1xl.conf(5)                            Xen                           xl.conf(5)
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NAME

6       /etc/xen/xl.conf - XL Global/Host Configuration
7

DESCRIPTION

9       The xl.conf file allows configuration of hostwide "xl" toolstack
10       options.
11
12       For details of per-domain configuration options please see xl.cfg(5).
13

SYNTAX

15       The config file consists of a series of "KEY=VALUE" pairs.
16
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).
25
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.
32
33       The semantics of each "KEY" defines which form of "VALUE" is required.
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OPTIONS

36       domid_policy="xen"|"random"
37           Determines how domain-id is set when creating a new domain.
38
39           If set to "xen" then the hypervisor will allocate new domain-id
40           values on a sequential basis.
41
42           If set to "random" then a random domain-id value will be chosen.
43
44           Default: "xen"
45
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.
50
51           If set to "off" then "xl" will not automatically reduce the amount
52           of domain 0 memory.
53
54           If set to "auto" then auto-ballooning will be disabled if the
55           "dom0_mem" option was provided on the Xen command line.
56
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.
60
61           Default: "auto"
62
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.
67
68           Default: 1
69
70       lockfile="PATH"
71           Sets the path to the lock file used by xl to serialise certain
72           operations (primarily domain creation).
73
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.
79
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.
86
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.
93
94           The old vifscript option is deprecated and should not be used.
95
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.
100
101           The old defaultbridge option is deprecated and should not be used.
102
103           Default: "xenbr0"
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105       vif.default.backend="NAME"
106           Configures the default backend to set for virtual network devices.
107
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.
113
114           Default: "None"
115
116       remus.default.netbufscript="PATH"
117           Configures the default script used by Remus to setup network
118           buffering.
119
120           Default: "/etc/xen/scripts/remus-netbuf-setup"
121
122       colo.default.proxyscript="PATH"
123           Configures the default script used by COLO to setup colo-proxy.
124
125           Default: "/etc/xen/scripts/colo-proxy-setup"
126
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.
133
134           Default: "json"
135
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.
151
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
157
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).
166
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.
175
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.
179
180           Use --ignore-global-affinity-masks to skip applying global masks.
181
182           The default value for these masks are all 1's, i.e. all cpus are
183           allowed.
184
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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SEE ALSO

191       xl(1)
192       xl.cfg(5)
193       https://www.json.org/
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1974.14.2                            2021-05-04                        xl.conf(5)
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