Provided by: xen-utils-common_4.9.2-0ubuntu1_all bug

NAME

       /etc/xen/xl.conf - XL Global/Host Configuration

DESCRIPTION

       The xl.conf file allows configuration of hostwide "xl" toolstack options.

       For details of per-domain configuration options please see xl.cfg(5).

SYNTAX

       The config file consists of a series of "KEY=VALUE" pairs.

       A value "VALUE" is one of:

       "STRING"
           A string, surrounded by either single or double quotes.

       NUMBER
           A number, in either decimal, octal (using a 0 prefix) or hexadecimal (using an "0x" prefix).

       BOOLEAN
           A "NUMBER" interpreted as "False" (0) or "True" (any other value).

       [ VALUE, VALUE, ... ]
           A list of "VALUES" of the above types. Lists are homogeneous and are not nested.

       The semantics of each "KEY" defines which form of "VALUE" is required.

OPTIONS

       autoballoon="off"|"on"|"auto"
           If set to "on" then "xl" will automatically reduce the amount of memory assigned to domain 0 in order
           to free memory for new domains.

           If set to "off" then "xl" will not automatically reduce the amount of domain 0 memory.

           If  set  to "auto" then auto-ballooning will be disabled if the "dom0_mem" option was provided on the
           Xen command line.

           You are strongly recommended to set this to "off" (or "auto") if you use  the  "dom0_mem"  hypervisor
           command line to reduce the amount of memory given to domain 0 by default.

           Default: "auto"

       run_hotplug_scripts=BOOLEAN
           If disabled hotplug scripts will be called from udev, as it used to be in the previous releases. With
           the default option, hotplug scripts will be launched by xl directly.

           Default: 1

       lockfile="PATH"
           Sets  the  path  to  the  lock  file  used  by  xl  to serialise certain operations (primarily domain
           creation).

           Default: "/var/lock/xl"

       vif.default.script="PATH"
           Configures the default hotplug script used by virtual network devices.

           The old vifscript option is deprecated and should not be used.

           Default: "/etc/xen/scripts/vif-bridge"

       vif.default.bridge="NAME"
           Configures the default bridge to set for virtual network devices.

           The old defaultbridge option is deprecated and should not be used.

           Default: "xenbr0"

       vif.default.backend="NAME"
           Configures the default backend to set for virtual network devices.

           Default: 0

       vif.default.gatewaydev="NAME"
           Configures the default gateway device to set for virtual network devices.

           Default: "None"

       remus.default.netbufscript="PATH"
           Configures the default script used by Remus to setup network buffering.

           Default: "/etc/xen/scripts/remus-netbuf-setup"

       colo.default.proxyscript="PATH"
           Configures the default script used by COLO to setup colo-proxy.

           Default: "/etc/xen/scripts/colo-proxy-setup"

       output_format="json|sxp"
           Configures the default output format used by xl when printing  "machine  readable"  information.  The
           default  is  to  use  the  "JSON"  <http://www.json.org/>  syntax. However for compatibility with the
           previous "xm" toolstack this can be configured  to  use  the  old  "SXP"  (S-Expression-like)  syntax
           instead.

           Default: "json"

       blkdev_start="NAME"
           Configures  the  name  of the first block device to be used for temporary block device allocations by
           the toolstack.  The default choice is "xvda".

       claim_mode=BOOLEAN
           If this option is enabled then when a guest is created there will  be  an  guarantee  that  there  is
           memory  available  for  the  guest.  This is an particularly acute problem on hosts with memory over-
           provisioned guests that use tmem and have self-balloon enabled (which is  the  default  option).  The
           self-balloon  mechanism  can deflate/inflate the balloon quickly and the amount of free memory (which
           "xl info" can show) is stale the moment it is printed. When claim is enabled a  reservation  for  the
           amount of memory (see 'memory' in xl.conf(5)) is set, which is then reduced as the domain's memory is
           populated  and  eventually  reaches  zero.   The  free  memory in "xl info" is the combination of the
           hypervisor's free heap memory minus the outstanding claims value.

           If  the  reservation  cannot  be  meet  the  guest  creation  fails  immediately  instead  of  taking
           seconds/minutes (depending on the size of the guest) while the guest is populated.

           Note  that to enable tmem type guests, one needs to provide "tmem" on the Xen hypervisor argument and
           as well on the Linux kernel command line.

           Note that the claim call is not attempted if "superpages" option is used in  the  guest  config  (see
           xl.cfg(5)).

           Default: 1

           0   No  claim  is  made.  Memory population during guest creation will be attempted as normal and may
               fail due to memory exhaustion.

           1   Normal memory and freeable pool of ephemeral pages (tmem) is used when calculating whether  there
               is  enough  memory  free to launch a guest.  This guarantees immediate feedback whether the guest
               can be launched due to memory exhaustion (which can take a long time to  find  out  if  launching
               massively huge guests).

SEE ALSO

       xl(1)
       xl.cfg(5)
       http://www.json.org/

4.9.2                                              2018-04-12                                         xl.conf(5)