NGS Leaf Nodes

This mini-tutorial shows how to run 2 NATS server in local Docker containers interconnected via Synadia Cloud Platform. NGS is a global managed NATS network of NATS, and the local containers will connect to it as leaf nodes.

Start by creating a free account on https://cloud.synadia.com/.

Once you are logged in, go into the default account (you can manage multiple isolated NGS account within your Synadia Cloud account).

In Settings > Limits, increase Leaf Nodes to 2. Save the configuration change. (Your free account comes with up to 2 leaf connection, but the account is configured to use at most 1 initially).

Now navigate to the Users section of your default account and create 2 users, red and blue. (Users are another way you can isolate parts of your systems customizing permissions, access to data, limits and more)

For each of the two users, select Get Connected and Download Credentials.

You should now have 2 files on your computer: default-red.creds and default-blue.creds.

Create a minimal NATS Server configuration file leafnode.conf, it will work for both leaf nodes:

leafnodes {
    remotes = [
        {
          url: "tls://connect.ngs.global"
          credentials: "ngs.creds"
        },
    ]
}

Let's start the first leafnode (for user red) with:

docker run  -p 4222:4222 -v leafnode.conf:/leafnode.conf -v /etc/ssl/cert.pem:/etc/ssl/cert.pem -v default-red.creds:/ngs.creds  nats:latest -c /leafnode.conf

-p 4222:4222 maps the server port 4222 inside the container to your local port 4222. -v leafnode.conf:/leafnode.conf mounts the configuration file created above at location /leafnode.conf in the container. -v /etc/ssl/cert.pem:/etc/ssl/cert.pem installs root certificates in the container, since the nats image does not bundle them, and they are required to verify the TLS certificate presented by NGS. -v default-red.creds:/ngs.creds installs the credentials for user red at location /ngs.creds inside the container. -c /leafnode.conf are arguments passed to the container entry point (nats-server).

Launching the container, you should see the NATS server starting successfully:

[1] 2024/06/14 18:03:51.810719 [INF] Server is ready
[1] 2024/06/14 18:03:52.075951 [INF] 34.159.142.0:7422 - lid:5 - Leafnode connection created for account: $G
[1] 2024/06/14 18:03:52.331354 [INF] 34.159.142.0:7422 - lid:5 - JetStream using domains: local "", remote "ngs"

Now start the second leaf nodes with two minor tweaks to the command:

docker run  -p 4333:4222 -v leafnode.conf:/leafnode.conf -v /etc/ssl/cert.pem:/etc/ssl/cert.pem -v default-blue.creds:/ngs.creds  nats:latest -c /leafnode.conf

Notice we bind to local port 4333 (since 4222) is busy, and we mount blue credentials.

Congratulations, you have 2 leaf nodes connected to the NGS global network. Despite this being a global shared environment, your account is completely isolated from the rest of the traffic, and vice versa.

Now let's make 2 clients connected to the 2 leaf nodes talk to each other.

Let us start a simple service on the Leafnode of user red:

nats -s localhost:4222 reply docker-leaf-test "At {{Time}}, I received your request: {{Request}}"

Using the LeafNode run by user blue, let's send a request:

$ nats -s localhost:4333 request docker-leaf-test "Hello World"

At 8:15PM, I received your request: Hello World

Congratulations, you just connected 2 Leaf nodes to the global NGS network and used them to send a request and receive a response.

Your messages were routed transparently with millions of others, but they were not visible to anyone outside of your Synadia Cloud account.

Related and useful:

• Official Docker image for the NATS server on GitHub and issues
• nats images on DockerHub
• nats CLI tool and nats bench
• Leaf Nodes configuration