AutoFS under FreeBSD, as controlled by 'amd'. The purpose of AutoFS is
to mount volumes as they are needed and unmount them when they are not
in use. The same setup I used in the Linux write up is presented here,
wherein we have usres' home directories located elsewhere than "/home"
and remote documentation that is occasionally needed on the system.
The intention is presenting standardized directory structures across
systems even if the directory structure of origin may not be standard.
Our details for this are:
HOST (client): beastie (10.0.7.135)
HOST (NFS server): farnsworth (10.0.7.80)
OS: FreeBSD 8.2
Getting started, I've again set up group "sci" and 2 users, "rfeynman"and "pcherenkov". On this host, actual home directories are setup under
"/export/home", though our users' home directories are configured under
"/home":
beastie [0] /usr/sbin/pw groupadd -n sci beastie [0] /usr/bin/grep sci /etc/group sci:*:1001: beastie [0] /usr/sbin/pw useradd -g 1001 -c "R. Feynman" -d \ > /export/home/rfeynman -m -s /bin/ksh -n rfeynman beastie [0] /usr/sbin/pw useradd -g 1001 -c "P. Cherenkov" -d \ > /export/home/pcherenkov -m -s /bin/ksh -n pcherenkov beastie [0] /usr/bin/tail -2 /etc/passwd rfeynman:*:1001:1001:R. Feynman:/export/home/rfeynman:/bin/ksh pcherenkov:*:1002:1001:P. Cherenkov:/export/home/pcherenkov:/bin/kshIn the above, I've used 'pw' to set our users' home directories under
"/export/home", though this is simply so they are created with the
appropriate permissions and "skel" files. Also, their home directories
really do reside under "/export/home" but for commonality within the
environment, we'll configure them to "/home", letting 'amd' take care
of things later:
beastie [0] /usr/sbin/pw usermod -d /home/rfeynman -n rfeynman pw: WARNING: home `/home/rfeynman' does not exist beastie [0] /usr/sbin/pw usermod -d /home/pcherenkov -n pcherenkov pw: WARNING: home `/home/pcherenkov' does not exist beastie [0] /usr/bin/tail -2 /etc/passwd rfeynman:*:1001:1001:R. Feynman:/home/rfeynman:/bin/ksh pcherenkov:*:1002:1001:P. Cherenkov:/home/pcherenkov:/bin/kshNote in the above, we only tell 'pw usermod' to modify the configured
location of the users' home directories, but not to create them, hence
the missing "-m" option. Below we have our current mounted file systems
and "fstab" contents (the fstab will not change throughout this set up):
beastie [0] /bin/df -h Filesystem Size Used Avail Capacity Mounted on /dev/da0s1a 5.8G 1.9G 3.5G 35% / devfs 1.0K 1.0K 0B 100% /dev /dev/da0s1d 990M 866K 910M 0% /var /dev/da1s1a 1.9G 40K 1.8G 0% /export/home beastie [0] /usr/bin/grep -v ^# /etc/fstab /dev/da0s1b none swap sw 0 0 /dev/da0s1a / ufs rw 1 1 /dev/da0s1d /var ufs rw 2 2 /dev/acd0 /cdrom cd9660 ro,noauto 0 0 /dev/da1s1a /export/home ufs rw 2 2
Before configuring and starting 'amd', we do a directory listing of
"/home" and "/export/home", seeing that both are writable by root. Also,
while our users home directories are now configured under "/home", only "/export/home" has any contents:
beastie [0] /bin/ls -ld /home /export/home
drwxr-xr-x 5 root wheel 512 Oct 21 15:36 /export/home/
drwxr-xr-x 2 root wheel 512 Oct 21 15:32 /home/
beastie [0] /bin/ls -ld /home/* /export/home/*
ls: /home/*: No such file or directory
drwxr-xr-x 2 pcherenkov sci 512 Oct 21 15:36 /export/home/pcherenkov/
drwxr-xr-x 2 rfeynman sci 512 Oct 21 15:34 /export/home/rfeynman/
beastie [1]
We can now start our setup for 'amd' control of the home directories.
As a point of understanding, FreeBSD's "autofs" handling differs from
that seen elsewhere, such as Linux and Solaris. Whereas the latter
2 actually perform necessary mounts to the locations you configure,
FreeBSD's 'amd' mounts file systems as necessary under a common directory
(auto_dir) and creates symlinks under the paths you otherwise configure.
