Updated on 2022-08-12 GMT+08:00

Network communication (via Netty)

Scenario

When Flink runs a job, data transmission and reverse pressure detection between tasks depend on Netty. In certain environments, Netty parameters should be configured.

Configuration Description

For advanced optimization, you can modify the following Netty configuration items. The default configuration can meet the requirements of tasks of large-scale clusters with high concurrent throughput. For details about the parameters, visit the Netty official website at http://netty.io/.

Table 1 Parameter description

Parameter

Description

Default Value

Mandatory

taskmanager.network.netty.num-arenas

Number of Netty memory blocks.

1

No

taskmanager.network.netty.server.numThreads

Number of Netty server threads

1

No

taskmanager.network.netty.client.numThreads

Number of Netty client threads

1

No

taskmanager.network.netty.client.connectTimeoutSec

Netty client connection timeout duration. Unit: second

120

No

taskmanager.network.netty.sendReceiveBufferSize

Size of Netty sending and receiving buffers. This defaults to the system buffer size (cat /proc/sys/net/ipv4/tcp_[rw]mem) and is 4 MB in modern Linux. Unit: byte

4096

No

taskmanager.network.netty.transport

Netty transport type, either nio or epoll

nio

No