High Performance Linux Clusters with OSCAR, Rocks, OpenMosix, and MPI [Electronic resources] نسخه متنی

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.