Samba and NFS shared folder on CentOS 8

Setting up a shared (guest) read-write folder across Samba and NFS was a piece of cake on CentOS 8. I’ve also thrown Avahi daemon into the mix so all three platforms we have in our family can easily access our data. Here are my notes.

First of, I’ve put my ethernet into trusted zone because I don’t want to deal with firewall in my home network. I am running one on router. You should probably not do this.

firewall-cmd --zone=trusted --change-interface=eno1
firewall-cmd --zone=trusted --change-interface=eno1 --permanent

For the record, my new NAS server is simply an 8th gen Intel NUC with a SSD for the OS and 2 TB Seagate drive for data. I don’t have much content just photos basically, unfortunately the bay is 9mm and there are no bigger 2.5-sized disks available. My plan is to extend it later with an external 4-6 TB USB3 or Thunderbolt HDD. I’ve configured LVM and the internal drive is mounted at /mnt/int. I don’t use RAID on my home NAS servers because I believe it’s not necessary - I can live with couple of days downtime until new disk arrives. Remember: RAID is not a backup! I regularly backup all the data to a remote location.

Overall goal is simple: have a single shared folder between Samba and NFS mounted read-write with SELinux turned on with minimum configuration as possible.

I’ve installed Samba, NFS server, SELinux utilities and Avahi daemon:

dnf install samba samba-client nfs-utils policycoreutils-python-utils avahi

Configuration of Samba could have been more simple as many of these values are probably default ones, I was just experimenting a bit and it won’t hurt for sure. This is /etc/samba/smb.conf:

[global]
    netbios name = NUC
    workgroup = WORKGROUP
    local master = yes
    security = user
    passdb backend = tdbsam
    guest account = nobody
    map to guest = Bad User
    logging = systemd
    log level = 0
    load printers = no

[data]
    comment = Data
    path = /mnt/int/data
    browseable = yes
    writeable = yes
    public = yes
    read only = no
    guest ok = yes
    guest only = yes
    force create mode = 0664
    force directory mode = 0775
    force user = nobody
    force group = nobody

The important SELinux “trick” was to configure file context correctly, so both NFS and Samba can access read and write it:

semanage fcontext -a -t public_content_rw_t "/mnt/int(/.*)?"
restorecon -RvvF /mnt/int

Both services also need to be allowed to write content:

setsebool -P allow_smbd_anon_write=1
setsebool -P allow_nfsd_anon_write=1

Configuration of NFSv4 in RHEL 8 (CentOS 8) is super easy. If you remember the pain of configuring firewalls with with older NFS versions like me, you want to disable those services completely. This step is optional if you want to allow legacy NFS clients:

/etc/nfs.conf:
[nfsd]
vers2=no
vers3=no

Stop and disable NFS services which are not needed for NFSv4:

systemctl mask --now rpc-statd.service rpcbind.service rpcbind.socket

End of the optional step. Configuration of NFS server is super easy (compare to Samba):

/etc/exports:
/mnt/int/data *(rw,async,all_squash,anonuid=65534,anongid=65534)

Since NFS server comes preinstalled in the default server CentOS8 installation profile, I restarted it.

systemctl restart nfs-server

And enabled Samba and Avahi services:

systemctl enable --now nmb.service smb.service nfs-server.service avahi-daemon.service

That’s really all. Testing is easy, install samba-client package and do:

smbclient -U guest //nuc/data

To test NFS, just mount the directory:

mount -t nfs nuc:/mnt/int/data /mnt/nuc

Hope the article helped you to achieve shared folder at home. This is not recommended setup for work or coffeeshops. And remember to do regular backups (not copies), because people can accidentaly rename, overwrite or delete files!

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