udp

The
in_udp
Input plugin enables Fluentd to accept UDP payload.It is included in Fluentd's core.
<source>
@type udp
tag mytag # required
<parse>
@type regexp
expression /^(?<field1>\d+):(?<field2>\w+)$/
</parse>
port 20001 # optional. 5160 by default
bind 0.0.0.0 # optional. 0.0.0.0 by default
message_length_limit 1MB # optional. 4096 bytes by default
</source>
Refer to the Configuration File article for the basic structure and syntax of the configuration file.
We have observed drastic performance improvements on Linux, with proper kernel parameter settings (e.g.
net.core.rmem_max
parameter). If you have high-volume UDP traffic, please make sure to follow Before Installing Fluentd instructions.The value must be
udp
.type | default | version |
---|---|---|
string | required parameter | 0.14.0 |
The tag of the output events.
type | default | version |
---|---|---|
integer | 5160 | 0.14.0 |
The port to listen to. (default:
5160
)type | default | version |
---|---|---|
string | 0.0.0.0 (all addresses) | 0.14.0 |
The bind address to listen to.
type | default | version |
---|---|---|
string | nil (no adding hostname) | 0.14.10 |
The field name of the client's hostname. If it is set, the client's hostname will be set to its key.
If you set the following configuration:
source_hostname_key client_host
then the client's hostname is set to
client_host
field i.e.:{
...
"foo": "bar",
"client_host": "client.hostname.org"
}
type | default | version |
---|---|---|
string | nil (no adding source address) | 1.4.2 |
The field name for the client's IP address. If you set this option, Fluentd automatically adds the remote address to each data record.
For example, if you have the following configuration:
<source>
@type udp
source_address_key client_addr
# ...
</source>
You will get something like this:
{
...
"client_addr": "192.168.10.10"
...
}
type | default | version |
---|---|---|
size | 4096 | 0.14.14 |
The maximum number of bytes for the message.
type | default | version |
---|---|---|
bool | true | 0.14.23 |
Removes the newline from the end of the incoming payload.
required | multi | version |
---|---|---|
true | false | 0.14.10 |
in_udp
uses the parser plugin to parse the payload.For more details:
Here is a Ruby example to send an event to
in_udp
:require 'socket'
us = UDPSocket.open
sa = Socket.pack_sockaddr_in(5160, '127.0.0.1')
# This example uses json payload.
# In in_udp configuration, need to configure "@type json" in "<parse>"
us.send('{"k":"v1"}', 0, sa)
us.send('{"k":"v2"}', 0, sa)
us.close
If
in_udp
gets lots of packets within 1 sec, some packets are dropped. For example, you can see bigger RcvbufErrors
number via netstat -su
.If you are trying to receive binary data containing '\r' (
0x0d
) or '\n' (0x0a
), you need to tweak remove_newline
to prevent Fluentd from corrupting payloads.For example, suppose you intend to receive packets which contain the following data:
\xa9test\ntest (0xa9, 0x74, 0x65, 0x73, 0x74, 0xa, 0x74, 0x65, 0x73, 0x74)
you need to be careful that the default behaviour of Fluentd is to trim the 6th byte (
0x0a
) from payload. If you do not want this behaviour, please configure remove_newline
to false
.If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is an open-source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.
Last modified 11mo ago