Article Sidebar 1 Sidebar 2 sep2005.tar

Of Mice and Keyboards

Today, we have a variety of remote access methods for full, GUI control of a remote device (both with software and hardware solutions). However, for these to be useful, some fundamental things must be working:

  • The network cable must be properly connected.
  • The network interface must be properly configured.
  • The OS must be running properly.
  • The remote access software must be correctly configured and enabled.

If you take away any of those components, it's time to travel to the "local" keyboard or mouse, unless you have remote serial console access available. Even if you have full GUI control, remote serial access can be a good safety net to save you time when trying to restore the GUI access. (And, if you have a serial console service implemented, you may have already noticed an alarm about the disconnected cable. SNMP could have told you that the host isn't answering, but a serial console can tell you whether the device is on and whether the IP settings are correct.)

Let's think outside the server room. With a standard KVM (keyboard/video/mouse) switch, you have some fairly strict length limitations on the cables. These switches also mean that only one machine can be actively monitored at a time, because there is only a single screen and keyboard. (The basic cost-per-port for a basic KVM is also only 20-30 dollars less than for a basic remote serial port.)

Do you have servers located in an external data center? Although there are ways to remotely manage a screen image across the Internet, the price-per-port quickly exceeds 2.5x that of a remote serial port.

In some cases, you need a KVM to get things started. With many Linux and Unix servers and desktop machines, you may need to do the initial configuration using a "local" keyboard and mouse console. After that, you can set up a JumpStart service or make a disk-image installation CD, which will minimize the need for a local screen, and automatically configure the devices to use a serial port for their consoles.

Windows operating systems don't readily allow management via a serial port. However, for the past few years, most BIOS makers have been adding an option to redirect the Power-On Self Test information to a serial port. (There are also efforts being made for managing via Ethernet, with Intel's IPMI spec being a good example: 

http://www.intel.com/design/servers/ipmi/spec.htm