinux.cfg/default
# MAC is delaminated with a '-' e.g 52-54-00-20-b1-01
tftp://$RACK/pxelinux.cfg/01-$MAC
http://$RACK:5248/pxelinux.cfg/01-$MAC
GRUB UEFI AMD64, ARM64
tftp://$RACK/grub/grub.cfg-default-amd64
http://$RACK:5248/grub/grub.cfg-default-amd64
# MAC is delaminated with a ':' e.g 52:54:00:dd:d1:50
tftp://$RACK/grub/grub.cfg-$MAC
http://$RACK:5248/grub/grub.cfg-$MAC
PowerNV/PPC64EL
tftp://$RACK/ppc64el/pxelinux.cfg/default
http://$RACK:5248/ppc65el/pxelinux.cfg/default
# MAC is delaminated with a '-' e.g 52-54-00-20-b1-01
tftp://$RACK/ppc64el/pxelinux.cfg/01-$MAC
http://$RACK:5248/ppc64el/pxelinux.cfg/01-$MAC
s390x
tftp://$RACK/s390x-dpm.cfg/$LPAR_UUID
http://$RACK:5248/s390x-dpm.cfg/$LPAR_UUID
s390x DPM Partition
There is only one URL for both known and unknown machines. MAAS will automatically detect a known machine by the MAC address used in the connection to MAAS.
tftp://$RACK/s390x_partition/maas
http://$RACK:5248/s390x_partition/maas
Metadata server
MAAS implements a subset of the EC2 metadata service to provide machines with data such as hostname, SSH keys, and user data to be run. Only a subset of data can be accessed anonymously, most data requires OAUTH1 credentials.
Accessing the metadata server
As of MAAS 2.5 each rack controller runs an nginx HTTP proxy service which allows machines to only have to interact with the rack controller.
Metadata directly from the region
http://$REGION:5240/MAAS/metadata/latest/
Metadata through the nginx proxy
http://$RACK:5248/MAAS/metadata/latest
Preseeds
The preseed contains the initial configuration for cloud-init to configure the system. Two URLs are available, one during enlistment and another used by all other environments.
http://$REGION:5240/MAAS/metadata/latest/enlist-preseed/?op=get_enlist_preseed
http://$REGION:5240/MAAS/metadata/latest/by-id/$SYSTEM_ID/?op=get_preseed
Userdata
The userdata contains scripts and other configuration data which is run by cloud-init. MAAS creates userdata by starting with a template and adding additional required data. These templates can be found in
/etc/maas/preseeds/*userdata*
The data is then base64 encoded and returned to the client.
Enlistment userdata
Enlistment userdata can be access anonymously
http://$REGION:5240/MAAS/metadata/enlist/latest/user-data
Userdata for Curtin(deploying)
http://$REGION:5248/MAAS/curtin/latest/user-data
Userdata for all other ephemeral environments
This method requires OAUTH1 credentials
http://$REGION:5240/MAAS/metadata/latest/user-data
Internal SimpleStreams mirror
The MAAS region provides all rack controllers with images by creating a SimpleStream with the images an administrator has selected to be downloaded. Like images.maas.io an index.json is provided however only one product stream is created.
http://$REGION:5240/MAAS/images-stream/streams/v1/index.json
http://$REGION:5240/MAAS/images-stream/streams/v1/maas:v2:download.json
Images can be downloaded by concatenating the images-streams endpoint with the path in the product stream. For example
http://$REGION:5240/MAAS/images-stream/ubuntu/amd64/hwe-18.04/bionic/20200831/squashfs