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25.Dd May 31, 2021
26.Dt ZFS-MOUNT-GENERATOR 8
27.Os
28.
29.Sh NAME
30.Nm zfs-mount-generator
31.Nd generate systemd mount units for ZFS filesystems
32.Sh SYNOPSIS
33.Pa @systemdgeneratordir@/zfs-mount-generator
34.
35.Sh DESCRIPTION
36.Nm
37is a
38.Xr systemd.generator 7
39that generates native
40.Xr systemd.mount 5
41units for configured ZFS datasets.
42.
43.Ss Properties
44.Bl -tag -compact -width "org.openzfs.systemd:required-by=unit[ unit]…"
45.It Sy mountpoint Ns =
46.No Skipped if Sy legacy No or Sy none .
47.
48.It Sy canmount Ns =
49.No Skipped if Sy off .
50.No Skipped if only Sy noauto
51datasets exist for a given mountpoint and there's more than one.
52.No Datasets with Sy yes No take precedence over ones with Sy noauto No for the same mountpoint .
53.No Sets logical Em noauto No flag if Sy noauto .
54Encryption roots always generate
55.Sy zfs-load-key@ Ns Ar root Ns Sy .service ,
56even if
57.Sy off .
58.
59.It Sy atime Ns = , Sy relatime Ns = , Sy devices Ns = , Sy exec Ns = , Sy readonly Ns = , Sy setuid Ns = , Sy nbmand Ns =
60Used to generate mount options equivalent to
61.Nm zfs Cm mount .
62.
63.It Sy encroot Ns = , Sy keylocation Ns =
64If the dataset is an encryption root, its mount unit will bind to
65.Sy zfs-load-key@ Ns Ar root Ns Sy .service ,
66with additional dependencies as follows:
67.Bl -tag -compact -offset Ds -width "keylocation=https://URL (et al.)"
68.It Sy keylocation Ns = Ns Sy prompt
69None, uses
70.Xr systemd-ask-password 1
71.It Sy keylocation Ns = Ns Sy https:// Ns Ar URL Pq et al.\&
72.Sy Wants Ns = , Sy After Ns = : Pa network-online.target
73.It Sy keylocation Ns = Ns Sy file:// Ns < Ns Ar path Ns >
74.Sy RequiresMountsFor Ns = Ns Ar path
75.El
76.
77The service also uses the same
78.Sy Wants Ns = ,
79.Sy After Ns = ,
80.Sy Requires Ns = , No and
81.Sy RequiresMountsFor Ns = ,
82as the mount unit.
83.
84.It Sy org.openzfs.systemd:requires Ns = Ns Pa path Ns Oo " " Ns Pa path Oc Ns …
85.No Sets Sy Requires Ns = for the mount- and key-loading unit.
86.
87.It Sy org.openzfs.systemd:requires-mounts-for Ns = Ns Pa path Ns Oo " " Ns Pa path Oc Ns …
88.No Sets Sy RequiresMountsFor Ns = for the mount- and key-loading unit.
89.
90.It Sy org.openzfs.systemd:before Ns = Ns Pa unit Ns Oo " " Ns Pa unit Oc Ns …
91.No Sets Sy Before Ns = for the mount unit.
92.
93.It Sy org.openzfs.systemd:after Ns = Ns Pa unit Ns Oo " " Ns Pa unit Oc Ns …
94.No Sets Sy After Ns = for the mount unit.
95.
96.It Sy org.openzfs.systemd:wanted-by Ns = Ns Pa unit Ns Oo " " Ns Pa unit Oc Ns …
97.No Sets logical Em noauto No flag (see below) .
98.No If not Sy none , No sets Sy WantedBy Ns = for the mount unit.
99.It Sy org.openzfs.systemd:required-by Ns = Ns Pa unit Ns Oo " " Ns Pa unit Oc Ns …
100.No Sets logical Em noauto No flag (see below) .
101.No If not Sy none , No sets Sy RequiredBy Ns = for the mount unit.
102.
103.It Sy org.openzfs.systemd:nofail Ns = Ns (unset) Ns | Ns Sy on Ns | Ns Sy off
104Waxes or wanes strength of default reverse dependencies of the mount unit, see
105below.
106.
107.It Sy org.openzfs.systemd:ignore Ns = Ns Sy on Ns | Ns Sy off
108.No Skip if Sy on .
109.No Defaults to Sy off .
110.El
111.
112.Ss Unit Ordering And Dependencies
113Additionally, unless the pool the dataset resides on
114is imported at generation time, both units gain
115.Sy Wants Ns = Ns Pa zfs-import.target
116and
117.Sy After Ns = Ns Pa zfs-import.target .
118.Pp
119Additionally, unless the logical
120.Em noauto
121flag is set, the mount unit gains a reverse-dependency for
122.Pa local-fs.target
123of strength
124.Bl -tag -compact -offset Ds -width "(unset)"
125.It (unset)
126.Sy WantedBy Ns = No + Sy Before Ns =
127.It Sy on
128.Sy WantedBy Ns =
129.It Sy off
130.Sy RequiredBy Ns = No + Sy Before Ns =
131.El
132.
133.Ss Cache File
134Because ZFS pools may not be available very early in the boot process,
135information on ZFS mountpoints must be stored separately.
136The output of
137.Dl Nm zfs Cm list Fl Ho Ar name , Ns Aq every property above in order
138for datasets that should be mounted by systemd should be kept at
139.Pa @sysconfdir@/zfs/zfs-list.cache/ Ns Ar poolname ,
140and, if writeable, will be kept synchronized for the entire pool by the
141.Pa history_event-zfs-list-cacher.sh
142ZEDLET, if enabled
143.Pq see Xr zed 8 .
144.
145.Sh ENVIRONMENT
146If the
147.Sy ZFS_DEBUG
148environment variable is nonzero
149.Pq or unset and Pa /proc/cmdline No contains Qq Sy debug ,
150print summary accounting information at the end.
151.
152.Sh EXAMPLES
153To begin, enable tracking for the pool:
154.Dl # Nm touch Pa @sysconfdir@/zfs/zfs-list.cache/ Ns Ar poolname
155Then enable the tracking ZEDLET:
156.Dl # Nm ln Fl s Pa @zfsexecdir@/zed.d/history_event-zfs-list-cacher.sh @sysconfdir@/zfs/zed.d
157.Dl # Nm systemctl Cm enable Pa zfs-zed.service
158.Dl # Nm systemctl Cm restart Pa zfs-zed.service
159.Pp
160If no history event is in the queue,
161inject one to ensure the ZEDLET runs to refresh the cache file
162by setting a monitored property somewhere on the pool:
163.Dl # Nm zfs Cm set Sy relatime Ns = Ns Sy off Ar poolname/dset
164.Dl # Nm zfs Cm inherit Sy relatime Ar poolname/dset
165.Pp
166To test the generator output:
167.Dl $ Nm mkdir Pa /tmp/zfs-mount-generator
168.Dl $ Nm @systemdgeneratordir@/zfs-mount-generator Pa /tmp/zfs-mount-generator
169.
170If the generated units are satisfactory, instruct
171.Nm systemd
172to re-run all generators:
173.Dl # Nm systemctl daemon-reload
174.
175.Sh SEE ALSO
176.Xr systemd.mount 5 ,
177.Xr systemd.target 5 ,
178.Xr zfs 5 ,
179.Xr systemd.generator 7 ,
180.Xr systemd.special 7 ,
181.Xr zed 8 ,
182.Xr zpool-events 8
183