Deploy Nodes

Once a node has been commissioned (see Commission nodes) the next logical step is to deploy it.

Deploying a node means, effectively, to install an operating system on it. The deployed node will also be ready to accept connections via SSH to the 'ubuntu' user account providing an SSH key has been imported to the MAAS user account. This is explained in SSH keys.

To deploy, the underlying machine needs to be configured to netboot (this should already have been done during the commissioning stage). Such a machine will undergo the following process:

  1. DHCP server is contacted
  2. kernel and initrd are received over TFTP
  3. machine boots
  4. initrd mounts a Squashfs image ephemerally over iSCSI
  5. cloud-init triggers deployment process
    1. curtin installation script is run
    2. Squashfs image (same as above) is placed on disk

Note: The curtin installer uses an image-based method and is now the only installer used by MAAS. The older debian-installer (preseed) method has been removed. Some remnants of preseed may still be found however. See /etc/maas/preseed directory.

The agent that triggers deployment varies depending on how the nodes are intended to be used in the long term. For instance, if the nodes are destined to be running complex, inter-related services that may involve scaling up or down, that is, if they will be regarded as a "cloud" resource, then Juju is the recommended deploy agent (it will also install & configure services on the deployed nodes). If you simply want to use MAAS to install a base operating system and work on the machines manually then you can deploy a node directly with the web UI.

Before deploying you should:

  • review and possibly set the HWE kernels and the Kernel boot options that will get used by deployed nodes.
  • ensure any pertinent SSH keys are imported (see SSH keys) to MAAS so connections can be made to deployed nodes.

To deploy directly from MAAS simply select any given node and press the 'Deploy' button.

deploy

You then have the option of deviating from the default OS, release, and kernel. When ready, press 'Go'.

deploy go

While a node is deploying its status will change to Deploying.

Once a node has finished deploying its status will change to Deployed. The node now has an operating system installed and will accept SSH public key authentication requests to the 'ubuntu' account.