Howto log multiple sftpd instances with their chroot shared via NFS

Douglas E Engert deengert at
Wed Sep 29 23:34:29 AEST 2021

Thanks for the info on the single NFS volume mount.

Another take on the direct bind mount:

If server1 did:
source s_chroot_<username> { unix-stream("/var/data/chroot/<username>/dev/log_server1" optional(yes) ); };

Then for each user server1 would also do (or have in fstab):
mount -bind /var/data/chroot/<username>/dev/log /var/data/chroot/<username>/dev/log_server1

and server2 did:
source s_chroot_<username> { unix-stream("/var/data/chroot/<username>/dev/log_server1" optional(yes) ); };
and also do this:
mount -move /var/data/chroot/<username>/dev/log /var/data/chroot/<username>/dev/log_server2

This would allow each server to have its own /dev/log_host so they would not overwrite each others,
but when the libc went to write to the chrooted  /dev/log, the kernel would write to /dev/log_serverX because
the direct bind is in the host's kernel.

I have not tried this.

On 9/29/2021 3:42 AM, Hildegard Meier wrote:
> Hi, I tried now the following:
> Add the following line to /etc/fstab:
> /var/data/chroot                            /usr/local/sftp_chroot_bind_mount   none    bind                0       2
> Then:
> mkdir /usr/local/sftp_chroot_bind_mount
> mount /usr/local/sftp_chroot_bind_mount
> to bind-mount the users's chroot home to /usr/local/sftp_chroot_bind_mount
> Then replace in the syslog-ng config:
> source s_chroot_<username>    { unix-stream("/var/data/chroot/<username>/dev/log" optional(yes) ); };
> with
> source s_chroot_<username>    { unix-stream("/usr/local/sftp_chroot_bind_mount/<username>/dev/log" optional(yes) ); };
> Restart syslog-ng
> That would have been such a simple workaround.
> But unfortunately, the problem is not solved with this.
> The problem is the same, that there is sftp logging only on the sftp server where syslog-ng was restarted least.
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  Douglas E. Engert  <DEEngert at>

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