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How can I use bash to gather all NFS mount points with multiple configuration files to check that each mount is writeable?

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I am trying to create a script that will dynamically find all NFS mount points that should be writable and check that they are still writable however I can’t seem to get my head around connecting the mounts to their share directories.

So for example I have a server’s /etc/auto.master like this (I’ve sanitized some of the data):

/etc/auto.master
/nfs1        /etc/auto.nfs1 --ghost
/nfs2        /etc/auto.nfs2 --ghost

And each of those files has:

/etc/auto.nfs1
home   -rw,soft-intr -fstype=nfs server1:/shared/home
store  -rw,soft-intr -fstype=nfs server2:/shared/store

/etc/auto.nfs2
data   -rw,soft-intr -fstype=nfs oralceserver1:/shared/data
rman   -rw,soft-intr -fstype=nfs oracleserver1:/shared/rman

What I’m trying to get out of that is

/nfs1/home
/nfs1/store

/nfs2/data
/nfs2/rman

without getting any erroneous or commented entries caught in the net.

My code attempt is this:

#!/bin/bash

for automst in `grep '^/' /etc/auto.master|awk -F" " '{for(i=1;i<=NF;i++){if ($i ~ /etc/){print $i}}}'`;
do echo $automst > /tmp/auto.mst
done

AUTOMST=`cat /tmp/auto.mst`

for mastermount in `grep '^/' /etc/auto.master|awk -F" " '{for(i=1;i<=NF;i++){if ($i ~ /etc/){print $i}}}'`;
do grep . $mastermount|grep -v '#'|awk {'print $1'};
done > /tmp/nfsmounteddirs

for dir in `cat /tmp/nfsmounteddirs`;
do
if [ -w "$dir" ]; then echo "$dir is writeable"; else echo "$dir is not writeable!";fi
done

I have 600 Linux servers and many have their own individual NFS setups and we don’t have an alerting solution in place that can check, and while having all those individual scripts would be “a” solution, it would be a nightmare to manage and a lot of work so the dynamic aspect of it would be very useful.

Answer

awk '/^// {  # Process where lines begin with a /
             fil=$2; # Track the file name
             nfs=$1 # Track the nfs
             while (getline line < fil > 0) { # Read the fil specified by fil till the end of the file
                 split(line,map,","); # Split the lines in array map with , as the delimiter
                 split(map[1],map1,/[[:space:]]+/); # Further split map into map1 with spaces as the delimiter
                 if(map1[2]~/w/ && line !~ /^#/) { 
                   print nfs" "map1[1] # If w is in the permissions string and the line doesn't begin with a comment, print the nfs and share 
                 } 
             } 
             close(fil) # Close the file after we have finished reading
            }' /etc/auto.master

One liner:

awk '/^// { fil=$2;nfs=$1;while (getline line < fil > 0) { split(line,map,",");split(map[1],map1,/[[:space:]]+/);if(map1[2]~/w/ && line !~ /^#/) { print nfs" "map1[1] } } close(fil) }' /etc/auto.master

Output:

/nfs1 home
/nfs1 store
/nfs2 data
/nfs2 rman