Remote Serial Port Access with a Virtual Serial Port Proxy

The VMware vSphere™ API supports the use of virtual serial ports on virtual machines that run on ESX™ hosts. A virtual serial port represents a serial port on a virtual machine. A virtual serial port can operate as a network serial port by using a network socket on the host to provide access to remote systems. A remote system is any system on the network that supports a serial port connection with a virtual machine. This feature supports remote console login for system management using an out-of-band connection that bypasses the vSphere Client.

You can also use a virtual serial port for communication through a software pipe, for output to a file, and for communication through a physical serial port on the host. For information about the vSphere API support for these applications, see the description of the VirtualSerialPort object in the vSphere API Reference.

In a VMware® datacenter, a vCenter Server uses vMotion™ to move virtual machines across hosts as part of resource management. vSphere does not support vMotion operations on a virtual machine that has a direct network serial port connection with a remote system. Network serial ports use the host IP address. If the Server attempts to move a virtual machine with a network serial port connection, the host rejects the vMotion request to maintain the connection.

To support vMotion for virtual machines that use network serial ports, you can develop a proxy that operates between a virtual machine and a remote system. The vSphere API supports the use of a third-party virtual serial port concentrator in the datacenter environment. A virtual serial port concentrator acts as a proxy or an access server between virtual machines and remote systems. The proxy maintains communication with virtual machines that are using network serial ports. When a vMotion event occurs, the virtual machine connects to the proxy from its new host so that the connection with the remote system persists.

Virtual machines use the telnet protocol for virtual serial port proxy connections. VMware defines a telnet extension that includes commands for proxy notification of vMotion events.

This chapter provides the following information:

■	Virtual Serial Port Proxy Capabilities

■	Network Serial Ports

■	VMware Telnet Session

■	vMotion and Persistent Serial Port Connections

See VMware Telnet Extension Commands for Proxy Communication for reference information about the VMware telnet extension commands.