xm(1) Xen xm(1)NAMExm - Obsolete xen management user interface
SYNOPSISxm subcommand [args]
DESCRIPTION
This program is now superseded by xl, which should be largely
backwards-compatible with xm.
The xm program is the main interface for managing Xen guest domains
when the obsolete Xend toolstack is in use. The program can be used to
create, pause, and shutdown domains. It can also be used to list
current domains, enable or pin VCPUs, and attach or detach virtual
block devices.
The basic structure of every xm command is almost always:
xm subcommand domain-id [OPTIONS]
Where subcommand is one of the subcommands listed below, domain-id is
the numeric domain id, or the domain name (which will be internally
translated to domain id), and OPTIONS are subcommand specific options.
There are a few exceptions to this rule in the cases where the
subcommand in question acts on all domains, the entire machine, or
directly on the Xen hypervisor. Those exceptions will be clear for
each of those subcommands.
NOTES
All xm operations rely upon the Xen control daemon, aka xend. For any
xm commands to run, xend must also be running. For this reason you
should start xend as a service when your system first boots using Xen.
Most xm commands require root privileges to run due to the
communications channels used to talk to the hypervisor. Running as non
root will return an error.
Most xm commands act synchronously, except maybe create, shutdown, mem-
set and vcpu-set. The fact that the xm command returned doesn't
necessarily mean that the action is complete and you must poll through
xm list periodically to detect that the operation completed.
DOMAIN SUBCOMMANDS
The following subcommands manipulate domains directly. As stated
previously, most commands take domain-id as the first parameter.
console domain-id
Attach to domain domain-id's console. If you've set up your
domains to have a traditional log in console this will look much
like a normal text log in screen.
This uses the back end xenconsole service which currently only
works for para-virtual domains.
The attached console will perform much like a standard serial
console, so running curses based interfaces over the console is not
advised. Vi tends to get very odd when using it over this
interface.
Use the key combination Ctrl+] to detach the domain console.
create configfile [OPTIONS] [vars]..
The create subcommand requires a config file and can optionally
take a series of vars that add to or override variables defined in
the config file. See xmdomain.cfg for full details of that file
format, and possible options used in either the configfile or for
vars.
configfile can either be an absolute path to a file, or a relative
path to a file located in /etc/xen/vm.
Create will return as soon as the domain is started. This does not
mean the guest OS in the domain has actually booted, or is
available for input.
OPTIONS
--help_config
Print the available configuration variables vars. These
variables may be used on the command line or in the
configuration file configfile.
-q, --quiet
No console output.
--path
Search path for configuration scripts. The value of PATH is a
colon-separated directory list.
-f=FILE, --defconfig=FILE
Use the given Python configuration script. The configuration
script is loaded after arguments have been processed. Each
command-line option sets a configuration variable named after
its long option name, and these variables are placed in the
environment of the script before it is loaded. Variables for
options that may be repeated have list values. Other variables
can be set using name=value on the command line. After the
script is loaded, option values that were not set on the
command line are replaced by the values set in the script.
-F=FILE, --config=FILE
Use the given SXP formatted configuration script. SXP is the
underlying configuration format used by Xen. SXP configuration
scripts can be hand-written or generated from Python
configuration scripts, using the -n (dryrun) option to print
the configuration. An SXP formatted configuration file may
also be generated for a given domain-id by redirecting the
output from the the xm list --long domain-id to a file.
-n, --dryrun
Dry run - prints the resulting configuration in SXP but does
not create the domain.
-x, --xmldryrun
XML dry run - prints the resulting configuration in XML but
does not create the domain.
-s, --skipdtd
Skip DTD checking - skips checks on XML before creating.
Experimental. Can decrease create time.
-p, --paused
Leave the domain paused after it is created.
-c, --console_autoconnect
Attach console to the domain as soon as it has started. This
is useful for determining issues with crashing domains.
