Configure NFS volume mounts for services

This page shows how to mount an NFS file share as a volume in Cloud Run. You can use any NFS server, including your own NFS server hosted on-premises, or on a Compute Engine VM. If you don't already have an NFS server, we recommend Filestore, which is a fully managed NFS offering from Google Cloud.

If you are looking to use NBD, 9P, CIFS/Samba, and Ceph network file systems refer to using NBD, 9P, CIFS/Samba, and Ceph network file systems.

Mounting the NFS file share as a volume in Cloud Run presents the file share as files in the container file system. After you you mount the file share as a volume, you access it as if it were a directory on your local file system, using your programming language's file system operations and libraries.

Disallowed paths

Cloud Run does not allow you to mount a volume at /dev, /proc and /sys, or on their subdirectories.

Limitations

In order to write to an NFS volume, your container must run as root. If your container only reads from the file system, it can run as any user.
Cloud Run does not support NFS locking. NFS volumes are automatically mounted in no-lock mode.

Before you begin

To mount an NFS server as a volume in Cloud Run, make sure you have the following:

A VPC Network where your NFS server or Filestore instance is running.
An NFS server running in a VPC network, with your Cloud Run service connected to that VPC network. If you don't already have an NFS server, create one by creating a Filestore instance.
Your Cloud Run service is attached to the VPC network where your NFS server is running. For best performance, use Direct VPC rather than VPC Connectors.
If you're using an existing project, make sure that your VPC Firewall configuration allows Cloud Run to reach your NFS server. (If you're starting from a new project, this is true by default.) If you're using Filestore as your NFS server, follow the Filestore documentation to create a Firewall egress rule to enable Cloud Run to reach Filestore.

Mount an NFS volume

You can mount multiple NFS servers, Filestore instances, or other volume types at different mount paths.

If you are using multiple containers, first specify the volume(s), then specify the volume mount(s) for each container.

Command line

Note: We show the gcloud beta run services update command but you can also use the gcloud beta run services deploy command with the same parameters as shown.

To add a volume and mount it:

gcloud beta run services update SERVICE \
--add-volume=name=VOLUME_NAME,type=nfs,location=IP_ADDRESS:NFS_PATH \
--add-volume-mount=volume=VOLUME_NAME,mount-path=MOUNT_PATH

Replace:

SERVICE with the name of your service.
VOLUME_NAME with the name you want to give your volume.
IP_ADDRESS with the location of the NFS file share.
NFS_PATH with the path to the NFS file share starting with a forward slash, for example /example-directory.
MOUNT_PATH with the relative path where you are mounting the volume, for example, /mnt/my-volume.
VOLUME_NAME with any name you want for your volume. The VOLUME_NAME value is used to map the volume to the volume mount.

To mount your volume as a read-only volume:

--add-volume=name=VOLUME_NAME,type=nfs,location=IP_ADDRESS:NFS_PATH,readonly=true

If you are using multiple containers, first specify the volumes, then specify the volume mounts for each container:

gcloud beta run services update SERVICE \
--add-volume=name VOLUME_NAME,type=nfs,location=IP_ADDRESS:NFS_PATH \
--container CONTAINER_1 \
--add-volume-mount volume=VOLUME_NAME,mount-path=MOUNT_PATH \
--container CONTAINER_2 \
--add-volume-mount volume= VOLUME_NAME,mount-path=MOUNT_PATH2

YAML

If you are creating a new service, skip this step. If you are updating an existing service, download its YAML configuration:
```
gcloud run services describe SERVICE --format export > service.yaml
```
Update the MOUNT_PATH, VOLUME_NAME, IP_ADDRESS, and NFS_PATH as needed. If you have multiple volume mounts, you will have multiples of these attributes.
```
apiVersion: run.googleapis.com/v1
kind: Service
metadata:
  name: SERVICE
    annotations:
      run.googleapis.com/launch-stage: BETA
spec:
  template:
    metadata:
      annotations:
        run.googleapis.com/execution-environment: gen2
    spec:
      containers:
      - image: IMAGE_URL
        volumeMounts:
        - name: VOLUME_NAME
          mountPath: MOUNT_PATH
      volumes:
      - name: VOLUME_NAME
        nfs:
          server: IP_ADDRESS
          path: NFS_PATH
          readOnly: IS_READ_ONLY
```
Replace
- SERVICE with the name of your Cloud Run service
- MOUNT_PATH with the relative path where you are mounting the volume, for example, /mnt/my-volume.
- VOLUME_NAME with any name you want for your volume. The VOLUME_NAME value is used to map the volume to the volume mount.
- IP_ADDRESS with the address of the NFS file share.
- NFS_PATH with the path to the NFS file share starting with a forward slash, for example, /example-directory.
- IS_READ_ONLY with True to make the volume read-only, or False to allow writes.
Replace the service with its new configuration using the following command:
```
gcloud beta run services replace service.yaml
```

Reading and writing to a volume

If you use the Cloud Run volume mount feature, you access a mounted volume using the same libraries in your programming language that you use to read and write files on your local file system.

This is especially useful if you're using an existing container that expects data to be stored on the local file system and uses regular file system operations to access it.

The following snippets assume a volume mount with a mountPath set to /mnt/my-volume.

Nodejs

Use the File System module to create a new file or append to an existing in the volume, /mnt/my-volume:

var fs = require('fs');
fs.appendFileSync('/mnt/my-volume/sample-logfile.txt', 'Hello logs!', { flag: 'a+' });

Python

Write to a file kept in the volume, /mnt/my-volume:

f = open("/mnt/my-volume/sample-logfile.txt", "a")

Go

Use the os package to create a new file kept in the volume, /mnt/my-volume

f, err := os.Create("/mnt/my-volume/sample-logfile.txt")

Java

Use the Java.io.File class to create a log file in the volume, /mnt/my-volume:

import java.io.File;
File f = new File("/mnt/my-volume/sample-logfile.txt");

Troubleshooting NFS

If you experience problems, check the following:

Your Cloud Run service is connected to the VPC network that the NFS server is on.
There are no firewall rules preventing Cloud Run from reaching the NFS server.
If your container writes to your NFS server, make sure it is running as root.