input log file :
Sep 9 07:50:43 es-rclarke dhclient: bound to 10.10.10.89 -- renewal in 426936 seconds.
config file is as follows:
filter {
grok {
match => {
"message" => "%{SYSLOGLINE}"
}
overwrite => [ "message" ]
}
grok {
match => {
"message" => "bound to %{IPV4:[dhclient][address]} -- renewal in %{INT:[dhclient][renewal]:int} seconds."
}
tag_on_failure => []
}
}
In the above two grok patterns especially-SYSLOGLINE stands for?
likewise why the field names are in two square brackets like [dhcclient][address] and [dhclient][renewal]