1nbdkit-client(1)                    NBDKIT                    nbdkit-client(1)
2
3
4

NAME

6       nbdkit-client - how to mount NBD filesystems on a client machine
7

DESCRIPTION

9       For NBD exports that contain filesystems there are several approaches
10       to mounting them on a client machine.
11
12       To ensure the nbd kernel module is loaded you may need to do:
13
14        # echo nbd > /etc/modules-load.d/nbd.conf
15
16       This will not take effect until you reboot, so also do:
17
18        # modprobe nbd
19
20   Easy mounting at boot time
21       For simple setups the following method is the easiest way to get an NBD
22       filesystem to mount at boot.  Create or edit /etc/rc.local or
23       /etc/rc.d/rc.local:
24
25        #!/bin/sh -
26        nm-online
27        modprobe nbd
28        nbd-client server /dev/nbd0
29        mount /dev/nbd0 /mnt
30
31   Mounting using systemd mount points
32       You can use systemd mount points to mount NBD filesystems at boot
33       and/or on demand.
34
35       Set up an nbdtab(5) mapping.  If /etc/nbdtab doesn't exist, then create
36       it first.  Add this line:
37
38        nbd0 server / bs=512,persist
39
40       As a workaround for https://github.com/NetworkBlockDevice/nbd/issues/91
41       you must currently modify the nbd@.service file:
42
43        # cp /usr/lib/systemd/system/nbd@.service /etc/systemd/system/
44        # vi /etc/systemd/system/nbd@.service
45
46       and edit or create these settings in the "[Service]" section:
47
48        [Service]
49        Type=oneshot
50        RemainAfterExit=yes
51        ExecStart=/usr/sbin/nbd-client %i
52        ExecStop=/usr/sbin/nbd-client -d /dev/%i
53
54       Finally create a systemd mount file called
55       /etc/systemd/system/mnt.mount:
56
57        [Unit]
58        Requires=nbd@nbd0.service
59        [Mount]
60        What=/dev/nbd0
61        Where=/mnt
62        Type=ext4
63
64       You can either reboot now or do:
65
66        # systemctl start mnt.mount
67
68       Other systemd services which need this mount point can depend on this
69       mount unit.
70

LIMITATIONS

72       Red Hat Enterprise Linux 8 enabled the "nbd.ko" Linux kernel module but
73       only for Unix domain sockets (ie. local connections).  This means you
74       cannot connect to an NBD server over a TCP network.  This also affects
75       Linux distributions derived from RHEL like CentOS, Alma and others.
76
77       This does not affect use of nbdkit as an NBD server, only the Linux
78       kernel as an NBD client.  Userspace Linux clients such as libnbd(3)
79       tools will work.
80

SEE ALSO

82       nbdkit(1), nbdkit-loop(1), nbdkit-service(1), nbd-client(8), nbdtab(5),
83       systemd(1), systemd.mount(5).
84

AUTHORS

86       Richard W.M. Jones
87

89       Copyright Red Hat
90

LICENSE

92       Redistribution and use in source and binary forms, with or without
93       modification, are permitted provided that the following conditions are
94       met:
95
96       •   Redistributions of source code must retain the above copyright
97           notice, this list of conditions and the following disclaimer.
98
99       •   Redistributions in binary form must reproduce the above copyright
100           notice, this list of conditions and the following disclaimer in the
101           documentation and/or other materials provided with the
102           distribution.
103
104       •   Neither the name of Red Hat nor the names of its contributors may
105           be used to endorse or promote products derived from this software
106           without specific prior written permission.
107
108       THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY
109       EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
110       IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
111       PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE
112       LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
113       CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
114       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
115       BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
116       WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
117       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
118       ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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122nbdkit-1.36.2                     2023-11-26                  nbdkit-client(1)
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