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Deploy and manage functions worker

Before using Pulsar Functions, you need to learn how to set up Pulsar Functions worker and how to configure Functions runtime.

Pulsar functions-worker is a logic component to run Pulsar Functions in cluster mode. Two options are available, and you can select either based on your requirements.


The --- Service Urls--- lines in the following diagrams represent Pulsar service URLs that Pulsar client and admin use to connect to a Pulsar cluster.

Run Functions-worker with brokers

The following diagram illustrates the deployment of functions-workers running along with brokers.


To enable functions-worker running as part of a broker, you need to set functionsWorkerEnabled to true in the broker.conf file.


If the functionsWorkerEnabled is set to true, the functions-worker is started as part of a broker. You need to configure the conf/functions_worker.yml file to customize your functions_worker.

Before you run Functions-worker with broker, you have to configure Functions-worker, and then start it with brokers.

Configure Functions-Worker to run with brokers

In this mode, most of the settings are already inherited from your broker configuration (for example, configurationStore settings, authentication settings, and so on) since functions-worker is running as part of the broker.

Pay attention to the following required settings when configuring functions-worker in this mode.

  • numFunctionPackageReplicas: The number of replicas to store function packages. The default value is 1, which is good for standalone deployment. For production deployment, to ensure high availability, set it to be larger than 2.
  • initializedDlogMetadata: Whether to initialize distributed log metadata in runtime. If it is set to true, you must ensure that it has been initialized by bin/pulsar initialize-cluster-metadata command.

If authentication is enabled on the BookKeeper cluster, configure the following BookKeeper authentication settings.

  • bookkeeperClientAuthenticationPlugin: the BookKeeper client authentication plugin name.
  • bookkeeperClientAuthenticationParametersName: the BookKeeper client authentication plugin parameters name.
  • bookkeeperClientAuthenticationParameters: the BookKeeper client authentication plugin parameters.

Configure Stateful-Functions to run with broker

If you want to use Stateful-Functions related functions (for example, putState() and queryState() related interfaces), follow steps below.

  1. Enable the streamStorage service in the BookKeeper.

    Currently, the service uses the NAR package, so you need to set the configuration in bookkeeper.conf.

    After starting bookie, use the following methods to check whether the streamStorage service is started correctly.


    telnet localhost 4181


    Connected to localhost.
    Escape character is '^]'.

  2. Turn on this function in functions_worker.yml.

    stateStorageServiceUrl: bk://<bk-service-url>:4181

    bk-service-url is the service URL pointing to the BookKeeper table service.

Start Functions-worker with broker

Once you have configured the functions_worker.yml file, you can start or restart your broker.

And then you can use the following command to verify if functions-worker is running well.

curl <broker-ip>:8080/admin/v2/worker/cluster

After entering the command above, a list of active function workers in the cluster is returned. The output is similar to the following.


Run Functions-worker separately

This section illustrates how to run functions-worker as a separate process in separate machines.



In this mode, make sure functionsWorkerEnabled is set to false, so you won't start functions-worker with brokers by mistake. Also, while accessing the functions-worker to manage any of the functions, the pulsar-admin CLI tool or any of the clients should use the workerHostname and workerPort that you set in Worker parameters to generate an --admin-url.

Configure Functions-worker to run separately

To run function-worker separately, you have to configure the following parameters.

Worker parameters

  • workerId: The type is string. It is unique across clusters, which is used to identify a worker machine.
  • workerHostname: The hostname of the worker machine.
  • workerPort: The port that the worker server listens on. Keep it as default if you don't customize it.
  • workerPortTls: The TLS port that the worker server listens on. Keep it as default if you don't customize it.

Function package parameter

  • numFunctionPackageReplicas: The number of replicas to store function packages. The default value is 1.

Function metadata parameter

  • pulsarServiceUrl: The Pulsar service URL for your broker cluster.
  • pulsarWebServiceUrl: The Pulsar web service URL for your broker cluster.
  • pulsarFunctionsCluster: Set the value to your Pulsar cluster name (same as the clusterName setting in the broker configuration).

If authentication is enabled for your broker cluster, you should configure the authentication plugin and parameters for the functions worker to communicate with the brokers.

  • clientAuthenticationPlugin
  • clientAuthenticationParameters

Customize Java runtime options

If you want to pass additional arguments to the JVM command line to every process started by a function worker, you can configure the additionalJavaRuntimeArguments parameter.

additionalJavaRuntimeArguments: ['-XX:+ExitOnOutOfMemoryError','-Dfoo=bar']

This is very useful in case you want to:

  • add JMV flags, like -XX:+ExitOnOutOfMemoryError
  • pass custom system properties, like -Dlog4j2.formatMsgNoLookups

This feature applies only to Process and Kubernetes runtimes.

Security settings

If you want to enable security on functions workers, you should:

Enable TLS transport encryption

To enable TLS transport encryption, configure the following settings.

useTLS: true
pulsarServiceUrl: pulsar+ssl://localhost:6651/
pulsarWebServiceUrl: https://localhost:8443

tlsEnabled: true
tlsCertificateFilePath: /path/to/functions-worker.cert.pem
tlsKeyFilePath: /path/to/functions-worker.key-pk8.pem
tlsTrustCertsFilePath: /path/to/ca.cert.pem

// The path to trusted certificates used by the Pulsar client to authenticate with Pulsar brokers
brokerClientTrustCertsFilePath: /path/to/ca.cert.pem

For details on TLS encryption, refer to Transport Encryption using TLS.

Enable Authentication Provider

To enable authentication on Functions Worker, you need to configure the following settings.


