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Accepted
alexus
Asked: 2014-07-09 08:23:20 +0800 CST

unable to write to mount point (nfs-server), getting "Permission denied"

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I'm trying to configure NFS between two RHEL7 nodes:

first node:

[root@ip-10-164-175-246 ~]# cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 7.0 (Maipo)
[root@ip-10-164-175-246 ~]# rpm -q nfs-utils
nfs-utils-1.3.0-0.el7.x86_64
[root@ip-10-164-175-246 ~]# cat /etc/exports
/var/www/html/  ip-10-184-161-46.ec2.internal(rw)
[root@ip-10-164-175-246 ~]#

second node:

[root@ip-10-184-161-46 ~]# mount ip-10-164-175-246.ec2.internal:/var/www/html/ /mnt/
[root@ip-10-184-161-46 ~]# touch /mnt/$$
touch: cannot touch ‘/mnt/3326’: Permission denied
[root@ip-10-184-161-46 ~]#

Why can't I write anything to /mnt/ over NFS?

nfs

1 Answers

  1. Best Answer

    Does your export utilize root_squash? From the CentOS docs:

    root_squash — Prevents root users connected remotely from having root privileges and assigns them the user ID for the user nfsnobody. This effectively "squashes" the power of the remote root user to the lowest local user, preventing unauthorized alteration of files on the remote server. Alternatively, the no_root_squash option turns off root squashing. To squash every remote user, including root, use the all_squash option. To specify the user and group IDs to use with remote users from a particular host, use the anonuid and anongid options, respectively. In this case, a special user account can be created for remote NFS users to share and specify (anonuid=,anongid=), where is the user ID number and is the group ID number.

    You'll need to add the flag no_root_squash to disable this, as it's on by default.

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