The /etc/fstab file contains static information about the filesystems. The file fstab contains descriptive information about the various file systems. Fstab is only read by programs, and not written; it is the duty of the system administrator to properly create and maintain this file. On booting your Linux Operating System, the basic functionality's services are loaded immediately to the Linux Kernel and continue to run until the login screen appears. On logging-in, other services, including the desktop programs, are loaded. These are called 'startup applications' or 'startup programs.' Automount NFS share in Linux using autofs by Pradeep Kumar Updated February 11, 2020 Autofs is a service in Linux like operating system which automatically mounts the file system and remote shares when it is accessed. Prepare Linux Client. In /etc/nsswitch.conf a ppend or create this line: Automount: files sss. In /etc/sssd/sssd.conf m odify this line under the sssd section to look like the following: services = nss, pam, autofs. Add the following empty section below sssd: autofs Add the following lines to the end of your domain yourdomain section.
- Ubuntu Mount Disk
- Linux Automount Usb
- Linux Automount Sd Card
- How To Configure Autofs
- Linux Automount Smb
- Linux Automount Usb
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System AdministrationAuthorImage:
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original in fr. FrédéricRaynal
fr to en Philippe Trbichand Emmanuel Bonnel
AboutTheAuthor:
FrédéricRaynal is preparing a computer science thesis in the INRIA. He loves reading (from Tolkien toBalzac) and listening to music (from Mozart to Philip Glass andfrom Led Zeppelin to Massive Attack or to Björk and BorisVian, but carefully avoiding rap, techno and some other noise ;-)Abstract:
automount and autofs are powerful tools and ease file systemsmanagement. They allow all the users of a same machine to mountdifferent file systems automatically the very moment they areneeded.ArticleIllustration:
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Introduction
Dependent on the physical support (hard disks, floppies, cdrom,..) and/or the operating system, the process of writing of data(not its meaning) is different : this is what we call file system(I hope experts and purists will forgive me for the short cuts ;-)The /etc/fstab file holds the hard mount points to beinstalled at boot time. Each point corresponds to a place and to afile system (for example, one of your hard disk partitions). Lateron, if you want to access other points, only root can use the mount(unless the special option 'user' is provided in /etc/fstab)command. As root, you must specify the mount point, what you wantto mount and possibly, the file system and some options. A commonuser not having, (fortunately ;-) the same rights, won't be able toaccess all the data.
Mount and fstab man pages give a more accurate and completedescription of these commands and concepts.
Both (automount, autofs) allow the administrator to configureall file systems a machine can access, the same way he would usingmount. The user can then access these systems in a fullytransparent manner, without worrying about how the kernel willanswer his request.
Description
The pair (automount, autofs) can be seen as the client/servermodel used in networking. A server is running, waiting for arequest. When a request comes, the server autoduplicates, one partanswering the request and the other one waiting for newrequests.
Here, autofs plays the role of the waiting server and automountthe one of the 'duplicated server'. The requests are hold inconfiguration files.
autofs
Usually, autofs is launched at boot time and is closed atshutdown (or reboot) time. Alfred 4 workflows. However, the administrator is able tostart or stop it 'manually'.
autofs can have 4 different options :
- start :
- as its name says, starts theproccess. When starting, autofs looks for 'maps' (maps specifyingmount points) in the configuration file /etc/auto.master. Then itstarts automount for every mount point. Next, autofs looks for NISmaps (we won't say more about yellow pages in this article);
- stop : stops autofs and allautomounts ;
- status : displays the present configurationand all running automounts ;
- reload : rereads the auto.master map andkills the no more appearing automounts and starts those for newmount points. Note that changes made in the maps are taken intoaccount at next startup. On the other hand, the changes made inauto.master imply an autofs restart.
In short, autofs is nothing else but a script consultingauto.master before starting the automounts associated to eachdescribed mount point.
automount
automout works from an initial mount point (the one found byautofs to start automount) and from a new map describing thefeatures of this initial mount point. The map associated to theautomount will hold all required information for mounting the filesystem automatically (hence the name ;-). This automatic mount isdone as soon as someone tries to accesses something in thedirectory tree starting from the mount point.
Next, the file systems are automatically 'unmount' after aninactive period (the default time out is 5 minutes).
Configuration
The configuration is done with the help of 2 files. The auto.masterfile, holding the mount points, and a mount point file providingthe system options for this specific mount point./etc/auto.master file
Here, we describe the maps using Sun format. The other format(hesiod) can't handle the syntax described below.
/etc/auto.master is the autofs's main file. Each line describesa mount point and refers to the file containing the file system'sdescriptions having to be mounted from that point. A last fieldallows to pass options to the mount to be started.
The line syntax is :
mount-point map-for-the-associated-automount [-mount-options-separated-by-comma ]
mount-point map-for-the-associated-automount [-mount-options-separated-by-comma ]
Example :
/home | /etc/auto.home | |
/misc | /etc/auto.misc | --timeout 60 |
/mnt | yp:mnt.map | -intr,nosuid,nodev |
This configures 3 mount points, /home, /misc and /mnt. To accessfiles in /misc, automount will read the file /etc/auto.misc to findthe mount options and the key associated to the file system.