Substitute the providers list with the providers you want to enable.

authenticationEnabled: true
authenticationProviders: [ provider1, provider2 ]

For TLS Authentication provider, follow the example below to add the necessary settings. See TLS Authentication for more details.

brokerClientAuthenticationPlugin: org.apache.pulsar.client.impl.auth.AuthenticationTls
brokerClientAuthenticationParameters: tlsCertFile:/path/to/admin.cert.pem,tlsKeyFile:/path/to/admin.key-pk8.pem

authenticationEnabled: true
authenticationProviders: ['']

For SASL Authentication provider, add saslJaasClientAllowedIds and saslJaasBrokerSectionName under properties if needed.

saslJaasClientAllowedIds: .*pulsar.*
saslJaasBrokerSectionName: Broker

For Token Authentication provider, add necessary settings for properties if needed. See Token Authentication for more details. Note: key files must be DER-encoded

tokenSecretKey: file://my/secret.key
# If using public/private
# tokenPublicKey: file:///path/to/public.key

Enable Authorization Provider

To enable authorization on Functions Worker, you need to configure authorizationEnabled, authorizationProvider and configurationMetadataStoreUrl. The authentication provider connects to configurationMetadataStoreUrl to receive namespace policies.

authorizationEnabled: true
configurationMetadataStoreUrl: <meta-type>:<configuration-metadata-store-url>

You should also configure a list of superuser roles. The superuser roles are able to access any admin API. The following is a configuration example.

- role1
- role2
- role3

Enable End-to-End Encryption

You can use the public and private key pair that the application configures to perform encryption. Only the consumers with a valid key can decrypt the encrypted messages.

To enable End-to-End encryption on Functions Worker, you can set it by specifying --producer-config in the command line terminal, for more information, please refer to here.

We include the relevant configuration information of CryptoConfig into ProducerConfig. The specific configurable field information about CryptoConfig is as follows:

public class CryptoConfig {
private String cryptoKeyReaderClassName;
private Map<String, Object> cryptoKeyReaderConfig;

private String[] encryptionKeys;
private ProducerCryptoFailureAction producerCryptoFailureAction;

private ConsumerCryptoFailureAction consumerCryptoFailureAction;

  • producerCryptoFailureAction: define the action if producer fail to encrypt data one of FAIL, SEND.
  • consumerCryptoFailureAction: define the action if consumer fail to decrypt data one of FAIL, DISCARD, CONSUME.

BookKeeper Authentication

If authentication is enabled on the BookKeeper cluster, you need configure the BookKeeper authentication settings as follows:

  • bookkeeperClientAuthenticationPlugin: the plugin name of BookKeeper client authentication.
  • bookkeeperClientAuthenticationParametersName: the plugin parameters name of BookKeeper client authentication.
  • bookkeeperClientAuthenticationParameters: the plugin parameters of BookKeeper client authentication.

Start Functions-worker

Once you have finished configuring the functions_worker.yml configuration file, you can start a functions-worker in the background by using nohup with the pulsar-daemon CLI tool:

bin/pulsar-daemon start functions-worker

You can also start functions-worker in the foreground by using pulsar CLI tool:

bin/pulsar functions-worker

Configure Proxies for Functions-workers

When you are running functions-worker in a separate cluster, the admin rest endpoints are split into two clusters. functions, function-worker, source and sink endpoints are now served by the functions-worker cluster, while all the other remaining endpoints are served by the broker cluster. Hence you need to configure your pulsar-admin to use the right service URL accordingly.

In order to address this inconvenience, you can start a proxy cluster for routing the admin rest requests accordingly. Hence you will have one central entry point for your admin service.

If you already have a proxy cluster, continue reading. If you haven't setup a proxy cluster before, you can follow the instructions to start proxies.


To enable routing functions related admin requests to functions-worker in a proxy, you can edit the proxy.conf file to modify the following settings:


Compare the Run-with-Broker and Run-separately modes

As described above, you can run Function-worker with brokers, or run it separately. And it is more convenient to run functions-workers along with brokers. However, running functions-workers in a separate cluster provides better resource isolation for running functions in Process or Thread mode.

Use which mode for your cases, refer to the following guidelines to determine.

Use the Run-with-Broker mode in the following cases:

  • a) if resource isolation is not required when running functions in Process or Thread mode;
  • b) if you configure the functions-worker to run functions on Kubernetes (where the resource isolation problem is addressed by Kubernetes).

Use the Run-separately mode in the following cases:

  • a) you don't have a Kubernetes cluster;
  • b) if you want to run functions and brokers separately.


Error message: Namespace missing local cluster name in clusters list

Failed to get partitioned topic metadata: org.apache.pulsar.client.api.PulsarClientException$BrokerMetadataException: Namespace missing local cluster name in clusters list: local_cluster=xyz ns=public/functions clusters=[standalone]

The error message prompts when either of the cases occurs:

  • a) a broker is started with functionsWorkerEnabled=true, but the pulsarFunctionsCluster is not set to the correct cluster in the conf/functions_worker.yaml file;
  • b) setting up a geo-replicated Pulsar cluster with functionsWorkerEnabled=true, while brokers in one cluster run well, brokers in the other cluster do not work well.


If any of these cases happens, follow the instructions below to fix the problem:

  1. Disable Functions Worker by setting functionsWorkerEnabled=false, and restart brokers.

  2. Get the current clusters list of public/functions namespace.

bin/pulsar-admin namespaces get-clusters public/functions

  1. Check if the cluster is in the clusters list. If the cluster is not in the list, add it to the list and update the clusters list.

bin/pulsar-admin namespaces set-clusters --clusters <existing-clusters>,<new-cluster> public/functions

  1. After setting the cluster successfully, enable functions worker by setting functionsWorkerEnabled=true.

  2. Set the correct cluster name in pulsarFunctionsCluster in the conf/functions_worker.yml file, and restart brokers.