System News
"Using ctelnet in Sun Cluster Software with Secure Shell"
Tech Tip Offers Alternative Method to telnet
September 27, 2004,
Volume 79, Issue 5

...although "ctelnet is usually used to connect to identically configured systems in a cluster," it is not required in this situation.

A tech tip from Vlad Grama describes how developers can use the ctelnet application in SunTM Cluster software to connect to systems by using the ssh command. Grama notes that by using this method, users are offered flexibility from the telnet command.

In his description of this technique, Grama identifies ctelnet as part of the Sun Cluster Console or SUNWccon package that is available in the Sun HPC ClusterToolsTM software. As a GUI, the ctelnet application is primarily used to run interactive commands simultaneously on systems with identical software configurations. Since ctelnet utilizes telnet by default for communication, Grama recognizes that this could disadvantage some environments and he lists the drawbacks along with a brief explanation of each.

Grama points out that it is not necessary to have a cluster configured to use this method, explaining that although "ctelnet is usually used to connect to identically configured systems in a cluster," it is not required in this situation. "You can connect to any group of systems," he writes.

He outlines the requirements necessary including the SUNWccon package and the ability to run a Secure Shell server. The tested configuration he references in this article includes the client system, SolarisTM 9 Operating System (Solaris OS) (SPARCR Platform Edition) and the Sun Cluster Console package from the Sun Cluster 3.0 distribution; and the controlled systems, Solaris 9 OS (SPARC Platform Edition) with SolarisTM Secure Shell server.

This article proceeds by detailing how to set-up ctelnet for default use through the creation of the /etc/clusters text file and the run command. Grama follows with three configuration steps needed to ensure ctelnet is used instead of telnet. He provides an example to assist the reader through the steps.

He concludes by clarifying that the flexibility offered by running ctelnet is that it can either be run as the system's default: "Run the original ctelnet binary, and connections are made using telnet;" or indirectly: "run the myctelnet script, and connections are encrypted, using ssh." In either case, the /etc/clusters configuration file does not require modification.

To read Grama's tech tip in its entirety, visit:

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