MAAS and external dhcp setup

[alex barchiesi]

I report here a quick exchange with a user that is setting up a MAAS infrastructure so that it could be useful to anyone with the same issue.

>Hello,

>My name is David García, and we met each other at the TNC18, last  

>week. I have two question about how to deploy Openstack with Juju and  

>Maas.

>1- How should I proceed if I have an already existing external DHCP  

>server in my network?

You could use an external dhcp with MAAS

see here: https://docs.maas.io/2.1/en/installconfig-network-dhcp for more details, 

or (better) you can separate the networks with a different VLAN and setup MAAS dhcp on a VLAN that is not served by your external dhcp (remember to setup the boot network of the machines that you wish to serve)

>2- How can I manage with the same MAAS nodes connected to different  regions? 

>I remember that you show me many machines of different  regions, 

>but as I can understand, the Maas is not directly connected  to all of them, right?

premise: MAAS has a hierarchy with a region (master) node and several cluster (local-region) nodes that provide the DHCP and PXE part.

see slide N 61 of https://docs.google.com/presentation/d/1bb4SAICVQdz_tKdSlssd-VuXbyVqBJP_cP0XFt4VdQ0/edit?usp=sharing

for some details. 

You basically have 2 options:

1. you setup a cluster controller node in each region (this is what we did)

2. or (since you mentioned an external dhcp) you setup a dhcp relay in each region so that they will provide the address to the node (please note that the PXE traffic is possible over lan, but this may render the installation process slower, and you will need to have a shared network that should be present on each of your nodes and the MAAS region controller so that they can see each other). Also this is not completely supported and you will loose the management capability of MAAS itself (e.g. notifications that leases should be removed when a node is returned to the pool). You may also have problems if you setup the HA see here for more details: https://docs.maas.io/2.1/en/manage-ha

 

>Thanks

>David García

may you need more information please keep the thread open

best Alex Barchiesi