The last 2 lines hold options. They are described in the mount manpage and are standardized. Browserfreedom 1 3 download free. As shown in the last line of theexample, autofs and automount are fully compatible with yellowpages maps (NIS and others).
The last 2 lines hold options. They are described in the mount manpage and are standardized. Browserfreedom 1 3 download free. As shown in the last line of theexample, autofs and automount are fully compatible with yellowpages maps (NIS and others).
Automount's maps
The syntax of this file is almost the same as the auto.masterone (it's normal since it's a map too ;-) :
key [ -mount-options-separated-by-comma ] place
The key represents an identifier for the file system under themount point . The place is the true physical location. key [ -mount-options-separated-by-comma ] place
Let's go back to the previous example with an /etc/auto.miscfile :
kernel | -ro,soft,intr | ftp.kernel.org:/pub/linux |
cdrom | -fstype=iso9660,ro | :/dev/cdrom |
floppy | -fstype=auto | :/dev/fd0 |
windoz | -fstype=vfat | :/dev/hda1 |
The absolute path to a file is then :
/mount-point/key/path/file
/mount-point/key/path/file
Then to read my windows config.sys, I just have to execute 'cat/misc/windoz/config.sys' and it accesses the /dev/hda1 device.
We can note that the first line of the file refers to an NFSexported directory (just to show the flexible use of automount andautofs ;-)
Last details
First, we must note that when we try to reach a file in one ofthe maps, the path completion is not working as usual. To avoidtyping the full path, we often use the TAB key automaticcompletion. If the map is not loaded, the key doesn't work. Goingback to the previous example, if I want to access the sameconfig.sys and I do :
%1 > cat /misc/ <TAB >
I will only get a disappointment 'beep' since it will find nothingto complete (don't mistake it with the happy 'beep' issued whenthere are several choices - to distinguish them, you have to type a<CTRL+D> and you can see all the available completionsappearing, if they are some).
%1 > cat /misc/ <TAB >
I will only get a disappointment 'beep' since it will find nothingto complete (don't mistake it with the happy 'beep' issued whenthere are several choices - to distinguish them, you have to type a<CTRL+D> and you can see all the available completionsappearing, if they are some).
As a matter of fact, this behavior is quite normal. Obviously,when you try to use completion, the directory's content is scanned,then you watch what matches the provided symbols. In that case, the/misc directory is empty since the goal is to mount the file systemonly when accessing it. On the other hand, you can't use completionuntil the mount point is automatically cancelled (i.e. when no moreresource is required from this file system and the time out isover).
Let's have a look at the result of a mount before and after theaccess to a map, considering the previous /etc/auto.master, with asingle mount : /dev/hda6 on / type ext2 (rw)
![Linux automount usb Linux automount usb](https://image.slidesharecdn.com/systemdtalk-150112095914-conversion-gate01/95/systemd-the-modern-linux-init-system-you-will-learn-to-love-15-638.jpg?cb=1421056921)
none on /proc type proc (rw)
/dev/hda9 on /home type ext2 (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
automount(pid362) on /home type autofs(rw,fd=5,pgrp=362,minproto=2,maxproto=3)
Ubuntu Mount Disk
automount(pid364) on /misc type autofs(rw,fd=5,pgrp=364,minproto=2,maxproto=3)automount(pid366) on /mnt type autofs(rw,fd=5,pgrp=366,minproto=2,maxproto=3)
Linux Automount Usb
Linux Automount Sd Card
We notice that there is a daemon (deamon - roughly a systemprocess) for each mount point. Furthermore, each associated 'type'is 'autofs'. After having viewed my /misc/windoz/config.sys, hereis the result of the mount :/dev/hda6 on / type ext2 (rw)
none on /proc type proc (rw)
How To Configure Autofs
/dev/hda9 on /home type ext2 (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
automount(pid362) on /home type autofs(rw,fd=5,pgrp=362,minproto=2,maxproto=3)
automount(pid364) on /misc type autofs(rw,fd=5,pgrp=364,minproto=2,maxproto=3)
automount(pid366) on /mnt type autofs(rw,fd=5,pgrp=366,minproto=2,maxproto=3)
/dev/hda1 on /misc/windoz type vfat (rw)
The last line holds what we expected :) If we wait 60 secondswithout accessing this mount point, it will disappear at nextmount.
Conclusion
Linux Automount Smb
On a personal computer running Linux and, for example, Windows,automount and autofs are rather useless, except to avoid a frequentroot login (what is, in fact, not so bad). Enough to define a mapfor the FAT and FAT32 partitions and so accessing data.
In the case of a network, the flexibility is even greater since,combined with yellow pages (we will study them in another serie ofarticles) and NFS among others, we can access everywhere withoutworrying about where we physically are.
Linux Automount Usb
A great benefit of automount is that a failing server will onlyaffect those clients that currently use this specific file server.This can reduce the down time in big companies (with perhaps 10 ormore nfs servers) significantly.