Using our home directories as the example (which we'll see later), if you
configure 'amd' to mount a path under "/home", the actual mount occurs
to a private 'amd' controlled directory and a symlink is placed under
"/home" referencing back to the 'amd' controlled directory. With that
in mind, below we create "/autopriv" for use by 'amd' for its handling
of mounts and "/etc/amdmaps" to contain our "autofs" map files:
beastie [0] /bin/mkdir /autopriv
beastie [0] /bin/mkdir /etc/amdmaps
Further, we setup a fairly generic 'amd' configuration at "/etc/amd.conf":
beastie [0] /bin/cat /etc/amd.conf
# global amd definitions (see 'am-utils' info(1) entry)
[ global ]
browsable_dirs = no
auto_dir = /autopriv
cache_duration = 300
dismount_interval = 120
pid_file = /var/run/amd.pid
restart_mounts = yes
search_path = /etc/amdmaps:/usr/local/etc/amdmaps
map_type = file
# amd maps
[ /home ]
map_name = auto.home
Our settings above in "[ global ]" setup "/autopriv" as the 'amd' mount
directory container and disallows browsing or listing of directory
structures not in use. Other settings of note is that our map type is
set to flat files (rather than NIS, etc.) and a search path for our map
files is set. The entry "[ /home ]" starts our auto map configuration
and sets the base directory to create links based on the configuration
of the subsequent map (auto.home) for "[ /home ]". In reviewing our map
"auto.home", the first line begins "/defaults", which sets any default
parameters for all other entries in "auto.home". Here, we only have
an option of "read-write", which given the following (and only) entry,
is fairly useless:
beastie [0] /bin/cat /etc/amdmaps/auto.home
/defaults opts:=rw
* type:=link;fs:=/export/home/${key}
The second line begins with a map "key", in this case, I've used "*"
which would translate out to the basename of our users' home directories.
The subsequent values are configuration parameters to 'amd', semicolon
(;) delimited. Since 'amd' doesn't play well with "nullfs" (or loop back)
mounts of locally mounted file systems, the first parameter simply tells
'amd' that the references under "/home" should be symlinks (thus why the
"rw" option is useless). These symlinks will point back to the values
set in the "fs" parameter. Of note, when 'amd' expands the key (*) for
the appropriate user upon access / login, the "${key}" variable becomes
available, hence the usage with "fs".
Now we need to start up our daemons. Since we will be using NFS with 'amd' in a later example, we'll configure that as well. (If you were only using local resources, like in our home directories example, in addition to the "amd" lines in rc.conf, you would need the "rpcbind" line since 'amd' uses rpc.):
beastie [0] /usr/bin/egrep 'rpc|nfs|amd' /etc/rc.conf
rpcbind_enable="YES"
rpc_lockd_enable="YES"
rpc_statd_enable="YES"
nfs_client_enable="YES"
amd_enable="YES"
amd_flags="-F /etc/amd.conf -l syslog"
beastie [0] for i in rpcbind statd lockd nfsclient ; do /etc/rc.d/${i} start ; \
> sleep 4 ; done
Starting rpcbind.
Starting statd.
Starting lockd.
NFS access cache time=60
beastie [0]
beastie [0] /etc/rc.d/amd start
Starting amd.