EXAMPLES
with config file
xm create Fedora4
This creates a domain with the file /etc/xen/vm/Fedora4, and
returns as soon as it is run.
without config file
xm create /dev/null ramdisk=initrd-xen \
kernel=/boot/vmlinuz-xen \
name=ramdisk vif='' vcpus=1 \
memory=64 root=/dev/ram0
This creates the domain without using a config file (more
specifically using /dev/null as an empty config file), kernel
and ramdisk as specified, setting the name of the domain to
"ramdisk", also disabling virtual networking. (This example
comes from the xm-test test suite.)
delete
Remove a domain from Xend domain management. The xm list command
shows the domain names.
destroy domain-id
Immediately terminate the domain domain-id. This doesn't give the
domain OS any chance to react, and is the equivalent of ripping the
power cord out on a physical machine. In most cases you will want
to use the shutdown command instead.
domid domain-name
Converts a domain name to a domain id using xend's internal
mapping.
domname domain-id
Converts a domain id to a domain name using xend's internal
mapping.
dump-core [OPTIONS] domain-id [filename]
Dumps the virtual machine's memory for the specified domain to the
filename specified. The dump file will be written to a
distribution specific directory for dump files. Such as:
/var/lib/xen/dump or /var/xen/dump Defaults to dumping the core
without pausing the domain if no OPTIONS are specified.
OPTIONS
-L, --live
Dump core without pausing the domain.
-C, --crash
Crash domain after dumping core.
help [--long]
Displays the short help message (i.e. common commands).
The --long option prints out the complete set of xm subcommands,
grouped by function.
list [OPTIONS] [domain-id ...]
Prints information about one or more domains. If no domains are
specified it prints out information about all domains.
OPTIONS
-l, --long
The output for xm list is not the table view shown below, but
instead presents the data in SXP format.
--label
Security labels are added to the output of xm list and the
lines are sorted by the labels (ignoring case). See the ACCESS
CONTROL SUBCOMMAND section of this man page for more
information about labels.
--state=<state>
Output information for VMs in the specified state.
EXAMPLE
An example format for the list is as follows:
Name ID Mem(MiB) VCPUs State Time(s)
Domain-0 0 98 1 r----- 5068.6
Fedora3 164 128 1 r----- 7.6
Fedora4 165 128 1 ------ 0.6
Mandrake2006 166 128 1 -b---- 3.6
Mandrake10.2 167 128 1 ------ 2.5
Suse9.2 168 100 1 ------ 1.8
Name is the name of the domain. ID the numeric domain id. Mem is
the desired amount of memory to allocate to the domain (although it
may not be the currently allocated amount). VCPUs is the number of
virtual CPUs allocated to the domain. State is the run state (see
below). Time is the total run time of the domain as accounted for
by Xen.
STATES
The State field lists 6 states for a Xen domain, and which ones the
current domain is in.
r - running
The domain is currently running on a CPU.
b - blocked
The domain is blocked, and not running or runnable. This can
be caused because the domain is waiting on IO (a traditional
wait state) or has gone to sleep because there was nothing else
for it to do.
p - paused
The domain has been paused, usually occurring through the
administrator running xm pause. When in a paused state the
domain will still consume allocated resources like memory, but
will not be eligible for scheduling by the Xen hypervisor.
s - shutdown
The guest has requested to be shutdown, rebooted or suspended,
and the domain is in the process of being destroyed in
response.
c - crashed
The domain has crashed, which is always a violent ending.
Usually this state can only occur if the domain has been
configured not to restart on crash. See xmdomain.cfg for more
info.
d - dying
The domain is in process of dying, but hasn't completely
shutdown or crashed.
NOTES
The Time column is deceptive. Virtual IO (network and block
devices) used by domains requires coordination by Domain0,
which means that Domain0 is actually charged for much of the
time that a DomainU is doing IO. Use of this time value to
determine relative utilizations by domains is thus very
suspect, as a high IO workload may show as less utilized than a
high CPU workload. Consider yourself warned.
mem-max domain-id mem
Specify the maximum amount of memory the domain is able to use.
mem is specified in megabytes.
