7.2 Managing Rocks

One of Rocks' strengths is the web-based management tools it provides. Initially, these are available only from within the clusters since the default firewall configuration blocks HTTP connections to the frontend's public interface. If you want to allow external access, you'll need to change the firewall configuration. To allow access over the public interface, edit the file /etc/sysconfig/iptables and uncomment the line:

-A INPUT -i eth1 -p tcp -m tcp --dport www -j ACCEPT

Then restart the iptables service.

[root@frontend sysconfig]# service iptables restart

Some pages, for security reasons, will still be unreachable.

To view the management page locally, log onto the frontend, start the X Window System, start your browser, and go to http://localhost. You should get a screen that looks something like Figure 7-1.

Figure 7-1. Rocks' web interface

The links on the page will vary depending on the software or rolls you chose to install. For example, if you didn't install PBS, you won't see a link to the PBS Job Queue. Here is a brief description of the links shown on this page.

Cluster Database (SSL)

Rocks maintains a MySQL database for the server. The database is used to generate service-specific configuration files such as /etc/hosts and /etc/dhcpd.conf. This phpMyAdmin web interface to the database can be accessed through the first link. This page will not be accessible over the public interface even if you've changed the firewall. Figure 7-2 shows the first screen into the database. You can follow the links on the left side of the page to view information about the cluster.

Figure 7-2. Rocks database page

Cluster Status (Ganglia)

This link provides a way into Ganglia's home page. Ganglia, a cluster monitoring package, is described in Chapter 10.

Cluster Top (Process Viewer)

This link takes you to a page that displays the top processes running on the cluster. This is basically the Unix top command, but provides cluster-wide information. The columns are similar to those provided by top except for the first two. The first, TN, gives the age of the information in seconds, and the second, HOST, is the host name for the cluster node that the process is running on. You can look at the top(1) manpage for information on how to interpret this page. Figure 7-3 shows the Cluster Top screen for an idle cluster.

PBS Job Queue

PBS is described in Chapter 11. You should see the PBS link only if you've installed the PBS roll.

News (RSS)

This is an alert system that sends RSS-style news items for events within the cluster. It is documented in the Rocks Reference Guide.

Figure 7-3. Cluster Top

Proc filesystem

This link takes you into the /proc subdirectory. The files in this subdirectory contain dynamic information about the state of the operating system. You can examine files to see the current configuration, and, in some cases, change the file to alter the configuration. This page is accessible only on a local system.

Cluster Distribution

The Cluster Distribution link is a link into the /home/install directory on the frontend. This directory holds the RPM packages used to construct the cluster. This page is accessible only on a local system.

Kickstart Graph

This link provides a graphical representation of the information used to create the Kickstart file. This is generated on the fly. Different display sizes are available.

Roll Call

This link returns a page that lists the various rolls that have been installed on your cluster.

Rocks User's Guide/Reference Guide

These are online versions of the Rocks documentation that have been alluded to so often in this chapter.

Make Labels

This link generates a PDF document containing labels for each node in the cluster. The labels contain the cluster name, node name, MAC address, and the Rocks logo. If your cluster name is too long, the logo will obscure it. You should be able to print the document on a standard sheet of labels such as Avery 5260 stock.

Register Your Cluster

This will take you to the Rocks registration site, so you can add your cluster to the list of other Rocks clusters.

Finally, there is a link to the Rocks home page.