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The Pulsar proxy

The Pulsar proxy is an optional gateway that you can run in front of the brokers in a Pulsar cluster. We recommend running a Pulsar proxy in cases when direction connections between clients and Pulsar brokers are either infeasible, undesirable, or both, for example when running Pulsar in a cloud environment or on Kubernetes or an analogous platform.

Configuring the proxy

The proxy must have some way to find the addresses of the brokers of the cluster. You can do this by either configuring the proxy to connect directly to service discovery or by specifying a broker URL in the configuration.

Option 1: Using service discovery

Pulsar uses ZooKeeper for service discovery. To connect the proxy to ZooKeeper, specify the following in conf/proxy.conf.


If using service discovery, the network ACL must allow the proxy to talk to the ZooKeeper nodes on the zookeeper client port, which is usually 2181, and on the configuration store client port, which is 2184 by default. Opening the network ACLs means that if someone compromises a proxy, they have full access to ZooKeeper. For this reason, it is more secure to use broker URLs to configure the proxy.

Option 2: Using broker URLs

The more secure method of configuring the proxy is to specify a URL to connect to the brokers.

Authorization at the proxy requires access to ZooKeeper, so if you are using this broker URLs to connect to the brokers, Proxy level authorization should be disabled. Brokers will still authorize requests after the proxy forwards them.

You can configure the broker URLs in conf/proxy.conf as follows.


Or if using TLS:


The hostname in the URLs provided should be a DNS entry which points to multiple brokers or a Virtual IP which is backed by multiple broker IP addresses so that the proxy does not lose connectivity to the pulsar cluster if a single broker becomes unavailable.

The ports to connect to the brokers (6650 & 8080, or in the case of TLS, 6651 & 8443) should be open in the network ACLs.

Note that if you are not using functions, then functionWorkerWebServiceURL does not need to be configured.

Starting the proxy

To start the proxy:

$ cd /path/to/pulsar/directory
$ bin/pulsar proxy

You can run as many instances of the Pulsar proxy in a cluster as you would like.

Stopping the proxy

The Pulsar proxy runs by default in the foreground. To stop the proxy, simply stop the process in which it's running.

Proxy frontends

We recommend running the Pulsar proxy behind some kind of load-distributing frontend, such as an HAProxy load balancer.

Using Pulsar clients with the proxy

Once your Pulsar proxy is up and running, preferably behind a load-distributing frontend, clients can connect to the proxy via whichever address is used by the frontend. If the address were the DNS address pulsar.cluster.default, for example, then the connection URL for clients would be pulsar://pulsar.cluster.default:6650.

Proxy configuration

The Pulsar proxy can be configured using the proxy.conf configuration file. The following parameters are available in that file:

zookeeperServersThe ZooKeeper quorum connection string (as a comma-separated list)
configurationStoreServersConfiguration store connection string (as a comma-separated list)
zookeeperSessionTimeoutMsZooKeeper session timeout (in milliseconds)30000
servicePortThe port to use for server binary Protobuf requests6650
servicePortTlsThe port to use to server binary Protobuf TLS requests6651
statusFilePathPath for the file used to determine the rotation status for the proxy instance when responding to service discovery health checks
authenticationEnabledWhether authentication is enabled for the Pulsar proxyfalse
authenticationProvidersAuthentication provider name list (a comma-separated list of class names)
authorizationEnabledWhether authorization is enforced by the Pulsar proxyfalse
authorizationProviderAuthorization provider as a fully qualified class
brokerClientAuthenticationPluginThe authentication plugin used by the Pulsar proxy to authenticate with Pulsar brokers
brokerClientAuthenticationParametersThe authentication parameters used by the Pulsar proxy to authenticate with Pulsar brokers
brokerClientTrustCertsFilePathThe path to trusted certificates used by the Pulsar proxy to authenticate with Pulsar brokers
superUserRolesRole names that are treated as "super-users," meaning that they will be able to perform all admin
forwardAuthorizationCredentialsWhether client authorization credentials are forwarded to the broker for re-authorization. Authentication must be enabled via authenticationEnabled=true for this to take effect.false
maxConcurrentInboundConnectionsMax concurrent inbound connections. The proxy will reject requests beyond that.10000
maxConcurrentLookupRequestsMax concurrent outbound connections. The proxy will error out requests beyond that.50000
tlsEnabledInProxyWhether TLS is enabled for the proxyfalse
tlsEnabledWithBrokerWhether TLS is enabled when communicating with Pulsar brokersfalse
tlsCertificateFilePathPath for the TLS certificate file
tlsKeyFilePathPath for the TLS private key file
tlsTrustCertsFilePathPath for the trusted TLS certificate pem file
tlsHostnameVerificationEnabledWhether the hostname is validated when the proxy creates a TLS connection with brokersfalse
tlsRequireTrustedClientCertOnConnectWhether client certificates are required for TLS. Connections are rejected if the client certificate isn’t trusted.false