Kubernetes, NodeJS and gRPC

[Sharan Karthikeyan]

I have created a headless service in kubernetes for gRPC server. But, I'm not able to connect that server in NodeJS client the connection url like this "bbl-org-server.default.svc.cluster.local" -- "<serviceName>.<namespace>.svc.cluster.local". Please help me.

Regards,

Sharan

[Richard Belleville]

Can you please provide more context? Your headless service should create a DNS entry in kubedns as you've described and the kubernetes NodeJS client should be able to resolve that DNS entry. Exactly what is the issue you are experiencing? 

[Sharan Karthikeyan]

Actually, I found the answer. I have used the localhost socket in the gRPC server, I changed it 0.0.0.0:PORT, and then it worked.
Thank you for the response.

[Keyur Patel]

Hi @sharan,
Can you share your yaml files example? I am facing the same issue.

[Keyur Patel]

// Server.yaml

// Client.yaml

// Service.yaml

[Sharan Karthikeyan]

Can you please share your client listening port and IP address?
If you are using 127.0.0.1 (localhost), then change it to 0.0.0.0:PORT

[Sharan Karthikeyan]

Make sure gRPC server running on 0.0.0.0:PORT, so you have to make the connection to that socket from your client side. If you are using localhost:PORT in client side, it is pointing to the current pod's (client side - local machine) socket, hence you need change 0.0.0.0:PORT in both gRPC side (server) as well as your client side (Node or Apache or Go or etc).

[Keyur Patel]

I am using this on the client side: "<serviceName>.<namespace>.svc.cluster.local:80". 

[Sharan Karthikeyan]

I will give a step-by-step approach to solving this problem.

1. You have a gRPC server. Make sure it is running on the "0.0.0.0:PORT" socket. And, make a cluster IP service to this gRPC pod. Assume we named it "grpc_service".

2. Assume you have Node JS (REST API - CLIENT) listening on the Kubernetes service of your gRPC. ``config.OG_GRPC_SERVER = "grpc_service:PORT"

If you do this, you will not need the "<serviceName>.<namespace>.svc.cluster.local:80" connection URL. I can you are facing an issue with connection in client.

[Sharan Karthikeyan]

Please share your client connection file and the gRPC server connection file.

[Keyur Patel]

Hi @sharan,
Thanks for sharing the details. I am using the same Nodejs server & client. Let me try this client configuration. 
Are you creating a headless service and adding a DNS entry in kubedns?


Here is my server & client files:

// Server.ts
...imports

const gRPCPort = config.GRPC_SERVER_PORT;

const options: protoLoader.Options = {

keepCase: true,

longs: String,

enums: String,

defaults: true,

arrays: true,

oneofs: true,

};

const PROTO_FILE = '../proto/xyz.service.proto';

const packageDef = protoLoader.loadSync(

path.resolve(__dirname, PROTO_FILE),

options,

);

const proto = loadPackageDefinition(packageDef) as unknown as ProtoGrpcType;

const server = new Server();

// XYZ Services

server.addService(proto.xyz.xyzService.service, {

GetABC: (req, res) => getABCHandler(req, res),

} as XyzServiceHandlers);

server.bindAsync(

`0.0.0.0:${gRPCPort}`,

ServerCredentials.createInsecure(),

(err, port) => {

if (err) {

throw err;

}

console.log(`gRPC server listening on ${port}`);

server.start();

},

);

// Client.ts

const gRPCPort = config.GRPC_SERVER_PORT;

export const client = new proto.xyz.xyzService(

`0.0.0.0:${gRPCPort}`,

credentials.createInsecure()

);

const deadline = new Date();

deadline.setSeconds(deadline.getSeconds() + 1);

client.waitForReady(deadline, (err) => {

if (err) {

console.error(err);

return;

}

onClientReady();

});

function onClientReady() {

console.log("? gRPC Client is ready");

}

[Keyur Patel]

Hi @sharan,
Thank you so much man. "service_name:PORT" worked. 

[Sharan Karthikeyan]

Great!!