Condor and DRBL Bruno Gonçalves & Stefan Boettcher Emory University

Condor Week 2006 Motivation  Maximize computing power while minimizing costs  Optimize the use of the resources that are already available  Maximize resource availability  Permit peaceful coexistence with previously existing Operating Systems

Condor Week 2006 Software  Fedora Core Linux  Other distributions can be used as well  Diskless Remote Book on Linux (DRBL)  Condor clustering softweare

Condor Week 2006 Hardware  Server (complete machine)  Large HDD  Several network cards  Client (stripped down machine)  CPU  RAM  Network Card

Condor Week 2006 DRBL  Uses PXE or Etherboot to let clients boot through the network  All files can be located at the server and accessed via NFS (clients don’t need harddrives!)  Server only provides file sharing and user authentication, all software uses the clients own resources to run

Condor Week 2006 DRBL Installation (I) # drblsrv -i  Updates the system (similarly to “up2date”, etc…)  Makes sure relevant services (dhcpd, NFS, NIS, tftpboot, etc..) are installed  Configures necessary services  Selects the kernel to be used by clients

Condor Week 2006 DRBL Installation II # drblpush -i  Which network interfaces to use  Client booting options (text/gui)  How many clients and hostnames  MAC address to IP/hostname binding (if any)  “Pushes” all the configurations to the clients (creating new clients if necessary)  Needs to be run anytime we want to change the structure of the cluster

Condor Week 2006 Structure Internet DRBL server/Firewall Central Manager Compute nodes x x

Condor Week 2006 Condor Installation #./condor_install  All machines share the same password files  All filesystems are NFS mounted and shared between all the machines  Configure condor for all DRBL clients even nonexistent ones.

Condor Week 2006 Dedicated Cluster  Number of configured clients can be larger than number of machines (easily add more machines)  Clients boot to text mode  Condor configured for dedicated resources

Condor Week 2006 Windows Computer Lab  Number of nodes should correspond to number of machines  MAC address binding can be used for extra security  Nodes can PXEBoot when they’re available for computation (evening / holidays / vacations) and go back to windows when strictly necessary (morning)  Condor’s checkpointing (and flocking) utilities allow for jobs to be ran in whichever resources are available at a given time

Condor Week 2006 Centralized Cluster management  drbl-doit  Run command on all clients  drbl-cp-host, drbl-rm-host  cp/rm file or directory to all clients  drbl-useradd, drbl-userdel  add/del user accounts  drbl-client-service  Control services on clients (drbl-client-service condor start)

Condor Week 2006 Advantages  Flexible  Easily add and remove machines (plug and play)  Usable for both dedicated and opportunistic clustering  Stable  Running for months without problems even with nodes being added, removed and upgraded  Both clients and server can be rebooted without (too much) harm  Efficient  “Biggest bang for your buck”

Condor Week 2006 Disadvantages  Not ideal for IO intensive applications (NFS overhead)  Communication between nodes on different subnets are routed through server  All communication with outside world has to go through server

The End Questions? Suggestions?