19 systemd filesystem mount automount

to add user to sudoers in Centos
[root@localhost ~]# usermod -aG wheel bit

================================

[bit@localhost ~]$ cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Sat Sep  9 22:05:18 2017
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/cl-root     /                       xfs     defaults        0 0
UUID=64f8607e-7764-4841-bd8b-3196bbea8223 /boot                   xfs     defaults        0 0
/dev/mapper/cl-swap     swap                    swap    defaults        0 0
[bit@localhost ~]$

=======================================

on systemd system you can mount filesystem via

1)/etc/fstab 

2)systemd

=======================================

[bit@localhost system]$ pwd

/usr/lib/systemd/system

[bit@localhost system]$ 

[bit@localhost system]$ cat tmp.mount 

#  This file is part of systemd.

#

#  systemd is free software; you can redistribute it and/or modify it

#  under the terms of the GNU Lesser General Public License as published by

#  the Free Software Foundation; either version 2.1 of the License, or

#  (at your option) any later version.

[Unit]

Description=Temporary Directory

Documentation=man:hier(7)

Documentation=http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems

ConditionPathIsSymbolicLink=!/tmp

DefaultDependencies=no

Conflicts=umount.target

Before=local-fs.target umount.target

After=swap.target

[Mount]

What=tmpfs  <<device

Where=/tmp <<directory

Type=tmpfs

Options=mode=1777,strictatime

# Make 'systemctl enable tmp.mount' work:

[Install]

WantedBy=local-fs.target

===============================

lvs — report information about logical volumes

[root@localhost ~]# lvs

  LV   VG Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert

  root cl -wi-ao---- 36.99g                                                    

  swap cl -wi-ao----  2.00g       

===============================
create mount folder

[root@localhost system]# mkdir /lvdisk

create lvdisk.mount file

[root@localhost system]# cat lvdisk.mount 

[Unit]

Description = my test mount

[Mount]

What = /dev/sda1 

Where = /lvdisk

Type = xfs

[Install]

WantedBy = graphical.target

[root@localhost system]# mount | grep lvdisk

/dev/sda1 on /lvdisk type xfs (rw,relatime,seclabel,attr2,inode64,noquota)

[root@localhost system]# umount /lvdisk

[root@localhost system]# mount | grep lvdisk

[root@localhost system]# systemctl start lvdisk.mount

[root@localhost system]# systemctl status lvdisk.mount 

● lvdisk.mount - my test mount

   Loaded: loaded (/etc/systemd/system/lvdisk.mount; enabled; vendor preset: disabled)

   Active: active (mounted) since Sat 2017-09-16 14:18:04 EDT; 7s ago

    Where: /lvdisk

     What: /dev/sda1

  Process: 10268 ExecMount=/bin/mount /dev/sda1 /lvdisk -t xfs (code=exited, status=0/SUCCESS)

Sep 16 14:18:04 localhost.localdomain systemd[1]: Mounting my test mount...

Sep 16 14:18:04 localhost.localdomain systemd[1]: Mounted my test mount.

[root@localhost system]# 

to ensure mount keep active after reboot:

[root@localhost system]# systemctl enable lvdisk.mount

Created symlink from /etc/systemd/system/graphical.target.wants/lvdisk.mount to /etc/systemd/system/lvdisk.mount.

====================================
automount

For automount we create the same mount file but we don't want it to be mounted.
we want mounting if some activity is on mount directory

before configuring automount, we have to stop lvdisk.mount
systemctl disable/stop lvdisk.mount

[bit@localhost system]$ sudo vim lvdisk.automount
[bit@localhost system]$ cat lvdisk.automount 
[Unit]
Description = lvdisk automount

[Automount]
Where = /lvdisk

[Install]
WantedBy = graphical.target
[bit@localhost system]$

lvdisk.automount must be the same name as lvdisk.automount


[bit@localhost system]$ cat lvdisk.mount 
[Unit]
Description = my test mount

[Mount]
What = /dev/sda1
Where = /lvdisk
Type = xfs

[Install]
WantedBy = graphical.target
[bit@localhost system]$ 

=====================================

[bit@localhost system]$ systemctl enable lvdisk.automount 

Created symlink from /etc/systemd/system/graphical.target.wants/lvdisk.automount to /etc/systemd/system/lvdisk.automount.

[bit@localhost system]$ systemctl start lvdisk.automount

[bit@localhost system]$ systemctl status lvdisk.automount 

● lvdisk.automount - lvdisk automount

   Loaded: loaded (/etc/systemd/system/lvdisk.automount; enabled; vendor preset: disabled)

   Active: active (waiting) since Sun 2017-09-17 09:08:58 EDT; 8s ago

    Where: /lvdisk

Sep 17 09:08:58 localhost.localdomain systemd[1]: Set up automount lvdisk automount.

Sep 17 09:08:58 localhost.localdomain systemd[1]: Starting lvdisk automount.

[bit@localhost system]$ systemctl status lvdisk.mount

● lvdisk.mount - my test mount

   Loaded: loaded (/etc/systemd/system/lvdisk.mount; disabled; vendor preset: disabled)

   Active: inactive (dead)

    Where: /lvdisk

     What: /dev/sda1

Sep 17 08:43:27 localhost.localdomain systemd[1]: Mounting my test mount...

Sep 17 08:43:27 localhost.localdomain systemd[1]: Mounted my test mount.

Sep 17 08:49:41 localhost.localdomain systemd[1]: Unmounting my test mount...

Sep 17 08:49:42 localhost.localdomain systemd[1]: Unmounted my test mount.

[bit@localhost system]$ 

======================
[bit@localhost system]$ mount | grep lvdisk
systemd-1 on /lvdisk type autofs (rw,relatime,fd=54,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
[bit@localhost system]$ cd /lvdisk/
[bit@localhost lvdisk]$ systemctl status lvdisk.mount
● lvdisk.mount - my test mount
   Loaded: loaded (/etc/systemd/system/lvdisk.mount; disabled; vendor preset: disabled)
   Active: active (mounted) since Sun 2017-09-17 09:11:32 EDT; 3s ago
    Where: /lvdisk
     What: /dev/sda1
  Process: 4164 ExecMount=/bin/mount /dev/sda1 /lvdisk -t xfs (code=exited, status=0/SUCCESS)

Sep 17 09:11:32 localhost.localdomain systemd[1]: Mounting my test mount...
Sep 17 09:11:32 localhost.localdomain systemd[1]: Mounted my test mount.
[bit@localhost lvdisk]$