Chapter 17. Managing Virtual Machines Using xm
The xm application is a robust management tool that allows you to configure your Red Hat Virtualization environment. As a prerequisite to using xm, you must ensure that the xend daemon is running on your system.
The operating parameters that you must modify reside within the xmdomain.cfg file, which is located in the etc/xen directory. Here are the parameters you can enable or disable in the xmdomain.cfg configuration file:
| Item | Description |
|---|---|
|
kernel |
Determines the fully qualified path to the kernel image |
|
ramdisk |
Determines the fully qualified path to initrd for the initial ramdisk |
|
memory |
Determines the amount of RAM (in MB) to allocate for the domain when it starts |
|
name |
Determines the unique name for a domain |
|
root |
Determines the root device for a domain |
|
nic |
Determines the number of network interface cards for a domain (default is 1) |
|
disk |
Determines the arrays of device block stanzas — the three stanzas are: · mode - device access mode · backend-dev - the backend domain that exports to the guest domain · frontend-dev - determines how the device appears in a guest domain |
|
vif |
Determines arrays of virtual interface stanzas (each stanza represents a set of name=value operations). |
|
builder |
Determines the builder that constructs the domain (default is linux) |
|
cpu |
Determines the CPU count for the domain to start on. 0 indicates the first CPU, 1 the second, etc. (default is -1) |
|
cpus |
Determines which CPUs the domain's VCPU are executable |
|
extra |
Determines the additional information to append to end of the kernel parameter line |
|
nfs_server |
Determines the NFS server IP address to use for the root device |
|
nfs_root |
Determines the root directory as a fully qualified path for the NFS server |
|
vcpus |
Determines the number of virtual CPUs to allocate to a domain (default is 1) |
|
on_shutdown |
Determines the domain shutdown parameter to trigger a graceful shutdown (or xm shutdown) from inside DomU |
|
on_reboot |
Determines the domain shutdown parameter to trigger a graceful reboot (or an xm reboot) from inside DomU |
|
on_crash |
Determines the domain shutdown parameter that trigger DomU crashes. |
Table 17.1. The xmdomain.cfg Configuration File
A vfb is a virtual frame buffer that is defined as a 'stanza'. The stanza represents a set of name = value options, which when integrated into the xmdomain.cfg.5 file, must be separated by commas. The vfb entry in your configuration file resembles:
vfb = [ "stanza" ] "name1=value1, name2=value2, "
You can further configure your vfb environment by the incorporating the options shown in Table 16.2:
| Item | Description |
|---|---|
|
type |
The vnc type option initiates a VNC Server session that connects to an external VNC viewer. The sdl option initiates the internal viewer. |
|
vncdisplay |
Determines the VNC display number to use (defaults to the domain ID value). The VNC server listens on port 5900 + the display number. |
|
vnclisten |
The VNC server's listening address (defaults to 127.0.0.1). |
|
vncunused |
Determines the numerical value and if non-zero, enables the VNC server to listen for the first unused port over 5900. |
|
vncpasswd |
Overrides the default password configured by Xend. |
|
display |
Enables the display for the internal viewer to use (defaults to environment variable DISPLAY). |
|
xauthority |
Enables the authority file for the internal viewer to use (defaults to environment variable XAUTHORITY. |
Table 17.2. The vfb Configuration Options