The mem-max value may not correspond to the actual memory used in
the domain, as it may balloon down its memory to give more back to
the OS.
mem-set domain-id mem
Set the domain's used memory using the balloon driver.
Because this operation requires cooperation from the domain
operating system, there is no guarantee that it will succeed. This
command will definitely not work unless the domain has the required
paravirt driver.
Warning: There is no good way to know in advance how small of a
mem-set will make a domain unstable and cause it to crash. Be very
careful when using this command on running domains.
migrate domain-id host [OPTIONS]
Migrate a domain to another host machine. Xend must be running on
other host machine, it must be running the same version of Xen, it
must have the migration TCP port open and accepting connections
from the source host, and there must be sufficient resources for
the domain to run (memory, disk, etc).
Migration is pretty complicated, and has many security
implications. Please read the Xen User's Guide to ensure you
understand the ramifications and limitations on migration before
attempting it in production.
OPTIONS
-l, --live
Use live migration. This will migrate the domain between hosts
without shutting down the domain. See the Xen User's Guide for
more information.
-r, --resource Mbs
Set maximum Mbs allowed for migrating the domain. This ensures
that the network link is not saturated with migration traffic
while attempting to do other useful work.
new configfile [OPTIONS] [vars]...
Adds a domain to Xend domain management.
The new subcommand requires a config file and can optionally take a
series of vars that add to or override variables defined in the
config file. See xmdomain.cfg for full details of that file
format, and possible options used in either the configfile or for
vars.
configfile can either be an absolute path to a file, or a relative
path to a file located in /etc/xen.
The new subcommand will return without starting the domain. The
domain needs to be started using the xm start command.
OPTIONS
--help_config
Print the available configuration variables vars. These
variables may be used on the command line or in the
configuration file configfile.
-q, --quiet
No console output.
--path
Search path for configuration scripts. The value of PATH is a
colon-separated directory list.
-f=FILE, --defconfig=FILE
Use the given Python configuration script. The configuration
script is loaded after arguments have been processed. Each
command-line option sets a configuration variable named after
its long option name, and these variables are placed in the
environment of the script before it is loaded. Variables for
options that may be repeated have list values. Other variables
can be set using name=value on the command line. After the
script is loaded, option values that were not set on the
command line are replaced by the values set in the script.
-F=FILE, --config=FILE
Use the given SXP formatted configuration script. SXP is the
underlying configuration format used by Xen. SXP configuration
scripts can be hand-written or generated from Python
configuration scripts, using the -n (dryrun) option to print
the configuration. An SXP formatted configuration file may
also be generated for a given domain-id by redirecting the
output from the the xm list --long domain-id to a file.
-n, --dryrun
Dry run - prints the resulting configuration in SXP but does
not create the domain.
-x, --xmldryrun
XML dry run - prints the resulting configuration in XML but
does not create the domain.
-s, --skipdtd
Skip DTD checking - skips checks on XML before creating.
Experimental. Can decrease create time.
-p, --paused
Leave the domain paused after it is created.
-c, --console_autoconnect
Attach console to the domain as soon as it has started. This
is useful for determining issues with crashing domains.
pause domain-id
Pause a domain. When in a paused state the domain will still
consume allocated resources such as memory, but will not be
eligible for scheduling by the Xen hypervisor.
reboot [OPTIONS] domain-id
Reboot a domain. This acts just as if the domain had the reboot
command run from the console. The command returns as soon as it
has executed the reboot action, which may be significantly before
the domain actually reboots.
The behavior of what happens to a domain when it reboots is set by
the on_reboot parameter of the xmdomain.cfg file when the domain
was created.
OPTIONS
-a, --all
Reboot all domains.
