feat(fluentd): support containerd log format

Signed-off-by: Cryptophobia <aouzounov@gmail.com>

README.md

@@ -13,6 +13,12 @@ This work is based on the [docker-fluentd](https://github.com/fabric8io/docker-f
 
 ## Configuration
 
+### Support containerd log format
+By default, fluent parses logs in docker json format. If you use containerd, you only need to set the following environment variables
+
+* `CONTAINER_TAIL_PARSER_TYPE="/^(?<time>.+) (?<stream>stdout|stderr)( (?<tags>.))? (?<log>.*)$/"`
+
+
 ### Enable more verbose logging
 By default we do not capture kubernetes system logs. However, it is possible to tell fluentd to capture those logs just by specifying a few new environment variables.
 

rootfs/fluentd/sbin/sources

@@ -1,16 +1,19 @@
 #!/bin/bash
 if [ -e "/var/log/containers" ]
 then
+
 cat << EOF >> $FLUENTD_CONF
 <source>
   @type tail
   path /var/log/containers/*.log
   pos_file /var/log/containers.log.pos
-  time_key time
-  time_format %Y-%m-%dT%H:%M:%S.%L%z
   tag kubernetes.*
-  format json
   read_from_head true
+  <parse>
+    @type "#{ENV['CONTAINER_TAIL_PARSER_TYPE'] || 'json'}"
+    time_key time
+    time_format %Y-%m-%dT%H:%M:%S.%L%z
+  </parse>
 </source>
 EOF