Add support for IPv6

docker/Dockerfile

@@ -46,7 +46,8 @@ RUN yum update -y \
 RUN groupadd -r $FLUENT_USER && \
   useradd -r -g $FLUENT_USER $FLUENT_USER && \
   mkdir -p /fluentd/log /fluentd/etc /fluentd/plugins && \
-  chown -R $FLUENT_USER /fluentd && chgrp -R $FLUENT_USER /fluentd
+  chown -R $FLUENT_USER /fluentd && chgrp -R $FLUENT_USER /fluentd && \
+  chmod +t /tmp
 
 USER $FLUENT_USER
 CMD bundle exec fluentd -c /fluentd/etc/fluent.conf

lib/fluent/plugin/in_kubernetes_metrics.rb

@@ -17,6 +17,7 @@
 require 'fluent/plugin/input'
 require 'kubeclient'
 require 'multi_json'
+require 'resolv'
 
 module Fluent
   module Plugin
@@ -76,6 +77,8 @@ class KubernetesMetricsInput < Fluent::Plugin::Input
       def configure(conf)
         super
 
+        @kubelet_address = "[#{@kubelet_address}]" if @kubelet_address =~ Resolv::IPv6::Regex
+
         if @use_rest_client
           raise Fluentd::ConfigError, 'node_name is required' if @node_name.nil? || @node_name.empty?
         else
@@ -136,6 +139,7 @@ def init_without_kubeconfig(_options = {})
         if @kubernetes_url.nil?
           # Use Kubernetes default service account if we're in a pod.
           env_host = ENV['KUBERNETES_SERVICE_HOST']
+          env_host = "[#{env_host}]" if env_host =~ Resolv::IPv6::Regex
           env_port = ENV['KUBERNETES_SERVICE_PORT']
           if env_host && env_port
             @kubernetes_url = "https://#{env_host}:#{env_port}/api/"

test/plugin/test_in_kubernetes_metrics.rb

@@ -109,6 +109,30 @@ def create_driver(conf = CONFIG)
     assert_equal true, d.instance.use_rest_client
   end
 
+  test 'IPv6 node configuration' do
+    IPv6_CONFIG = %(
+      type kubernetes_metrics
+      node_name generics-aws-node-name
+      tag kube.*
+      insecure_ssl true
+      interval 10s
+      use_rest_client true
+      use_rest_client_ssl false
+      kubelet_port 10_255
+      kubelet_address fd55:4d62:e00f::1
+    )
+    assert_nothing_raised(Fluent::ConfigError) do
+      create_driver(IPv6_CONFIG)
+    end
+
+    d = create_driver(IPv6_CONFIG)
+    assert_equal '[fd55:4d62:e00f::1]', d.instance.kubelet_address
+    assert_equal 'http://[fd55:4d62:e00f::1]:10255/stats/summary', d.instance.instance_variable_get('@kubelet_url')
+    assert_equal 'http://[fd55:4d62:e00f::1]:10255/stats', d.instance.instance_variable_get('@kubelet_url_stats')
+    assert_equal 'http://[fd55:4d62:e00f::1]:10255/metrics/cadvisor', d.instance.instance_variable_get('@cadvisor_url')
+
+  end
+
   sub_test_case 'node_unit_tests' do
     test 'test_emit_cpu_metrics' do
       assert_not_nil @@hash_map_test.key?('kube.node.cpu.usage')