Running CentOS 8
server side: /etc/exports: /home/share *(ro) /home and /home/share is owned by root.root and has 755 permissions on directories, 644 permission on files.
client side: mount -t nfs4 server:/ /sharefolder How do I directly mount /home/share to /sharefolder instead of mounting the root of the fs? If I try "mount -t nfs4 server:/home/share /sharefolder", I get an "Operation not permitted" error
mount -t nfs4 server:/home/share /sharefolder looks like a correct command client-side, and your set-up works for me as I just tested it.
Of course, you must enter the command as root, or use sudo with it. The "Operation not permitted" error message suggests perhaps you accidentally ran the command as a non-root user, or mistyped the share name.
Note that even if you export and mount just server:/home/share, the NFSv4 server will need to auto-generate virtual exports for / and /home. However, these will not be the NFS server's real / nor /home, but virtual read-only directories that only contain the minimum necessary sub-directories to reach the actually-exported directories. Once the share has been mounted, you can see this at /proc/fs/nfsd/exports on the NFS server:
cat /proc/fs/nfsd/exports # Version 1.1 # Path Client(Flags) # IPs /home *(ro,insecure,no_root_squash,sync,no_wdelay,no_subtree_check,v4root,uuid=e4c0fcd4:00b94db3:b63bd9a8:0e705e29,sec=390003:390004:390005:1) /home/share *(ro,root_squash,sync,wdelay,no_subtree_check,uuid=e4c0fcd4:00b94db3:b63bd9a8:0e705e29,sec=1) / *(ro,insecure,no_root_squash,sync,no_wdelay,no_subtree_check,v4root,fsid=0,uuid=e4c0fcd4:00b94db3:b63bd9a8:0e705e29,sec=390003:390004:390005:1) After a bit of testing I managed to reproduce your problem, and it turns out to be firewall issue. Please make sure firewall is disabled and verify that your nfs share works afterwards.
Assuming that you use firewalld:
sudo systemctl stop firewalld Once you determine that nfs works as expected you'll want to change your firewall configuration. nfs relies on other daemon processes so in order for nfs to work correctly, you need to let through not only nfs, but also mountd and rpc-bind
sudo firewall-cmd --permanent --add-service=rpc-bind sudo firewall-cmd --permanent --add-service=mountd sudo firewall-cmd --permanent --add-service=nfs sudo firewall-cmd --reload You can also specify a zone if you want these services allowed only for specific zone by adding i.e. --zone=nfszone
I haven't thoroughly tested this solution and you might need to open additional port in order to have all the functionalities working (i.e. file locking) See https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/storage_administration_guide/s2-nfs-nfs-firewall-config
