Setting Up an NFS Server and Accessing it from VMs in OpenStack¶

In environments like the Barcelona Supercomputing Center (BSC), where OpenStack volumes do not support multi-attachment, sharing data across multiple virtual machines (VMs) can be challenging. A Network File System (NFS) server provides a useful workaround by allowing multiple VMs to access the same file system over the network.

This guide explains how to set up an NFS server and how to mount the shared directory on OpenStack VMs.

🔐 OpenStack Security Group Rules for NFS Access¶

When setting up an NFS server and clients inside OpenStack, make sure your security group allows the necessary traffic.

Here’s a complete set of Ingress rules to configure via the OpenStack Dashboard > Network > Security Groups:

🔽 Ingress Rules (on the NFS Server)¶

Direction	Ether Type	Protocol	Port Range	Remote IP CIDR
Ingress	IPv4	TCP	111	192.168.0.0/24
Ingress	IPv4	UDP	111	192.168.0.0/24
Ingress	IPv4	TCP	2049	192.168.0.0/24
Ingress	IPv4	UDP	2049	192.168.0.0/24
Ingress	IPv4	TCP	20048	192.168.0.0/24
Ingress	IPv4	UDP	20048	192.168.0.0/24

🛠️ Step 1: Set Up the NFS Server¶

On the NFS Server VM¶

Install NFS server packages

For Debian/Ubuntu:

sudo apt update
sudo apt install nfs-kernel-server -y

For RHEL/CentOS:

sudo yum install nfs-utils -y
sudo systemctl enable --now nfs-server

Create a shared directory

sudo mkdir -p /mnt/nfs_share
sudo chown nobody:nogroup /mnt/nfs_share
sudo chmod 777 /mnt/nfs_share

Configure /etc/exports

Add the following line to /etc/exports to allow access from your VM subnet (e.g., 192.168.0.0/24):

/mnt/nfs_share 192.168.0.0/24(rw,sync,no_subtree_check)

Apply the export configuration

sudo exportfs -rav

Enable firewall rules (if applicable)

sudo ufw allow from 192.168.0.0/24 to any port nfs

On Each Client VM¶

Install NFS client