The Pulsar proxy

Pulsar代理是一个可选的网关，你可以在Pulsar集群中的brokers之前运行它们。 You can run a Pulsar proxy in cases when direction connections between clients and Pulsar brokers are either infeasible, undesirable, or both, for example when you run Pulsar in a cloud environment or on Kubernetes or an analogous platform.

配置Proxy

Proxy 有办法来找到集群中 broker 的地址。 你可以通过配置代理来直接连接到服务发现，或者在配置中指定broker URL。

Option 1: Use service discovery

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

zookeeperServers=zk-0,zk-1,zk-2
configurationStoreServers=zk-0:2184,zk-remote:2184

If you use 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. 打开网络ACLs意味着如果有人破坏了代理，那么他们可以完全访问ZooKeeper。 For this reason, using broker URLs to configure the proxy is more secure.

Option 2: Use broker URLs

配置代理的更安全的方法是指定连接到brokers的URL。

Authorization at the proxy requires access to ZooKeeper, so if you use these broker URLs to connect to the brokers, you should disable the Proxy level authorization. Brokers still authorize requests after the proxy forwards them.

您可以在 conf/proxy.conf中配置broker URLs，如下所示。

brokerServiceURL=pulsar://brokers.example.com:6650
brokerWebServiceURL=http://brokers.example.com:8080
functionWorkerWebServiceURL=http://function-workers.example.com:8080

Or if you use TLS:

brokerServiceURLTLS=pulsar+ssl://brokers.example.com:6651
brokerWebServiceURLTLS=https://brokers.example.com:8443
functionWorkerWebServiceURL=https://function-workers.example.com:8443

提供的URLs中的主机名应该是指向多个 broker 的DNS条目，或由多个broker 的IP地址支持的虚拟IP，以便在单个 broker 不可用时 ，代理不会失去与 Pulsar 群集的连接。

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

Note that if you do not use functions, then you do not need to configure functionWorkerWebServiceURL.

启动 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 want.

停止 Proxy

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

Proxy frontends

You can run the Pulsar proxy behind some kind of load-distributing frontend, such as an HAProxy load balancer.

Pulsar 客户端连接 Proxy

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

Proxy configuration

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