Hi developers,
I’m proposing KIP-601 to support configurable socket connection timeout. https://cwiki.apache.org/confluence/display/KAFKA/KIP-601%3A+Configurable+socket+connection+timeout <https://cwiki.apache.org/confluence/display/KAFKA/KIP-601:+Configurable+socket+connection+timeout> Currently, the initial socket connection timeout is depending on system setting tcp_syn_retries. The actual timeout value is 2 ^ (tcp_sync_retries + 1) - 1 seconds. For the reasons below, we want to control the client-side socket timeout directly using configuration files. • The default value of tcp_syn_retries is 6. It means the default timeout value is 127 seconds and too long in some scenarios. For example, when the user specifies a list of N bootstrap-servers and no connection has been built between the client and the servers, the least loaded node provider will poll all the server nodes specified by the user. If M servers in the bootstrap-servers list are offline, the client may take (127 * M) seconds to connect to the cluster. In the worst case when M = N - 1, the wait time can be several minutes. • Though we may set the default value of tcp_syn_retries smaller, we will then change the system level network behaviors, which might cause other issues. • Applications depending on KafkaAdminClient may want to robustly know and control the initial socket connect timeout, which can help throw corresponding exceptions in their layer. Please let me know if you have any thoughts or suggestions. Thanks. Best, - Cheng Tan