FreeBSD's 'amd' comes with a nice little utility called 'amq', which among
other things, allows one to stat the 'amd' process ID (amq -p) and to
list the mounted file systems, autofs maps, and their references (amq -m):
beastie [0] /usr/sbin/amq -p
1269
beastie [0] ps p 1269
PID TT STAT TIME COMMAND
1269 ?? Ss 0:00.01 /usr/sbin/amd -p -F /etc/amd.conf -l syslog
beastie [0] /usr/sbin/amq -m
"root" root 1 localhost is up
/dev/da0s1a / ufs 1 localhost is up
/dev/da0s1d /var ufs 1 localhost is up
/dev/da1s1a /export/home ufs 1 localhost is up
/etc/amdmaps/auto.home /home toplvl 1 localhost is up
Back to our home directories, a listing of "/home" and "/export/home"
effectively show the same data as before, but note, "/home" is now
read only:
beastie [0] /bin/ls -laF /home /export/home
/export/home:
total 10
drwxr-xr-x 5 root wheel 512 Oct 21 15:36 ./
drwxr-xr-x 3 root wheel 512 Oct 21 15:31 ../
drwxrwxr-x 2 root operator 512 Oct 21 15:30 .snap/
drwxr-xr-x 2 pcherenkov sci 512 Oct 21 15:36 pcherenkov/
drwxr-xr-x 2 rfeynman sci 512 Oct 21 15:34 rfeynman/
/home:
total 3
dr-xr-xr-x 2 root wheel 512 Oct 21 21:44 ./
drwxr-xr-x 26 root wheel 512 Oct 21 21:45 ../
Switching user to "rfeynman" drops us into "/export/home/rfeynman" (same
with login), however a simple 'cd' shows us back at "/home/rfeynman".
Further, we still have the same file systems mounted and we can see our
default "skel" files created:
beastie [0] /usr/bin/su - rfeynman
rfeynman@beastie [0] pwd
/export/home/rfeynman
rfeynman@beastie [0] cd ; pwd
/home/rfeynman
rfeynman@beastie [0] /bin/df -h
Filesystem Size Used Avail Capacity Mounted on
/dev/da0s1a 5.8G 1.9G 3.5G 35% /
devfs 1.0K 1.0K 0B 100% /dev
/dev/da0s1d 990M 898K 910M 0% /var
/dev/da1s1a 1.9G 40K 1.8G 0% /export/home
rfeynman@beastie [0] /bin/ls -laF
total 20
drwxr-xr-x 2 rfeynman sci 512 Oct 21 15:34 ./
drwxr-xr-x 5 root wheel 512 Oct 21 15:36 ../
-rw-r--r-- 1 rfeynman sci 763 Oct 21 15:34 .cshrc
-rw-r--r-- 1 rfeynman sci 261 Oct 21 15:34 .login
-rw-r--r-- 1 rfeynman sci 171 Oct 21 15:34 .login_conf
-rw------- 1 rfeynman sci 383 Oct 21 15:34 .mail_aliases
-rw-r--r-- 1 rfeynman sci 343 Oct 21 15:34 .mailrc
-rw-r--r-- 1 rfeynman sci 1247 Oct 21 21:47 .profile
-rw------- 1 rfeynman sci 288 Oct 21 15:34 .rhosts
-rw-r--r-- 1 rfeynman sci 984 Oct 21 15:34 .shrc
rfeynman@beastie [0] /bin/ls -laF /home
total 3
dr-xr-xr-x 2 root wheel 512 Oct 21 21:47 ./
drwxr-xr-x 26 root wheel 512 Oct 21 21:45 ../
lrwxrwxrwx 1 root wheel 21 Oct 21 21:47 rfeynman@ -> /export/home/rfeynman
rfeynman@beastie [0] touch trashfile
rfeynman@beastie [0] /bin/ls -li /home/rfeynman/trashfile /export/home/rfeynman/trashfile
235529 -rw-r--r-- 1 rfeynman sci 0 Oct 21 21:51 /export/home/rfeynman/trashfile
235529 -rw-r--r-- 1 rfeynman sci 0 Oct 21 21:51 /home/rfeynman/trashfile
rfeynman@beastie [0] exit
Above, our listing of "/home/rfeynman" shows it to be a symlink back to
"/export/home/rfeynman", and as we'd expect, creating and accessing files
under "/home/rfeynman" works just fine. Below, is simply a follow up
of the above using user "pcherenkov", and again, we see the symlinks
for the home directories:
beastie [0] /usr/bin/su - pcherenkov
pcherenkov@beastie [0] cd ; pwd
/home/pcherenkov
pcherenkov@beastie [0] /bin/ls -laF
total 20
drwxr-xr-x 2 pcherenkov sci 512 Oct 21 15:36 ./
drwxr-xr-x 5 root wheel 512 Oct 21 15:36 ../
-rw-r--r-- 1 pcherenkov sci 763 Oct 21 15:36 .cshrc
-rw-r--r-- 1 pcherenkov sci 261 Oct 21 15:36 .login
