root/trunk/autofs.txt

AUTHOR:         Bryan Mason <bmason@bmason.com>

DATE:           2004-05-20
        
LICENSE:        GNU Free Documentation License Version 1.2 
                Copyright (c) 2003, Bryan Mason.
                Permission is granted to copy, distribute and/or modify
                this document under the terms of the GNU Free
                Documentation License, Version 1.2 or any later version
                published by the Free Software Foundation. A copy of the
                license can be found at
                http://www.gnu.org/copyleft/fdl.html.

SYNOPSIS:       Installing the version 4 autofs automounter on LFS

DESCRIPTION:    This hint describes how to install autofs 4 on a Linux
                From Scratch system.
                
ATTACHMENTS:    Patch for compiling autofs-4.1.2:
                http://www.bmason.com/LFS/autofs/unused-variables.patch
                
                Init scripts:
                http://www.bmason.com/LFS/autofs/autofs-initscripts.tar.gz
                
PREREQUISITES:  This hint assumes that you have already a working system
                and are comfortable with configuring and re-compiling
                the Linux kernel.  Although this hint was written based
                on LFS 3.3 (kernel 2.4.18), it should work equally well
                on newer LFS installations, although they have not been
                fully tested.

HINT:

Contents
========

    1. Introduction
    2. Configuring the Kernel for autofs Support
    3. Downloading, Configuring, and Compiling autofs
    4. Creating Initialization Scripts
    5. Configuring Mount Points
    6. Troubleshooting

1. Introduction
===============

    Automounting is the process of automatically mounting and unmounting
    of file systems by a daemon.  When a file in the file system is
    accessed, the automounter will automatically mount the file system.
    After a period of inactivity, the file system is automatically
    unmounted.  This can be extremely useful for network file systems
    (both SMB and NFS) as well as automatically mounting CD-ROM drives
    and floppy disk drives.
    
    There are two types of automounters in Linux, "AMD" and "autofs".
    AMD is implemented entirely as a user-space daemon.  Autofs includes
    both a user-space daemon and code in the kernel that assists the
    daemon.  There are currently two versions of autofs, v3 and v4.
    
    Although there are several good documents on how to configure autofs
    after installation, there seem to be few documents on how to compile
    and install the autofs package, which is where this document comes
    in.
    
    This document describes how to configure and compile autofs version
    4 for LFS and provides a boot script to start autofs.  It does not
    discuss AMD or how to configure autofs after it has been installed.
    There are two very good HOWTO's that describe the post-install
    configuration of autofs:

    "Automount mini-Howto"
        http://www.linux-consulting.com/Amd_AutoFS/autofs.html
    
    "Autofs Automounter HOWTO"
        http://www.tldp.org/HOWTO/Automount.html

    Installation of autofs consists of the following basic steps which 
    are described in more detail below:
    1) Configuring the Kernel for autofs support
    2) Downloading, configuring, and installing the autofs daemon, 
       man pages, and libraries
    3) Creating boot scripts to start the automount daemons
    
    If you have any comments or corrections to be made to this document,
    please send an e-mail message to the author at <bmason@bmason.com>.
    

2. Configuring the LFS Kernel for Autofs Support 
================================================

    To provide support for the automount user-space daemon, the 
    following options must be configured in the kernel, either
    as a module or as part of the kernel:
    
    In the "File Systems" section:
      - "Kernel automounter version 4 support (also supports v3)"
        (CONFIG_AUTOFS4_FS).
        
    In the "File Systems -> Network File Systems" section:
      - "NFS file system support" (CONFIG_NFS_FS)
      
    If you want to mount shares on Windows systems, you should also
    enable the "SMB file system support" (CONFIG_SMB_FS) option in the
    "File Systems -> Network File Systems" section.  In addition, you
    may need to install and configure Samba as described in Beyond Linux
    From Scratch (BLFS) at <http://www.linuxfromscratch.org/blfs/>.
      
    After the kernel is configured, proceed with the normal process of
    building and installing a new Linux kernel (make bzImage, make
    modules, make modules_install, copy the bzImage file, etc.)
    
    After the kernel has been recompiled, the following line should
    be added to /etc/modules.conf if automount support was compiled
    as a kernel module:
    
        alias autofs4 autofs


3. Downloading, Configuring, and Installing Autofs
==================================================

    Autofs can be downloaded from kernel.org at
        ftp://ftp.kernel.org/pub/linux/daemons/autofs/v4
        
    There are some problems compiling autofs 4.1.2 with gcc 2.95.3, so 
    you can download version 4.0.0 (autofs-4.0.0-1.tar.gz or
    autofs-4.0.0-1.tar.bz2), or apply the patch located at 
    <http://www.bmason.com/LFS/autofs/unused-variables.patch>
    
    To apply the patch, cd to "autofs-4.1.2/lib" and execute 
    "patch -Np1 < [path-to-patch]" where [path-to-patch] is the path to
    where you copied the patch on your system.
    
