Kafka Broker filter

The Apache Kafka broker filter decodes the client protocol for Apache Kafka, both the requests and responses in the payload. The message versions in Kafka 2.4.0 are supported. The filter attempts not to influence the communication between client and brokers, so the messages that could not be decoded (due to Kafka client or broker running a newer version than supported by this filter) are forwarded as-is.

• v2 API reference

• This filter should be configured with the name envoy.filters.network.kafka_broker.

Attention

The kafka_broker filter is experimental and is currently under active development. Capabilities will be expanded over time and the configuration structures are likely to change.

Configuration

The Kafka Broker filter should be chained with the TCP proxy filter as shown in the configuration snippet below:

listeners:
- address:
    socket_address:
      address: 127.0.0.1 # Host that Kafka clients should connect to.
      port_value: 19092  # Port that Kafka clients should connect to.
  filter_chains:
  - filters:
    - name: envoy.filters.network.kafka_broker
      typed_config:
        "@type": type.googleapis.com/envoy.config.filter.network.kafka_broker.v2alpha1.KafkaBroker
        stat_prefix: exampleprefix
    - name: envoy.filters.network.tcp_proxy
      typed_config:
        "@type": type.googleapis.com/envoy.config.filter.network.tcp_proxy.v2.TcpProxy
        stat_prefix: tcp
        cluster: localkafka
clusters:
- name: localkafka
  connect_timeout: 0.25s
  type: strict_dns
  lb_policy: round_robin
  hosts:
  - socket_address:
      address: 127.0.0.1 # Kafka broker's host.
      port_value: 9092   # Kafka broker's port.

The Kafka broker needs to advertise the Envoy listener port instead of its own.

# Listener value needs to be equal to cluster value in Envoy config
# (will receive payloads from Envoy).
listeners=PLAINTEXT://127.0.0.1:9092
# Advertised listener value needs to be equal to Envoy's listener
# (will make clients discovering this broker talk to it through Envoy).
advertised.listeners=PLAINTEXT://127.0.0.1:19092

Statistics

Every configured Kafka Broker filter has statistics rooted at kafka.<stat_prefix>., with multiple statistics per message type.