This section explains how to reconfigure a cluster after the initial installation, when some of the cluster wide configurations need to be changed (e.g. public IP, FQDN of the frontend, etc.). The reconfiguration process generates a script which performs all the necessary steps to modify the desired parameters. The script is generated traversing the graph and parsing the section marked as "reconfigure" section (see the developers guide).
Reconfiguring a cluster is a potentially harmful operation and can damage you system. The safest option is always reinstalling the frontend with the correct values.
Currently only the following roll support reconfiguration:
The attribute which can be reconfigure are:
The attribute names are self explanatory and they can be used to change public network configuration and private network configuration.
The reconfiguration works only if you haven't changed manually rocks default configurations (Postfix, Named, Apache, configuration files should still be at their default configurations)
To change one of the main parameters of your system first reset the history of your attributes change:
# rocks run reconfigure clear=1
To change the attributes, use the standard rocks commands (in the following example we show how to change the public ip address):
# rocks set attr Kickstart_PublicAddress 126.96.36.199 # rocks set attr Kickstart_PublicNetmask 255.255.255.0 # rocks set attr Kickstart_PublicGateway 188.8.131.52 # rocks set attr Kickstart_PublicHostname newhostname.somedomain.com
When you change an attribute (e.g. Kickstart_PublicAddress) the old value will be stored in an attribute named with a "_old" postfix (e.g. Kickstart_PublicAddress_old). You can verify which attributes will be updated with reconfigure using showattr:
# rocks run reconfigure showattr=1 User modified attributes ATTR OLD VALUE -> NEW VALUE Kickstart_PublicNetmask 255.255.255.0 255.255.255.0 Kickstart_PublicHostname myoldhost.ucsd.edu newhostname.somedomain.com Kickstart_PublicAddress 184.108.40.206 220.127.116.11 Kickstart_PublicGateway 18.104.22.168 22.214.171.124 Additional attributes Kickstart_PrivateHostname myoldhost newhostname Kickstart_PublicBroadcast 126.96.36.199 188.8.131.52 Kickstart_PublicNetwork 184.108.40.206 220.127.116.11 Kickstart_PublicDNSDomain ucsd.edu somedomain.com Kickstart_PublicNetmaskCIDR 24 24
The command shows also the attributes that will be updated to maintain consistency (section "Additional attributes") in the rocks database. If all the modified values make sense you can proceed and run the reconfigure script:
# rocks run reconfigure > /tmp/script.sh # # inspect the script.sh # bash /tmp/script.sh
Depending on what attributes you have changed you will need to reinstall all your nodes.
# rocks run host compute login "/boot/kickstart/cluster-kickstart-pxe"
If you have SGE installed the reconfigure operation will wipe all your SGE configurations (queue configuration, host configuration, etc.)
If you change some private networking parameters you will have to remove and re-install all your nodes with insert-ether. For example if you change the private network address (e.g. from 10.1.0.0 to 10.5.0.0) all the IP addresses of your node will be out of the new network. For this reason you will need to remove all the compute nodes and re-add them with insert-ethernet.