    The problem is that gcc 2.95.3 doesn't recognize the 
    "-Wno-unused-variables" option (although it does recognize 
    "-Wno-unused").  If later versions of gcc recognize the 
    "-Wno-unused-variables" option, then this patch is probably
    unnecessary.
    
    Configuration, building, and installation of autofs is
    straightforward.  Simply run the standard, "configure, make, 
    make install" routine:
    
        ./configure &&
        make &&
        make install
        
    This will install the following files to the following directories:
    
    Automount Daemon 
        Destination Directory:  /usr/sbin
        File:                   automount
    
    Man Files
        Destination Directory:  /usr/share/man/man5
        Files:                  auto.master.5
                                autofs.5
        Destination Directory:  /usr/share/man/man8
        Files:                  autofs.8
                                automount.8
    
    Configuration Files
        Destination Directory:  /etc
        Files:                  auto.master
                                auto.net
                                auto.misc
    
    Init Scripts
        Destination File:       /etc/rc.d/init.d
        File:                   autofs

    
    Libraries
        Destination Directory:  /usr/lib/autofs
        Files:                  lookup_file.so
                                lookup_program.so
                                mount_afs.so
                                mount_changer.so
                                mount_generic.so
                                lookup_multi.so
                                lookup_userhome.so
                                mount_autofs.so
                                mount_ext2.so
                                mount_nfs.so
                                lookup_nisplus.so
                                lookup_yp.so
                                mount_bind.so
                                mount_ext3.so
                                parse_sun.so


4. Creating Initialization Scripts
==================================

    The installation script installed by default will not run under LFS
    because it expects the distribution to be either Debian or Red Hat.
    the script looks for the files /etc/debian_version and 
    /etc/redhat-release, and if it doesn't find them, it complains and
    exits.

    I've created a new init script with a more LFS-style flavor.  The
    init script and configuration file is in a single tarball located at
    <http://www.bmason.com/LFS/autofs/autofs-initscripts.tar.gz>. The
    script performs the following functions:
    
    Start: the file /etc/auto.master will be read and the mount point(s)
    in the file will be created, if necessary.  Some basic checks are
    made to verify that the map files are there, and the automount
    daemon(s) will be started with the correct options to implement the
    mount point(s). Currently, only static map files and executable map
    files are supported (I don't know enough about yp, etc. to write the
    code to handle the more complex cases).
    
    Stop: all of the automount deamon(s) specified in /etc/auto.master,
    as well as all other automount process, will be stopped.
    
    Restart: the "stop" procedure is run, followed by a one-second
    delay, and then the "start" procedure is run.
    
    Reload: not implemented.
    
    Status: a list of configured mount points, followed by a list of the
    active automount deamon(s), and then a list of actively automounted
    directories (from mount) will be displayed.
    

5. Configuring Mount Points
===========================

    There are several good texts that describe how to configure
    mount points with autofs, so I won't describe how to do that
    here.
    
    The following Howto's describe how to configure autofs:
    "Automount mini-Howto"
        http://www.linux-consulting.com/Amd_AutoFS/autofs.html
    "Autofs Automounter HOWTO"
        http://www.tldp.org/HOWTO/Automount.html
        
     In addition, the following man pages contain descriptions
     of autofs and its configuration files:
     - auto.master(5)
     - autofs(5)
     - automount(8)
     - autofs(8)


6. Troubleshooting
==================

   Generally speaking, most problems are caused by problems in the
   configuration script (/etc/auto.master) and the associated map files
   (/etc/auto.misc, /etc/auto.net, and so forth).  Double-check the man
   pages and Howto's to make sure everything is OK.
   
   If you have some problems and have figured out a good way to overcome
   them, send me a message describing your problem/solutin and I'll add
   it to this section.
   
   If you find a bug in the init scripts please send a message to me at
   <bmason@bmason.com> so I can correct them.  Thank you.
   
   
ACKNOWLEDGEMENTS:
   
   R. Cort Tompkins <rtompkin@cs.odu.edu> wrote a hint on installing autofs
   version 3 on LFS.
    
 
CHANGELOG:
    [2004-05-20]
    * Originated