1xl.conf(5) Xen xl.conf(5)
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6 /etc/xen/xl.conf - XL Global/Host Configuration
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9 The xl.conf file allows configuration of hostwide "xl" toolstack
10 options.
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12 For details of per-domain configuration options please see xl.cfg(5).
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15 The config file consists of a series of "KEY=VALUE" pairs.
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17 A value "VALUE" is one of:
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19 "STRING"
20 A string, surrounded by either single or double quotes.
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22 NUMBER
23 A number, in either decimal, octal (using a 0 prefix) or
24 hexadecimal (using an "0x" prefix).
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26 BOOLEAN
27 A "NUMBER" interpreted as "False" (0) or "True" (any other value).
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29 [ VALUE, VALUE, ... ]
30 A list of "VALUES" of the above types. Lists are homogeneous and
31 are not nested.
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33 The semantics of each "KEY" defines which form of "VALUE" is required.
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36 domid_policy="xen"|"random"
37 Determines how domain-id is set when creating a new domain.
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39 If set to "xen" then the hypervisor will allocate new domain-id
40 values on a sequential basis.
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42 If set to "random" then a random domain-id value will be chosen.
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44 Default: "xen"
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46 autoballoon="off"|"on"|"auto"
47 If set to "on" then "xl" will automatically reduce the amount of
48 memory assigned to domain 0 in order to free memory for new
49 domains.
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51 If set to "off" then "xl" will not automatically reduce the amount
52 of domain 0 memory.
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54 If set to "auto" then auto-ballooning will be disabled if the
55 "dom0_mem" option was provided on the Xen command line.
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57 You are strongly recommended to set this to "off" (or "auto") if
58 you use the "dom0_mem" hypervisor command line to reduce the amount
59 of memory given to domain 0 by default.
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61 Default: "auto"
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63 run_hotplug_scripts=BOOLEAN
64 If disabled hotplug scripts will be called from udev, as it used to
65 be in the previous releases. With the default option, hotplug
66 scripts will be launched by xl directly.
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68 Default: 1
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70 lockfile="PATH"
71 Sets the path to the lock file used by xl to serialise certain
72 operations (primarily domain creation).
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74 Default: "/var/lock/xl"
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76 max_grant_frames=NUMBER
77 Sets the default value for the "max_grant_frames" domain config
78 value.
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80 Default: value of Xen command line gnttab_max_frames parameter (or
81 its default value if unspecified).
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83 max_maptrack_frames=NUMBER
84 Sets the default value for the "max_maptrack_frames" domain config
85 value.
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87 Default: value of Xen command line gnttab_max_maptrack_frames
88 parameter (or its default value if unspecified).
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90 max_grant_version=NUMBER
91 Sets the default value for the "max_grant_version" domain config
92 value.
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94 Default: maximum grant version supported by the hypervisor.
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96 vif.default.script="PATH"
97 Configures the default hotplug script used by virtual network
98 devices.
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100 The old vifscript option is deprecated and should not be used.
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102 Default: "/etc/xen/scripts/vif-bridge"
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104 vif.default.bridge="NAME"
105 Configures the default bridge to set for virtual network devices.
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107 The old defaultbridge option is deprecated and should not be used.
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109 Default: "xenbr0"
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111 vif.default.backend="NAME"
112 Configures the default backend to set for virtual network devices.
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114 Default: 0
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116 vif.default.gatewaydev="NAME"
117 Configures the default gateway device to set for virtual network
118 devices.
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120 Default: "None"
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122 remus.default.netbufscript="PATH"
123 Configures the default script used by Remus to setup network
124 buffering.
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126 Default: "/etc/xen/scripts/remus-netbuf-setup"
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128 colo.default.proxyscript="PATH"
129 Configures the default script used by COLO to setup colo-proxy.
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131 Default: "/etc/xen/scripts/colo-proxy-setup"
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133 output_format="json|sxp"
134 Configures the default output format used by xl when printing
135 "machine readable" information. The default is to use the "JSON"
136 <https://www.json.org/> syntax. However for compatibility with the
137 previous "xm" toolstack this can be configured to use the old "SXP"
138 (S-Expression-like) syntax instead.
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140 Default: "json"
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142 blkdev_start="NAME"
143 Configures the name of the first block device to be used for
144 temporary block device allocations by the toolstack. The default
145 choice is "xvda".
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147 claim_mode=BOOLEAN
148 If this option is enabled then when a guest is created there will
149 be an guarantee that there is memory available for the guest. The
150 self-balloon mechanism can deflate/inflate the balloon quickly and
151 the amount of free memory (which "xl info" can show) is stale the
152 moment it is printed. When claim is enabled a reservation for the
153 amount of memory (see 'memory' in xl.conf(5)) is set, which is then
154 reduced as the domain's memory is populated and eventually reaches
155 zero. The free memory in "xl info" is the combination of the
156 hypervisor's free heap memory minus the outstanding claims value.
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158 If the reservation cannot be meet the guest creation fails
159 immediately instead of taking seconds/minutes (depending on the
160 size of the guest) while the guest is populated.
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162 Default: 1
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164 0 No claim is made. Memory population during guest creation will
165 be attempted as normal and may fail due to memory exhaustion.
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167 1 Free memory as reported by the hypervisor is used for
168 calculating whether there is enough memory free to launch a
169 guest. This guarantees immediate feedback whether the guest
170 can be launched due to memory exhaustion (which can take a long
171 time to find out if launching massively huge guests).
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173 vm.cpumask="CPULIST"
174 vm.hvm.cpumask="CPULIST"
175 vm.pv.cpumask="CPULIST"
176 Global masks that are applied when creating guests and pinning
177 vcpus to indicate which cpus they are allowed to run on.
178 Specifically, "vm.cpumask" applies to all guest types,
179 "vm.hvm.cpumask" applies to both HVM and PVH guests and
180 "vm.pv.cpumask" applies to PV guests.
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182 The hard affinity of guest's vcpus are logical-AND'ed with
183 respective masks. If the resulting affinity mask is empty,
184 operation will fail.
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186 Use --ignore-global-affinity-masks to skip applying global masks.
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188 The default value for these masks are all 1's, i.e. all cpus are
189 allowed.
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191 Due to bug(s), these options may not interact well with other
192 options concerning CPU affinity. One example is CPU pools. Users
193 should always double check that the required affinity has taken
194 effect.
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197 xl(1)
198 xl.cfg(5)
199 https://www.json.org/
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2034.17.2 2023-11-14 xl.conf(5)