Installing a Docker Registry Cache on your Raspberry Pi

In this example - our local Raspberry Pi has the IP address 192.168.1.194

On your Pi – First install ‘Go version 1.8’ -

cd ~

wget https://storage.googleapis.com/golang/go1.8.linux-armv6l.tar.gz \

tar -C /usr/local -xzf go1.8.linux-armv6l.tar.gz

export PATH=$PATH:/usr/local/go/bin

Now Clone, build and install the Docker Registry project

git clone https://github.com/docker/distribution.git

cd distribution

go get ./...

GOOS=linux GOARCH=arm make binaries

After making the binaries – you should issue the command

ls bin/

and you should see files: digest, registry, registry‑api‑descriptor‑template

Before running the service you need to set up a config file to tell the registry service where to put images and to tell it to behave as a proxy for the main Docker repos images (nginx:latest, httpd:alpine etc) .

Create ~/distribution/bin/registry-config.yml and copy the following content into it:

version: 0.1

storage:

  cache:

    blobdescriptor: inmemory

  filesystem:

    rootdirectory: /var/lib/registry

http:

  addr: :5000

proxy:

 remoteurl: https://registry-1.docker.io

Create ~/distribution/bin/registry-config.yml and copy the following content into it:

Finally make a directory to store the images on your Pi

sudo mkdir ‑p /var/lib/registry

sudo chown $USER /var/lib/registry

Finally start up your Registry Server.

cd ~/distribution/bin/

./registry serve ~/registry‑config.yml

On your Desktop/Laptop (Docker Client)

Under the Docker Preferences setup your PI server as a

‘Registry Mirror’

Apply and Restart your Docker Application

Testing

On your Docker client desktop/laptop – open up a browser and after making sure you’re on the same subnet as your Pi – go to the location

http://192.168.1.194:5000/v2

You should notice the empty ‘{ }’ JSON response on your browser.

If you have a shell open where your Pi is running the service – you’ll notice the response.

Now let’s pull some images from the main Docker Repo.

Using a terminal – on your Client machine (Desktop or Laptop)

Issue the following commands

docker image rm hello-world  

Don’t worry if you get an error on this command.

docker image pull hello-world

When the client starts to pull the image – you should notice DEBUG information on your Pi terminal – indicating that the image is being cached on its system.

After the ‘pull’ command has  been completed – issue another ‘rm command’

docker image rm hello-world  

And then another ‘pull’

docker image pull hello-world

On the Pi console – you will notice that the image is now being pulled from the local Pi directory rather than over the internet.

On your Docker Client machine (Desktop/Laptop) – issue the _catalog service on the browser (http://192.168.1.194:5000/v2/_catalog)

You should notice – a list of cached images stored on the Pi.

 

 Finally

On your Pi - you may want to bind mount /var/library/registry on a USB drive

sudo mount /dev/sda1 /var/lib/registry/ -o umask=000    

#sudo umount /var/lib/registry/