Parse nginx ingress logs in fluentd

Question

I'd like to parse ingress nginx logs using fluentd in Kubernetes. That was quite easy in Logstash, but I'm confused regarding fluentd syntax.

Right now I have the following rules:

<source>
  type tail
  path /var/log/containers/*.log
  pos_file /var/log/es-containers.log.pos
  time_format %Y-%m-%dT%H:%M:%S.%NZ
  tag kubernetes.*
  format json
  read_from_head true
  keep_time_key true
</source>

<filter kubernetes.**>
  type kubernetes_metadata
</filter>

And as a result I get this log but it is unparsed:

127.0.0.1 - [127.0.0.1] - user [27/Sep/2016:18:35:23 +0000] "POST /elasticsearch/_msearch?timeout=0&ignore_unavailable=true&preference=1475000747571 HTTP/2.0" 200 37593 "http://localhost/app/kibana" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Centos Chromium/52.0.2743.116 Chrome/52.0.2743.116 Safari/537.36" 951 0.408 10.64.92.20:5601 37377 0.407 200

I'd like to apply filter rules to be able to search by IP address, HTTP method, etc in Kibana. How can I implement that?

Answer 1

Pipelines are quite different in logstash and fluentd. And it took some time to build working Kubernetes -> Fluentd -> Elasticsearch -> Kibana solution.

Short answer to my question is to install fluent-plugin-parser plugin (I wonder why it doesn't ship within standard package) and put this rule after kubernetes_metadata filter:

<filter kubernetes.var.log.containers.nginx-ingress-controller-**.log>
  type parser
  format /^(?<host>[^ ]*) (?<domain>[^ ]*) \[(?<x_forwarded_for>[^\]]*)\] (?<server_port>[^ ]*) (?<user>[^ ]*) \[(?<time>[^\]]*)\] "(?<method>\S+[^\"])(?: +(?<path>[^\"]*?)(?: +\S*)?)?" (?<code>[^ ]*) (?<size>[^ ]*)(?: "(?<referer>[^\"]*)" "(?<agent>[^\"]*)")? (?<request_length>[^ ]*) (?<request_time>[^ ]*) (?:\[(?<proxy_upstream_name>[^\]]*)\] )?(?<upstream_addr>[^ ]*) (?<upstream_response_length>[^ ]*) (?<upstream_response_time>[^ ]*) (?<upstream_status>[^ ]*)$/
  time_format %d/%b/%Y:%H:%M:%S %z
  key_name log
  types server_port:integer,code:integer,size:integer,request_length:integer,request_time:float,upstream_response_length:integer,upstream_response_time:float,upstream_status:integer
  reserve_data yes
</filter>

Long answer with lots of examples is here: https://github.com/kayrus/elk-kubernetes/