Chapter 21. xm quick reference
The xm command is used to manage your Red Hat Virtualization environment using a CLI interface. Most operations can be performed by the
virt-manager
application, including a CLI which is part of
virt-manager
. However, there are a few operations which currently can not be performed using
virt-manager
. As the xm command is part of the Xen environment a few options available with the xm command will not work in a Red Hat Enterprise Linux 5 environment. The list below provides an overview of command options available (and unavailable) in a Red Hat Enterprise Linux 5 environment. As an alternative to using the xm command one can also use the virsh command which is provided as part of the Red Hat Virtualization. The virsh command is layered on top of the libvirt API which can provide a number of benefits over using the xm command. Namely the ability to use virsh in scripts and the ability to manage other hypervisors as they are integrated into the libvirt API.
Warning
It is advised to use virsh or virt-manager instead of xm. The xm command does not handle error checking or configuration file errors very well and mistakes can lead to system instability or errors in virtual machines. Editing Xen configuration files manually is dangerous and should be avoided. Use this chapter at your own risk.
The following are basic and commonly used xm commands:
-
xm help [--long]: view available options and help text.
-
use the xm list command to list active domains:
$ xm list
Name ID Mem(MiB) VCPUs State Time(s)
Domain-0 0 520 2 r----- 1275.5
r5b2-mySQL01 13 500 1 -b---- 16.1
-
xm create [-c]
DomainName/ID
: start a virtual machine. If the -c option is used, the start up process will attach to the guest's console.
-
xm console
DomainName/ID
: attach to a virtual machine's console.
-
xm destroy
DomainName/ID
: terminate a virtual machine , similar to a power off.
-
xm reboot
DomainName/ID
: reboot a virtual machine, runs through the normal system shut down and start up process.
-
xm shutdown
DomainName/ID
: shut down a virtual machine, runs a normal system shut down procedure.
-
xm pause
-
xm unpause
-
xm save
-
xm restore
-
xm migrate
Use the following xm commands to manage resources:
-
xm mem-set
-
use the xm vcpu-list to list virtual CPU assignments/placements:
$ xm vcpu-list
Name ID VCPUs CPU State Time(s) CPU Affinity
Domain-0 0 0 0 r-- 708.9 any cpu
Domain-0 0 1 1 -b- 572.1 any cpu
r5b2-mySQL01 13 0 1 -b- 16.1 any cpu
-
xm vcpu-pin
-
xm vcpu-set
-
use the xm sched-credit command to display scheduler parameters for a given domain:
$ xm sched-credit -d 0
{'cap': 0, 'weight': 256}
$ xm sched-credit -d 13
{'cap': 25, 'weight': 256}
Use the following xm commands for monitoring and troubleshooting:
The xm vnet-list is currently unsupported.
