apache-kafka - -IV0 版本后缀是什么意思？

Question

我们在三节点 Azure 集群中部署了 Apache Kafka 0.10.2.0。我们没有指定 log.message.format.version server.properties 中的选项文件，所以我们希望它应该是 Kafka 版本(即 0.10.2.0 )。

但是在尝试执行 Kafka 代理滚动升级时，我们注意到 log.message.format.version=0.10.2.0-IV0在服务器日志中。

根据Kafka upgrade guide 看来那log.message.format.version总是 与Kafka版本本身完全相同 (当然，如果没有被 server.properties 配置覆盖)。

-IV0 是什么意思版本号后缀是什么意思？

为什么log.message.format.version默认与Kafka版本不同？

Answer 1

基本上，IV0 , IV1 , IV2 etc. 是 Kafka 版本中的协议(protocol)版本。一个特定的 Kafka 版本在开发过程中可以有多个协议(protocol)更改。

Since the api protocol may change more than once within the same release and to facilitate people deploying code from trunk, we have the concept of internal versions (first introduced during the 0.10.0 development cycle). For example, the first time we introduce a version change in a release, say 0.10.0, we will add a config value "0.10.0-IV0" and a corresponding case object KAFKA_0_10_0-IV0. We will also add a config value "0.10.0" that will be mapped to the latest internal version object, which is KAFKA_0_10_0-IV0. When we change the protocol a second time while developing 0.10.0, we will add a new config value "0.10.0-IV1" and a corresponding case object KAFKA_0_10_0-IV1. We will change the config value "0.10.0" to map to the latest internal version object KAFKA_0_10_0-IV1. The config value of "0.10.0-IV0" is still mapped to KAFKA_0_10_0-IV0. This way, if people are deploying from trunk, they can use "0.10.0-IV0" and "0.10.0-IV1" to upgrade one internal version at a time. For most people who just want to use released version, they can use "0.10.0" when upgrading to the 0.10.0 release.

(来自Kafka源代码: https://github.com/apache/kafka/blob/c216adb4bbf8306977380a1ec371380e30137765/core/src/main/scala/kafka/api/ApiVersion.scala#L30)