Issues with autofs "problem reading master map, maximum wait exceeded"

Question

I am trying to mount a cifs partition using autofs. After a lot of trial and errors, I finally manage to get it mounted (the main issue I ran into is that in the instructions, here, this line in the mapping file

"[any_name] -fstype=cifs,[other_options] > ://[remote_server]/[remote_share_name]"

should really be:

"[remote_share_name] -fstype=cifs,[other_options] ://[remote_server]/"

At any rate after all this, I am able to mount my cifs partition using this command:

sudo automount -f -d &

Unfortunately, when I use the actual autofs service using the command below, my share does not get mounted

sudo /sbin/service autofs restart

I looked at the log files using after configuring autofs sysconfig to be in debug mode, and see the following errors:

Dec 18 13:33:51 SRVR_XYZ automount[7986]: autofs stopped
Dec 18 13:46:09 SRVR_XYZ automount[8740]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:46:09 SRVR_XYZ automount[8740]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:46:11 SRVR_XYZ automount[8740]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:46:13 SRVR_XYZ automount[8740]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:46:15 SRVR_XYZ automount[8740]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:46:17 SRVR_XYZ automount[8740]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:46:19 SRVR_XYZ automount[8740]: problem reading master map, maximum wait exceeded
Dec 18 13:46:19 SRVR_XYZ automount[8740]: automount: warning: could not read at least one map source after waiting, continuing ...
Dec 18 13:46:19 SRVR_XYZ automount[8740]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:53:34 SRVR_XYZ automount[9139]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:53:34 SRVR_XYZ automount[9139]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:53:36 SRVR_XYZ automount[9139]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:53:38 SRVR_XYZ automount[9139]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:53:40 SRVR_XYZ automount[9139]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:53:42 SRVR_XYZ automount[9139]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:53:44 SRVR_XYZ automount[9139]: problem reading master map, maximum wait exceeded
Dec 18 13:53:44 SRVR_XYZ automount[9139]: automount: warning: could not read at least one map source after waiting, continuing ...
Dec 18 13:53:44 SRVR_XYZ automount[9139]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:54:18 SRVR_XYZ automount[9250]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:54:18 SRVR_XYZ automount[9250]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:54:20 SRVR_XYZ automount[9250]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:54:22 SRVR_XYZ automount[9250]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:54:24 SRVR_XYZ automount[9250]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:54:26 SRVR_XYZ automount[9250]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master
Dec 18 13:54:28 SRVR_XYZ automount[9250]: problem reading master map, maximum wait exceeded
Dec 18 13:54:28 SRVR_XYZ automount[9250]: automount: warning: could not read at least one map source after waiting, continuing ...
Dec 18 13:54:28 SRVR_XYZ automount[9250]: lookup_read_master: lookup(file): could not open master map file /etc/auto.master

I have no idea why this is I made sure to set the proper permissions (chmod 640) and ownership of /etc/auto.master to the root account.

I have no idea why autofs service cannot mount the partition, while it works properly when I manually launch automout.

I use:

Automount version 5.0.5-133.el6_9
Linux distro: CentOS release 6.9(Final)

Here is how the /etc/auto.master file looks like:

#
# Sample auto.master file
# This is a 'master' automounter map and it has the following format:
# mount-point [map-type[,format]:]map [options]
# For details of the format look at auto.master(5).
#
/misc   /etc/auto.misc
#
# NOTE: mounts done from a hosts map will be mounted with the
#       "nosuid" and "nodev" options unless the "suid" and "dev"
#       options are explicitly given.
#
/net    -hosts
#
# Include central master map if it can be found using
# nsswitch sources.
#
# Note that if there are entries for /net or /misc (as
# above) in the included master map any keys that are the
# same will not be seen as the first read key seen takes
# precedence.
#
+auto.master
/mnt/cifs /etc/auto.cifs-shares --ghost

Thanks in advance for your help.

score 1 · Answer 1 · answered Feb 14 '18 at 15:39

AutoFS uses a two-level hierarchy of configuration files.

Top-level control /etc/auto.master

The top-most file in the hierarchy is /etc/auto.master and it defines the directory trees over which AutoFS has control. Your example file in your question had three non-comment lines:
```
/misc   /etc/auto.misc
/net    -hosts
+auto.master
```
This says that /misc is to be managed through AutoFS by the file or script /etc/auto.misc, and that /net is to be derived from the set of "Known hosts running NFS". The final line says that NIS should be consulted for a central map. You will not be running NIS so that line is irrelevant.

I would suggest that you comment out the /net and the +auto.master lines leaving just the /misc /etc/auto.misc definition.
Second level implementation

Now we have only one file remaining for the second level of the hierarchy, /etc/auto.misc. We can edit that to include your new definition:
```
[share_name] -fstype=cifs,[other_options] ://[remote_server]/[remote_share]"
```
For example, this entry will create a transient entry /misc/myshare that maps directly to the share //CIFSSERVER/ITSSHARE:
```
myshare -fstype=cifs,noperm,credentials=/root/.cifscred ://cifsserver/itsshare
```
Note that until the share is accessed by explicit name it will not appear in /misc. You can see errors reported in the logger (/var/log/syslog on my version of Debian, for example).

Personally I like to rename /misc as /var/autofs/misc in /etc/auto.master so that it's not in the way, and create a top level directory /autofs with symlinks to the known entries in /var/autofs/misc. In my example's case,

# Prepare the /etc/auto.master file
#
mkdir -p -m755 /var/autofs/misc /autofs
rmdir /misc
sed -i.bak 's!^/misc!/var/autofs/misc!' /etc/auto.master

# Create the symlink
#
cd /autofs
ln -s ../var/autofs/misc/myshare

and I would then reference AutoFS mounts in /autofs. You may find this doesn't work for you, especially if AutoFS-mounting filesystems is a slow/expensive process, but it saves me having to remember all the AutoFS mount names.

Issues with autofs "problem reading master map, maximum wait exceeded"

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