-rw-r--r-- 1 pcherenkov sci 171 Oct 21 15:36 .login_conf
-rw------- 1 pcherenkov sci 383 Oct 21 15:36 .mail_aliases
-rw-r--r-- 1 pcherenkov sci 343 Oct 21 15:36 .mailrc
-rw-r--r-- 1 pcherenkov sci 1247 Oct 21 20:59 .profile
-rw------- 1 pcherenkov sci 288 Oct 21 15:36 .rhosts
-rw-r--r-- 1 pcherenkov sci 984 Oct 21 15:36 .shrc
pcherenkov@beastie [0] /bin/ls -laF /home
total 4
dr-xr-xr-x 2 root wheel 512 Oct 21 21:53 ./
drwxr-xr-x 26 root wheel 512 Oct 21 21:45 ../
lrwxrwxrwx 1 root wheel 23 Oct 21 21:53 pcherenkov@ -> /export/home/pcherenkov
lrwxrwxrwx 1 root wheel 21 Oct 21 21:51 rfeynman@ -> /export/home/rfeynman
pcherenkov@beastie [0] exit
At this point, let's switch over to "as needed" remote mounts. Having
configured beastie as an NFS client earlier and farnsworth already
running an NFS server (see nfs.bsd), we can now configure 'amd' to read
our "autofs" map for "auto.info". First, I've appended stanza for "[
/opt ]" and its map to "amd.conf", followed by creating the "auto.info"
map with the contents seen below:
beastie [0] /usr/bin/tail -3 /etc/amd.conf
[ /opt ]
map_name = auto.info
beastie [0] /bin/cat /etc/amdmaps/auto.info
/defaults opts:=intr,bg
lhc-docs type:=nfs;opts:=intr,bg,ro;rhost:=farnsworth;\
rfs:=/export/${key}
man type:=nfs;\
addopts:=ro;\
rhost:=farnsworth;\
rfs:=/export/man
We still have our "/defaults" line, setting our base options for
the "auto.info" entries. Our keys are configured as "lhc-docs" and
"man", both of which will be presented again as symlinks under "/opt".
Our 'amd' parameters set both as type "nfs" and the remote host (rhost)
as farnsworth. In the "lhc-docs" entry, we've overridden the default
options (opts) and configured them to NFS options "intr,bg,ro". The
remote filesystem (rfs) is "/export/${key}", where key will be expanded to
"lhc-docs", which is the actual path on the NFS server farnsworth. In the
"man" entry, we've added to the default options (addopts), including "ro".
Additionally, rather than using a "${key}" variable, we've simply set it
directly. Of note in the above, while semicolons (;) delimit parameters
to 'amd' and white space isn't necessarily a problem, all options to a
key (lhc-docs, man) must be contained on a single line. To keep a map
files easily readable, you can break to the next line, providing you are
using escapes (\). Now that are configuration is complete, we'll restart
'amd' so it rereads its configuration and stat 'amd' with 'amq -m' again,
verifying it is reading our new map for "auto.info":
beastie [0] /etc/rc.d/amd restart
Stopping amd.
Waiting for PIDS: 1269.
Starting amd.
beastie [0] /usr/sbin/amq -m
"root" root 1 localhost is up
/dev/da0s1a / ufs 1 localhost is up
/dev/da0s1d /var ufs 1 localhost is up
/dev/da1s1a /export/home ufs 1 localhost is up
/etc/amdmaps/auto.home /home toplvl 1 localhost is up
/etc/amdmaps/auto.info /opt toplvl 1 localhost is up
Switching user to "pcherenkov", we make sure that our new "autofs"
configuration will work for our users:
beastie [0] /usr/bin/su - pcherenkov
pcherenkov@beastie [0] /bin/ls -al /opt
total 3
dr-xr-xr-x 2 root wheel 512 Oct 21 22:27 .
drwxr-xr-x 26 root wheel 512 Oct 21 22:27 ..
pcherenkov@beastie [0] /bin/ls -al /opt/lhc-docs
lrwxrwxrwx 1 root wheel 40 Oct 21 22:28 /opt/lhc-docs -> /autopriv/farnsworth/export/lhc-docs
pcherenkov@beastie [0] /bin/ls -al /opt/lhc-docs/
total 340
drwxr-xr-x 2 root wheel 512 Oct 21 16:06 .
dr-xr-xr-x 4 root wheel 512 Oct 21 22:28 ..