-w, --wait
Wait for reboot to complete before returning. This may take a
while, as all services in the domain will have to be shut down
cleanly.
restore state-file
Build a domain from an xm save state file. See save for more info.
resume domain-name [OPTIONS]
Moves a domain out of the suspended state and back into memory.
OPTIONS
-p, <--paused>
Moves a domain back into memory but leaves the domain in a
paused state. The xm unpause subcommand may then be used to
bring it out of the paused state.
save domain-id state-file
Saves a running domain to a state file so that it can be restored
later. Once saved, the domain will no longer be running on the
system, thus the memory allocated for the domain will be free for
other domains to use. xm restore restores from this state file.
This is roughly equivalent to doing a hibernate on a running
computer, with all the same limitations. Open network connections
may be severed upon restore, as TCP timeouts may have expired.
shutdown [OPTIONS] domain-id
Gracefully shuts down a domain. This coordinates with the domain
OS to perform graceful shutdown, so there is no guarantee that it
will succeed, and may take a variable length of time depending on
what services must be shutdown in the domain. The command returns
immediately after signally the domain unless that -w flag is used.
The behavior of what happens to a domain when it reboots is set by
the on_shutdown parameter of the xmdomain.cfg file when the domain
was created.
OPTIONS
-a Shutdown all domains. Often used when doing a complete
shutdown of a Xen system.
-w Wait for the domain to complete shutdown before returning.
start domain-name [OPTIONS]
Start a Xend managed domain that was added using the xm new
command.
OPTIONS
-p, --paused
Do not unpause domain after starting it.
-c, --console_autoconnect
Connect to the console after the domain is created.
suspend domain-name
Suspend a domain to a state file so that it can be later resumed
using the xm resume subcommand. Similar to the xm save subcommand
although the state file may not be specified.
sysrq domain-id letter
Send a Magic System Request signal to the domain. For more
information on available magic sys req operations, see sysrq.txt in
your Linux Kernel sources.
unpause domain-id
Moves a domain out of the paused state. This will allow a
previously paused domain to now be eligible for scheduling by the
Xen hypervisor.
vcpu-set domain-id vcpu-count
Enables the vcpu-count virtual CPUs for the domain in question.
Like mem-set, this command can only allocate up to the maximum
virtual CPU count configured at boot for the domain.
If the vcpu-count is smaller than the current number of active
VCPUs, the highest number VCPUs will be hotplug removed. This may
be important for pinning purposes.
Attempting to set the VCPUs to a number larger than the initially
configured VCPU count is an error. Trying to set VCPUs to < 1 will
be quietly ignored.
Because this operation requires cooperation from the domain
operating system, there is no guarantee that it will succeed. This
command will not work with a full virt domain.
vcpu-list [domain-id]
Lists VCPU information for a specific domain. If no domain is
specified, VCPU information for all domains will be provided.
vcpu-pin domain-id vcpu cpus
Pins the the VCPU to only run on the specific CPUs. The keyword
all can be used to apply the cpus list to all VCPUs in the domain.
Normally VCPUs can float between available CPUs whenever Xen deems
a different run state is appropriate. Pinning can be used to
restrict this, by ensuring certain VCPUs can only run on certain
physical CPUs.
XEN HOST SUBCOMMANDS
dmesg [-c]
Reads the Xen message buffer, similar to dmesg on a Linux system.
The buffer contains informational, warning, and error messages
created during Xen's boot process. If you are having problems with
Xen, this is one of the first places to look as part of problem
determination.
OPTIONS
-c, --clear
Clears Xen's message buffer.
info
Print information about the Xen host in name : value format. When
reporting a Xen bug, please provide this information as part of the
bug report.
