Deploying Dubbo Applications to Kubernetes Environments

Deploy Dubbo applications to Kubernetes environments, using Nacos or Zookeeper as the registry.

This model is not much different from traditional non-Kubernetes deployments. As shown in the picture below, Nacos or Zookeeper is still used as the registry, but Kubernetes is used as the underlying platform for application lifecycle scheduling.

Install Nacos

In Kubernetes mode, we recommend using dubboctl to quickly install components like Nacos, dubbo-control-plane, prometheus, etc.:

$ dubboctl install --profile=demo

Tip

1. Please refer to dubboctl for more details.
2. You can also check out the official Nacos installation plan for Kubernetes clusters.

Deploy Application

We still take the project in Quick Start as an example to demonstrate the specific steps for packaging and deploying the application.

First, clone the sample project locally:

$ git clone -b main --depth 1 https://github.com/apache/dubbo-samples

Switch to the example directory:

$ cd dubbo-samples/11-quickstart

Package Image

$ dubboctl build
# Specifically push to docker repository

Deploy

$ dubboctl deploy

Here are the generated complete Kubernetes manifests:

Run the following command to deploy the application to the Kubernetes cluster:

$ kubectl apply -f xxx.yml

Check Deployment Status

If you have previously installed dubbo-control-plane using dubboctl, you can check the service deployment status as follows:

$ kubectl port-forward

Access http://xxx to view the service deployment details.

Graceful Online/Offline

As shown in the architecture diagram above, we still use Nacos as the registry. Therefore, similar to traditional Linux deployment models, the timing of publishing instances to the registry and removing instances from the registry is key to achieving graceful online/offline:

1. Online phase, control when instances register to the registry using the delayed publishing mechanism, and ensure traffic is gradually directed to new nodes by enabling consumer-side warming.
2. Offline phase, configure prestop to ensure instance registration information is removed from the registry first, before proceeding to the process destruction phase.

Example configuration for gracefully offline removing instances:

preStop:
    exec:
      command: ["/bin/sh","-c","curl /offline; sleep 10"]

Tip

In this model, since the publishing and unpublishing of Dubbo services are strongly tied to the registry, they do not correlate much with liveness and readiness in Kubernetes. In the next document, we will discuss how to configure liveness and readiness in Kubernetes Service deployment mode.

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Last modified November 7, 2024: fix multi-protocols docs (#3058) (de52c77177a)