Setting up Services
From Debian Clusters
There are four essential services for a cluster I'm going to walk through setting up: a mounted file system (NFS), a DHCP server, a domain name server (BIND), and authentication services. I'll set them up first on the services machines as well as the head node and the worker node image I'm creating. This is done before all the worker nodes are imaged; this way the configuration only needs to be done once.
Shared Filesystem
NFS is used to share a filesystem amongst the nodes. This way users' directories can show up on all of the machines without having to copy the files over each time something is changed. It is also going to be used to install shared software one; this way the software only has to be installed and configured once.
Handing out IP Addresses
DHCP is used to hand out IP addresses on the local network. Since my cluster is going to have its own non-routable IP range (192.168.1.X), all of the machines won't be accessible to the outside world. I need an internal DHCP server to assign the IP addresses to the individual machines if I don't want to have to individually set the IP address on every single machine.
Domain Names
DNS - and specifically, we'll use the implementation BIND - is used to hand out domain names to each of the machines. Again, I could set them up individually on every single machine, and then hand out a list to each machine (called /etc/hosts) that contains the name of each machine and which IP address it goes to, but it's much less time consuming and easier to set up the domain names once using DNS and to have all the configuration in one location.
User Authentication
LDAP is used for setting up an authentication service across the nodes. This will allow users to have the same user login and password across all the nodes, and again, allow configuration in one place rather than on each individual machine.