-rw-r--r-- 1 root wheel 1491 Oct 21 16:06 section.1
-rw-r--r-- 1 root wheel 109208 Oct 21 16:06 section.2
-rw-r--r-- 1 root wheel 45224 Oct 21 16:06 section.3
-rw-r--r-- 1 root wheel 106232 Oct 21 16:06 section.4
-rw-r--r-- 1 root wheel 76056 Oct 21 16:06 section.5
pcherenkov@beastie [0] /bin/df -h | /usr/bin/grep lhc-docs
farnsworth:/export/lhc-docs 5.8G 2.0G 3.4G 37% /autopriv/farnsworth/export/lhc-docs
Above, we see that a directory listing of "/opt" returns nothing of
interest due to our original 'amd' configuration disallowing directory
browsing. A directed listing of "/opt/lhc-docs", however, shows it to
be a symlink under the 'amd' controlled mount directory "/autopriv".
A further listing and we can stat the contents. The last thing we see
is that we now have an NFS mount back to farnsworth, courtesy of 'amd'.
Below, we see the contents of "/opt/lhc-docs" are fully accessible
for reading:
pcherenkov@beastie [0] /usr/bin/head -10 /opt/lhc-docs/section.1
[http://public.web.cern.ch/public/en/lhc/lhc-en.html]
The Large Hadron Collider
Our understanding of the Universe is about to change...
The Large Hadron Collider (LHC) is a gigantic scientific instrument near
Geneva, where it spans the border between Switzerland and France about
100m underground. It is a particle accelerator used by physicists to
study the smallest known particles – the fundamental building blocks of
all things. It will revolutionise our understanding, from the minuscule
Similary, we see below that the contents of "/opt/man" are accessible upon
request, simply by attempting to access a file contained on farnsworth's
remotely exported filesystem:
pcherenkov@beastie [0] /usr/bin/gunzip -c /opt/man/man1/vi.1.gz | \
> /usr/bin/groff -Tascii -man - | /usr/bin/head -20
VI(1) VI(1)
NAME
ex, vi, view - text editors
SYNOPSIS
ex [-eFGRrSsv] [-c cmd] [-t tag] [-w size] [file ...]
vi [-eFGlRrSv] [-c cmd] [-t tag] [-w size] [file ...]
view [-eFGRrSv] [-c cmd] [-t tag] [-w size] [file ...]
LICENSE
The vi program is freely redistributable. You are welcome to copy,
modify and share it with others under the conditions listed in the
LICENSE file. If any company (not individual!) finds vi sufficiently
useful that you would have purchased it, or if any company wishes to
redistribute it, contributions to the authors would be appreciated.
DESCRIPTION
pcherenkov@beastie [0] man -w -M /opt/man vi
/opt/man/man1/vi.1.gz
Seen below, I've simply included a few checks reviewing the state of
our mounts and symlinks:
pcherenkov@beastie [0] /sbin/mount | /usr/bin/grep farnsworth
farnsworth:/export/man on /autopriv/farnsworth/export/man (nfs, read-only)
farnsworth:/export/lhc-docs on /autopriv/farnsworth/export/lhc-docs (nfs, read-only)
pcherenkov@beastie [0] /bin/ls -al /opt
total 4
dr-xr-xr-x 2 root wheel 512 Oct 21 22:33 .
drwxr-xr-x 26 root wheel 512 Oct 21 22:27 ..
lrwxrwxrwx 1 root wheel 40 Oct 21 22:33 lhc-docs -> /autopriv/farnsworth/export/lhc-docs
lrwxrwxrwx 1 root wheel 35 Oct 21 22:32 man -> /autopriv/farnsworth/export/man
pcherenkov@beastie [0] /bin/df -h | /usr/bin/grep farnsworth
farnsworth:/export/man 5.8G 2.0G 3.4G 37% /autopriv/farnsworth/export/man
farnsworth:/export/lhc-docs 5.8G 2.0G 3.4G 37% /autopriv/farnsworth/export/lhc-docs
see also:Configuring AutoFS in Linux
http://www.am-utils.org/docs/am-utils/am-utils-all.html
Configuring NFS in FreeBSD (nfs.bsd)