Sample output looks as follows (lines wrapped manually to make the
man page more readable):
host : talon
release : 2.6.12.6-xen0
version : #1 Mon Nov 14 14:26:26 EST 2005
machine : i686
nr_cpus : 2
nr_nodes : 1
cores_per_socket : 1
threads_per_core : 1
cpu_mhz : 696
hw_caps : 0383fbff:00000000:00000000:00000040
total_memory : 767
free_memory : 37
xen_major : 3
xen_minor : 0
xen_extra : -devel
xen_caps : xen-3.0-x86_32
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xfc000000
xen_changeset : Mon Nov 14 18:13:38 2005 +0100
7793:090e44133d40
cc_compiler : gcc version 3.4.3 (Mandrakelinux
10.2 3.4.3-7mdk)
cc_compile_by : sdague
cc_compile_domain : (none)
cc_compile_date : Mon Nov 14 14:16:48 EST 2005
xend_config_format : 3
FIELDS
Not all fields will be explained here, but some of the less obvious
ones deserve explanation:
hw_caps
A vector showing what hardware capabilities are supported by
your processor. This is equivalent to, though more cryptic,
the flags field in /proc/cpuinfo on a normal Linux machine.
free_memory
Available memory (in MB) not allocated to Xen, or any other
domains.
xen_caps
The Xen version and architecture. Architecture values can be
one of: x86_32, x86_32p (i.e. PAE enabled), x86_64, ia64.
xen_changeset
The Xen mercurial changeset id. Very useful for determining
exactly what version of code your Xen system was built from.
log Print out the xend log. This log file can be found in
/var/log/xend.log.
top Executes the xentop command, which provides real time monitoring of
domains. Xentop is a curses interface, and reasonably self
explanatory.
uptime
Prints the current uptime of the domains running.
SCHEDULER SUBCOMMANDS
Xen ships with a number of domain schedulers, which can be set at boot
time with the sched= parameter on the Xen command line. By default
credit is used for scheduling.
sched-credit [ -d domain-id [ -w[=WEIGHT] | -c[=CAP] ] ]
Set credit scheduler parameters. The credit scheduler is a
proportional fair share CPU scheduler built from the ground up to
be work conserving on SMP hosts.
Each domain (including Domain0) is assigned a weight and a cap.
PARAMETERS
WEIGHT
A domain with a weight of 512 will get twice as much CPU as a
domain with a weight of 256 on a contended host. Legal weights
range from 1 to 65535 and the default is 256.
CAP The cap optionally fixes the maximum amount of CPU a domain
will be able to consume, even if the host system has idle CPU
cycles. The cap is expressed in percentage of one physical CPU:
100 is 1 physical CPU, 50 is half a CPU, 400 is 4 CPUs, etc.
The default, 0, means there is no upper cap.
sched-sedf period slice latency-hint extratime weight
Set Simple EDF (Earliest Deadline First) scheduler parameters.
This scheduler provides weighted CPU sharing in an intuitive way
and uses realtime-algorithms to ensure time guarantees. For more
information see docs/misc/sedf_scheduler_mini-HOWTO.txt in the Xen
distribution.
PARAMETERS
period
The normal EDF scheduling usage in nanoseconds
slice
The normal EDF scheduling usage in nanoseconds
latency-hint
Scaled period if domain is doing heavy I/O.
extratime
Flag for allowing domain to run in extra time.
weight
Another way of setting CPU slice.
EXAMPLES
normal EDF (20ms/5ms):
xm sched-sedf <dom-id> 20000000 5000000 0 0 0
best-effort domains (i.e. non-realtime):
xm sched-sedf <dom-id> 20000000 0 0 1 0
normal EDF (20ms/5ms) + share of extra-time:
xm sched-sedf <dom-id> 20000000 5000000 0 1 0
4 domains with weights 2:3:4:2
xm sched-sedf <d1> 0 0 0 0 2
xm sched-sedf <d2> 0 0 0 0 3
xm sched-sedf <d3> 0 0 0 0 4
xm sched-sedf <d4> 0 0 0 0 2
1 fully-specified (10ms/3ms) domain, 3 other domains share
available rest in 2:7:3 ratio:
xm sched-sedf <d1> 10000000 3000000 0 0 0
xm sched-sedf <d2> 0 0 0 0 2
xm sched-sedf <d3> 0 0 0 0 7
xm sched-sedf <d4> 0 0 0 0 3
VIRTUAL DEVICE COMMANDS
Most virtual devices can be added and removed while guests are running.
