Speed up docker using NFS volumes

Docker For Mac runs the docker server within the virtual machine. The host machine shares the file system with the VM using osxfs. According to the documentation:

I have an application I want to run within Docker. It has some special dependencies I don’t want to install on my host machine. The docker-compose.yml definition looks as follows:

version: '3'

services:
    php-fpm:
        build:
            context: .
            dockerfile: .docker/php/Dockerfile
        volumes:
            - ./project:/app
            - .docker/php/php.ini:/usr/local/etc/php/php.ini:ro
    nginx:
        image: nginx:latest
        ports:
            - "8080:80"
        volumes:
            - ./project:/app
            - .docker/nginx/default.conf:/etc/nginx/conf.d/default.conf:ro

Docker for Mac allows you to use a special configuration option for volumes to improve the performance. By default, Docker mounts each volume using a consistent option. It means, that everything you see on the host machine is the same as in the container.

version: '3'

services:
    php-fpm:
        build:
            context: .
            dockerfile: .docker/php/Dockerfile
        volumes:
            - ./project:/app:delegated
            - .docker/php/php.ini:/usr/local/etc/php/php.ini:ro
    nginx:
        image: nginx:latest
        ports:
            - "8080:80"
        volumes:
            - ./project:/app:delegated
            - .docker/nginx/default.conf:/etc/nginx/conf.d/default.conf:ro

If you want to mount volumes from NFS, you need to expose selected directories in /etc/export file. Some people export the entire home directory, however, I prefer to limit the scope of what is accessible from NFS only to data I need.

#!/usr/bin/env bash

OS=`uname -s`

if [ $OS != "Darwin" ]; then
  echo "This script is OSX-only. Please do not run it on any other Unix."
  exit 1
fi

if [[ $EUID -eq 0 ]]; then
  echo "This script must NOT be run with sudo/root. Please re-run without sudo." 1>&2
  exit 1
fi

echo ""
echo " +-----------------------------+"
echo " | Setup native NFS for Docker |"
echo " +-----------------------------+"
echo ""

echo "WARNING: This script will shut down running containers."
echo ""
echo -n "Do you wish to proceed? [y]: "
read decision

if [ "$decision" != "y" ]; then
  echo "Exiting. No changes made."
  exit 1
fi

echo ""

if ! docker ps > /dev/null 2>&1 ; then
  echo "== Waiting for docker to start..."
fi

open -a Docker

while ! docker ps > /dev/null 2>&1 ; do sleep 2; done

echo "== Stopping running docker containers..."
docker-compose down > /dev/null 2>&1
docker volume prune -f > /dev/null

osascript -e 'quit app "Docker"'

echo "== Resetting folder permissions..."
U=`id -u`
G=`id -g`
sudo chown -R "$U":"$G" .

echo "== Setting up nfs..."
{ZAZNACZ TE LINIE} LINE="/Volumes/Work -alldirs -mapall=$U:$G localhost"
FILE=/etc/exports
sudo cp /dev/null $FILE
grep -qF -- "$LINE" "$FILE" || sudo echo "$LINE" | sudo tee -a $FILE > /dev/null

LINE="nfs.server.mount.require_resv_port = 0"
FILE=/etc/nfs.conf
grep -qF -- "$LINE" "$FILE" || sudo echo "$LINE" | sudo tee -a $FILE > /dev/null

echo "== Restarting nfsd..."
sudo nfsd restart

echo "== Restarting docker..."
open -a Docker

while ! docker ps > /dev/null 2>&1 ; do sleep 2; done

echo ""
echo "SUCCESS! Now go run your containers 🐳"

If you want to export the whole home directory, you can change this line to /Users. If you use a macOS 10.15 (Catalina), the path to the home directory is different because Apple separated Data volume from System Volume (they made system data read-only) and it looks as follows:

/System/Volumes/Data/Users

LINE="/System/Volumes/Data/Users -alldirs -mapall=$U:$G localhost"

Save this script, e.g. in your project directory, e.g. as setup_nfs_docker.sh, make it executable and run.

> sudo chmod +x setup_nfs_docker.sh
> ./setup_nfs_docker.sh

Once the NFS server was configured and started, you should be able to connect to it using the Finder. Select Go > Connect to Server... option from the menu and try to connect to your local server.

It’s time to change the definition of docker-compose.yml. Open this file in your editor, add the volume section and use the newly defined volume in containers.

version: '3'

services:
    php-fpm:
        build:
            context: .
            dockerfile: .docker/php/Dockerfile
        volumes:
            - nfsmount:/app
            - .docker/php/php.ini:/usr/local/etc/php/php.ini:ro
    nginx:
        image: nginx:latest
        ports:
            - "8080:80"
        volumes:
            - nfsmount:/app
            - .docker/nginx/default.conf:/etc/nginx/conf.d/default.conf:ro
            
volumes:
    nfsmount:
                driver: local
        driver_opts:
            type: nfs
            o: addr=host.docker.internal,rw,nolock,hard,nointr,nfsvers=3
            device: ":${PWD}"

Using the delegated option has a big impact on the performance, however, it also has some caveats and you should be aware of them before you decide to use this option.

The app running on NFS volume has slightly better performance than the app running on a volume mounted with a delegated option. In some cases, it may speed up the application by seconds, leverage the overall developer experience to the satisfying level.

Please also be aware that osxfs file system (on both consisted and delegated option) supports the file system events. NFS volumes don’t have this functionality, so if you depend on it, NFS isn’t the right choice.

It’s hard to say, but Docker For Mac has still some basic performance-related problems. By tuning configuration a bit (e.g. using delegated option), we can achieve better speeds, but it’s still far away from the native-feel that Linux offers without any hassle.