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 vif.default.script="PATH"
91 Configures the default hotplug script used by virtual network
92 devices.
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94 The old vifscript option is deprecated and should not be used.
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96 Default: "/etc/xen/scripts/vif-bridge"
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98 vif.default.bridge="NAME"
99 Configures the default bridge to set for virtual network devices.
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101 The old defaultbridge option is deprecated and should not be used.
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103 Default: "xenbr0"
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105 vif.default.backend="NAME"
106 Configures the default backend to set for virtual network devices.
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108 Default: 0
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110 vif.default.gatewaydev="NAME"
111 Configures the default gateway device to set for virtual network
112 devices.
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114 Default: "None"
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116 remus.default.netbufscript="PATH"
117 Configures the default script used by Remus to setup network
118 buffering.
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120 Default: "/etc/xen/scripts/remus-netbuf-setup"
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122 colo.default.proxyscript="PATH"
123 Configures the default script used by COLO to setup colo-proxy.
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125 Default: "/etc/xen/scripts/colo-proxy-setup"
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127 output_format="json|sxp"
128 Configures the default output format used by xl when printing
129 "machine readable" information. The default is to use the "JSON"
130 <https://www.json.org/> syntax. However for compatibility with the
131 previous "xm" toolstack this can be configured to use the old "SXP"
132 (S-Expression-like) syntax instead.
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134 Default: "json"
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136 blkdev_start="NAME"
137 Configures the name of the first block device to be used for
138 temporary block device allocations by the toolstack. The default
139 choice is "xvda".
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141 claim_mode=BOOLEAN
142 If this option is enabled then when a guest is created there will
143 be an guarantee that there is memory available for the guest. The
144 self-balloon mechanism can deflate/inflate the balloon quickly and
145 the amount of free memory (which "xl info" can show) is stale the
146 moment it is printed. When claim is enabled a reservation for the
147 amount of memory (see 'memory' in xl.conf(5)) is set, which is then
148 reduced as the domain's memory is populated and eventually reaches
149 zero. The free memory in "xl info" is the combination of the
150 hypervisor's free heap memory minus the outstanding claims value.
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152 If the reservation cannot be meet the guest creation fails
153 immediately instead of taking seconds/minutes (depending on the
154 size of the guest) while the guest is populated.
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156 Default: 1
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158 0 No claim is made. Memory population during guest creation will
159 be attempted as normal and may fail due to memory exhaustion.
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161 1 Free memory as reported by the hypervisor is used for
162 calculating whether there is enough memory free to launch a
163 guest. This guarantees immediate feedback whether the guest
164 can be launched due to memory exhaustion (which can take a long
165 time to find out if launching massively huge guests).
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167 vm.cpumask="CPULIST"
168 vm.hvm.cpumask="CPULIST"
169 vm.pv.cpumask="CPULIST"
170 Global masks that are applied when creating guests and pinning
171 vcpus to indicate which cpus they are allowed to run on.
172 Specifically, "vm.cpumask" applies to all guest types,
173 "vm.hvm.cpumask" applies to both HVM and PVH guests and
174 "vm.pv.cpumask" applies to PV guests.
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176 The hard affinity of guest's vcpus are logical-AND'ed with
177 respective masks. If the resulting affinity mask is empty,
178 operation will fail.
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180 Use --ignore-global-affinity-masks to skip applying global masks.
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182 The default value for these masks are all 1's, i.e. all cpus are
183 allowed.
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185 Due to bug(s), these options may not interact well with other
186 options concerning CPU affinity. One example is CPU pools. Users
187 should always double check that the required affinity has taken
188 effect.
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191 xl(1)
192 xl.cfg(5)
193 https://www.json.org/
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1974.14.1 2021-03-18 xl.conf(5)