Consumer DNS Ayarları

Giriş

Açıklaması şöyle. Yani consumer broker'ları bulmak için normalde işletim sisteminin varsayılan DNS ayarlarını kullanır

When a Kafka client is started, it first reads its configuration file to determine the initial list of bootstrap brokers. These brokers are specified as a comma-separated list of hostname and port pairs (e.g., broker1.example.com:9092,broker2.example.com:9092).

The Kafka client then performs DNS resolution to obtain the IP addresses of the specified hostnames. By default, the client uses the operating system’s default DNS resolution behavior, which typically involves sending DNS queries to a DNS resolver provided by the operating system.

client.dns.lookup Alanı

Varsayılan DNS ayarlarını değiştirmek istersek client.dns.lookup alanına değer atanır. Değerler şöyle

1. default

Açıklaması şöyle. 

This is the default value, which means that the Kafka client will use the default DNS resolution behavior of the operating system.

2. use_all_dns_ips

Açıklaması şöyle. 

This value causes the Kafka client to resolve all IP addresses returned by the DNS lookup and use them in a round-robin fashion. This can be useful in cases where you have multiple IP addresses associated with a hostname and want to distribute the load across all of them.

3. resolve_canonical_bootstrap_servers_only

Açıklaması şöyle. 

This value causes the Kafka client to resolve only the canonical hostname of the bootstrap servers, rather than resolving all the hostnames returned by the initial DNS lookup. This can be useful in cases where you have multiple DNS entries for the same Kafka cluster, but only one of them is the canonical hostname. When enabled, once a hostname has been resolved, the client will do a reverse lookup to find the FQDN. This can be required in some cases when using SASL GSSAPI.

4. prefer_ipv4

Açıklaması şöyle. 

This value causes the Kafka client to prefer IPv4 addresses over IPv6 addresses when resolving hostnames. This can be useful in cases where you have an IPv4-only Kafka cluster or network.

5. prefer_ipv6

Açıklaması şöyle. 

This value causes the Kafka client to prefer IPv6 addresses over IPv4 addresses when resolving hostnames. This can be useful in cases where you have an IPv6-only Kafka cluster or network.

metadata.max.age.ms ve metadata.refresh.interval.ms Alanları

Açıklaması şöyle. 

When a Kafka client needs to communicate with a broker, it uses the cached IP address for that broker to establish a network connection. If the cached IP address becomes invalid (e.g., because the broker has moved to a different machine), the client will perform DNS resolution again to obtain the updated IP address. The frequency at which the client updates its cached metadata and performs DNS resolution can be configured using the metadata.max.age.ms and metadata.refresh.interval.ms properties, respectively.