The effect to the guest OS is much the same as any hotplug event.
BLOCK DEVICES
block-attach domain-id be-dev fe-dev mode [bedomain-id]
Create a new virtual block device. This will trigger a hotplug
event for the guest.
OPTIONS
domain-id
The domain id of the guest domain that the device will be
attached to.
be-dev
The device in the backend domain (usually domain 0) to be
exported. This can be specified as a physical partition
(phy:sda7) or as a file mounted as loopback
(file://path/to/loop.iso).
fe-dev
How the device should be presented to the guest domain. It can
be specified as either a symbolic name, such as /dev/hdc, for
common devices, or by device id, such as 0x1400 (/dev/hdc
device id in hex).
mode
The access mode for the device from the guest domain.
Supported modes are w (read/write) or r (read-only).
bedomain-id
The back end domain hosting the device. This defaults to
domain 0.
EXAMPLES
Mount an ISO as a Disk
xm block-attach guestdomain file://path/to/dsl-2.0RC2.iso
/dev/hdc ro
This will mount the dsl ISO as /dev/hdc in the guestdomain as a
read only device. This will probably not be detected as a CD-
ROM by the guest, but mounting /dev/hdc manually will work.
block-detach domain-id devid [--force]
Detach a domain's virtual block device. devid may be the symbolic
name or the numeric device id given to the device by domain 0. You
will need to run xm block-list to determine that number.
Detaching the device requires the cooperation of the domain. If
the domain fails to release the device (perhaps because the domain
is hung or is still using the device), the detach will fail. The
--force parameter will forcefully detach the device, but may cause
IO errors in the domain.
block-list [-l|--long] domain-id
List virtual block devices for a domain. The returned output is
formatted as a list or as an S-Expression if the --long option was
given.
NETWORK DEVICES
network-attach domain-id [script=scriptname] [ip=ipaddr] [mac=macaddr]
[bridge=bridge-name] [backend=bedomain-id]
Creates a new network device in the domain specified by domain-id.
It takes the following optional options:
OPTIONS
script=scriptname
Use the specified script name to bring up the network. Defaults to
the default setting in xend-config.sxp for vif-script.
ip=ipaddr
Passes the specified IP Address to the adapter on creation.
mac=macaddr
The MAC address that the domain will see on its Ethernet device.
If the device is not specified it will be randomly generated with
the 00:16:3e vendor id prefix.
bridge=bridge-name
The name of the bridge to attach the vif to, in case you have more
than one. This defaults to xenbr0.
backend=bedomain-id
The backend domain id. By default this is domain 0.
network-detach domain-id devid
Removes the network device from the domain specified by domain-id.
devid is the virtual interface device number within the domain
(i.e. the 3 in vif22.3).
network-list [-l|--long]> domain-id
List virtual network interfaces for a domain. The returned output
is formatted as a list or as an S-Expression if the --long option
was given.
VIRTUAL TPM DEVICES
vtpm-list [-l|--long] domain-id
Show the virtual TPM device for a domain. The returned output is
formatted as a list or as an S-Expression if the --long option was
given.
SEE ALSOxmdomain.cfg(5), xentop(1)AUTHOR
Sean Dague <sean at dague dot net>
Daniel Stekloff <dsteklof at us dot ibm dot com>
Reiner Sailer <sailer at us dot ibm dot com>
Stefan Berger <stefanb at us dot ibm dot com>
BUGSxen-unstable 2013-06-14 xm(1)
