Linux – nfs autofs automount of exported filesystems is empty on nfs server

autofsautomountlinuxnfsredhat

I am having issues with empty nfs automounts on the nfs server itself.

I'm running RHEL5.7 64bit exporting 4 directories as follows:

/export/site/server13 *(fsid=0,rw,sync,crossmnt)
/export/site/server13/u *(rw,sync)
/export/site/server13/unix *(rw,sync)
/export/site/server13/proj *(rw,sync)

The first location is on the root filesystem.

u, unix and proj are separate mounted filesystems.

I'm using NIS to supply automount maps to each server for the /site mountpoint.

auto.site.indirect:

server13        server13:/export/site/server13 \
/u              server13:/export/site/server13/u \
/unix           server13:/export/site/server13/unix \
/proj           server13:/export/site/server13/proj

On all the other servers in the NIS environment these exports automount with no problem to /site/server13/u etc, however on server13 itself the u, proj and unix directories are empty.

Any ideas please?

Update: I enabled logging for autofs which shows when I cd to /site/server13/u the server mounts /site/server13 but not the u share. It's as it it doesn't even try to mount the u share.

from /var/log/messages:

Jan 17 11:14:41 server13 automount[24326]: handle_packet: type = 3
Jan 17 11:14:41 server13 automount[24326]: handle_packet_missing_indirect: token 21, name server13, request pid 3385
Jan 17 11:14:41 server13 automount[24326]: attempting to mount entry /site/server13
Jan 17 11:14:41 server13 automount[24326]: lookup_mount: lookup(file): looking up server13
Jan 17 11:14:41 server13 automount[24326]: lookup_mount: lookup(file): server13 -> server13:/export/site/server13
Jan 17 11:14:41 server13 automount[24326]: parse_mount: parse(sun): expanded entry: server13:/export/site/server13
Jan 17 11:14:41 server13 automount[24326]: parse_mount: parse(sun): gathered options:
Jan 17 11:14:41 server13 automount[24326]: parse_mount: parse(sun): dequote("server13:/export/site/server13") -> server13:/export/site/server13
Jan 17 11:14:41 server13 automount[24326]: parse_mount: parse(sun): core of entry: options=, loc=server13:/export/site/server13
Jan 17 11:14:41 server13 automount[24326]: sun_mount: parse(sun): mounting root /site, mountpoint server13, what server13:/export/site/server13, fstype nfs, options (null)
Jan 17 11:14:41 server13 automount[24326]: mount_mount: mount(nfs): root=/site name=server13 what=server13:/export/site/server13, fstype=nfs, options=(null)
Jan 17 11:14:41 server13 automount[24326]: mount_mount: mount(nfs): calling mkdir_path /site/server13
Jan 17 11:14:41 server13 automount[24326]: mount_mount: mount(nfs): server13 is local, attempt bind mount
Jan 17 11:14:41 server13 automount[24326]: mount_mount: mount(bind): calling mkdir_path /site/server13
Jan 17 11:14:41 server13 automount[24326]: mount_mount: mount(bind): calling mount --bind -s  -o defaults /export/site/server13 /site/server13
Jan 17 11:14:41 server13 automount[24326]: mount_mount: mount(bind): mounted /export/site/server13 type bind on /site/server13
Jan 17 11:14:41 server13 automount[24326]: dev_ioctl_send_ready: token = 21
Jan 17 11:14:41 server13 automount[24326]: mounted /site/server13

Best Answer

I believe I've solved it.

auto.master refers to: /site /etc/auto_site_indirect

Previously this file contained:

thishost  -rw  server13:/export/site/server13
server13  -rw  server13:/export/site/server13
+auto.site.indirect

Now to manage the submounts it looks like this:

thishost  -rw  server13:/export/site/server13
*         -fstype=autofs,-Dhost=& file:/etc/auto.site.submounts

auto.site.submounts file:

*         server13:/export/site/server13/&

This method appears to be necessary for nfs submounts of mounted filesystems. Obviously I need a new indirect NIS map for /site, for server13 alone, that doesn't have the lines for server13 since they're configured locally now.

Related Solutions

Linux – Mount to NFS export of autofs mount shows empty contents

I think you have a cart before the horse problem here in that when you export a file system using NFS it locks on to the source direcotory. You are trying to not even have that source directory available at that time and only put something there via a mount later.

This will not work, because once you give NFS a handle on something to share, it will always share that thing, even if it ends up underneath a layer of mounts.

Let's say you setup a directory with a file 'frog' and export it with nfs:

[server] $ mkdir /mnt/test && touch /mnt/test/frog
[server] $ echo '/mnt/test *(ro)' >> /etc/exports
[server] $ exportfs -a

Then you mount it on a client somewhere, you will see the file frog as expected:

[client] $ mkdir /mnt/test
[client] $ mount -t nfs server:/mnt/test /mnt/test
[client] $ ls $/mnt/test
frog

Now let's say you mount something else on top of that folder on the server:

[server] $ mkdir /mnt/test2 && touch /mnt/test2/fish
[server] $ mount -o bind /mnt/test2 /mnt/test
[server] $ ls /mnt/test
fish

Spiffy. But what is nfs serving up?

[client] $ ls /mnt/test
frog

You can't even get to that file frog on the server because it's got a different thing mounted on top of it, but NFS is serving up that under layer!

To make a long story short, if you want to export your file systems via NFS you will need to have them mounted up properly at the time NFS starts up and exports them and they will need to stick around. Exporting file systems that are themselves mounted using autofs will never work quite right. You will need to permanently mount those ISOs in order to export them via NFS.

Automount works but autofs wont mount

I had the same issue, had to add ssh key from the root user when connecting to the remote machine, to allow passwordless ssh logins:


sudo su -

ssh-keygen -t rsa

ssh-copy-id -i ~/.ssh/id_rsa.pub remote_user@remote_server

try to ssh to the remote machine, you should not be asked for password.

restart autofs

Best Answer

Related Solutions

Linux – Mount to NFS export of autofs mount shows empty contents

Automount works but autofs wont mount

Related Topic