Migrate Pulsar Functions

Pulsar supports submitting Pulsar Functions to a Kubernetes cluster through the Functions worker. But, Pulsar only supports launching and tracking them manually one by one. However, Function Mesh supports submitting and managing a bundle of Pulsar Function, which reduces the management and operation efforts.

If you have run Pulsar Functions in a Kubernetes cluster and want to migrate them to Function Mesh, Function Mesh provides you a tool, which is used to migrate Pulsar Functions from the function worker of a Pulsar cluster to Function Mesh. To transfer Pulsar cluster configurations, this tool encapsulates the pulsarctl configurations.

This document describes how to build the tool from the source code and how to use the tool to migrate Pulsar Functions from an existing cluster to Function Mesh.

Note

Currently, this migration tool is a beta version.

Prerequisites

• Go 1.15 or higher

Steps

1. Build the tool.

   1. Define a pulsarctl.properties configuration file for the tool.

      webServiceUrl=http://localhost:8080
      tlsAllowInsecureConnection=false
      tlsTrustCertsFilePath=
      brokerServiceUrl=
      authParams=
      authPlugin=
      tlsEnableHostnameVerification=false

   2. Declare environment variables PULSAR_CLIENT_CONF.

      export PULSAR_CLIENT_CONF=/PATH/pulsarctl.properties

      Replace the PATH variable with the absolute path to the pulsarctl.properties configuration file.

   3. Build the tool from the source code.

      git clone https://github.com/streamnative/function-mesh
      cd function-mesh/tools
      go build

2. Generate the YAML file which is used to create the function in Function Mesh.

   ./tools

   The generated YAML file adopts a structure as below, where the public, default, and function-sample represent the tenant name, namespace name, and function name respectively.

   functions
   └── public
       └── default
           └── function-sample.yaml

   This is an example of the generated YAML file.

   ```yaml
   apiVersion: compute.functionmesh.io/v1alpha1
   kind: Function
   metadata:
     creationTimestamp: null
     name: function-sample
     namespace: default
   spec:
     autoAck: true
     className: exclamation_function.ExclamationFunction
     cleanupSubscription: true
     clusterName: standalone
     funcConfig:
       PublishTopic: test_result
     input:
       sourceSpecs:
       test_src: {}
       topics:
       - test_src
     # other function config
   ```

After the YAML file is generated, you can use the kubectl apply -f command to create the function.

kubectl apply -f /path/to/function-sample.yaml