Chapter 10. Managing guests with xend

Chapter 10. Managing guests with `xend`

The xend node control daemon performs certain system management functions that relate to virtual machines. This daemon controls the virtualized resources, and xend must be running to interact with virtual machines. Before you start xend, you must specify the operating parameters by editing the xend configuration file /etc/xen/xend-config.sxp. Here are the parameters you can enable or disable in the xend-config.sxp configuration file:

Item	Description
(console-limit)	Determines the console server's memory buffer limit xend_unix_server and assigns values on a per domain basis.
(min-mem)	Determines the minimum number of megabytes that is reserved for domain0 (if you enter 0, the value does not change).
(dom0-cpus)	Determines the number of CPUs in use by domain0 (at least 1 CPU is assigned by default).
(enable-dump)	Determines that a crash occurs then enables a dump (the default is 0).
(external-migration-tool)	Determines the script or application that handles external device migration. Scripts must reside in `etc/xen/scripts/external-device-migrate`.
(logfile)	Determines the location of the log file (default is `/var/log/xend.log`).
(loglevel)	Filters out the log mode values: DEBUG, INFO, WARNING, ERROR, or CRITICAL (default is DEBUG).
(network-script)	Determines the script that enables the networking environment (scripts must reside in `etc/xen/scripts` directory).
(xend-http-server)	Enables the http stream packet management server (the default is no).
(xend-unix-server)	Enables the unix domain socket server, which is a socket server is a communications endpoint that handles low level network connections and accepts or rejects incoming connections. The default value is set to yes.
(xend-relocation-server)	Enables the relocation server for cross-machine migrations (the default is no).
(xend-unix-path)	Determines the location where the `xend-unix-server` command outputs data (default is `var/lib/xend/xend-socket`)
(xend-port)	Determines the port that the http management server uses (the default is 8000).
(xend-relocation-port)	Determines the port that the relocation server uses (the default is 8002).
(xend-relocation-address)	Determines the host addresses allowed for migration. The default value is the value of `xend-address`.
(xend-address)	Determines the address that the domain socket server binds to. The default value allows all connections.

Table 10.1. xend configuration parameters

After setting these operating parameters, you should verify that xend is running and if not, initialize the daemon. At the command prompt, you can start the xend daemon by entering the following:

service xend start

You can use xend to stop the daemon:

service xend stop

This stops the daemon from running.

You can use xend to restart the daemon:

service xend restart

The daemon starts once again.

You check the status of the xend daemon.

service xend status

The output displays the daemon's status.

Enabling `xend` at boot time

Use the chkconfig command to add the xend to the initscript.

chkconfig --level 345 xend

The the xend will now start at runlevels 3, 4 and 5.