Fluentd unexpected error error both URI are relative

Issue

Fluentd pods are not sending logs to Elasticsearch and they keep restarting with the following error trace

  2017-07-04 17:32:34 +0200 [error]: unexpected error error="both URI are relative"
  2017-07-04 17:32:34 +0200 [error]: /usr/share/ruby/uri/generic.rb:1203:in `rescue in merge'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/ruby/uri/generic.rb:1200:in `merge'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/kubeclient-1.1.4/lib/kubeclient/common.rb:140:in `create_rest_client'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/kubeclient-1.1.4/lib/kubeclient/common.rb:328:in `block in api'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/kubeclient-1.1.4/lib/kubeclient/common.rb:58:in `handle_exception'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/kubeclient-1.1.4/lib/kubeclient/common.rb:327:in `api'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/kubeclient-1.1.4/lib/kubeclient/common.rb:322:in `api_valid?'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluent-plugin-kubernetes_metadata_filter-0.26.2/lib/fluent/plugin/filter_kubernetes_metadata.rb:167:in `configure'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/agent.rb:145:in `add_filter'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/agent.rb:62:in `block in configure'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/agent.rb:57:in `each'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/agent.rb:57:in `configure'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/root_agent.rb:83:in `block in configure'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/root_agent.rb:83:in `each'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/root_agent.rb:83:in `configure'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/engine.rb:129:in `configure'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/engine.rb:103:in `run_configure'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/supervisor.rb:489:in `run_configure'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/supervisor.rb:160:in `block in start'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/supervisor.rb:366:in `call'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/supervisor.rb:366:in `main_process'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/supervisor.rb:339:in `block in supervise'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/supervisor.rb:338:in `fork'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/supervisor.rb:338:in `supervise'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/supervisor.rb:156:in `start'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/lib/fluent/command/fluentd.rb:173:in `<top (required)>'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in `require'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in `require'
  2017-07-04 17:32:34 +0200 [error]: /usr/share/gems/gems/fluentd-0.12.31/bin/fluentd:5:in `<top (required)>'
  2017-07-04 17:32:34 +0200 [error]: /usr/bin/fluentd:23:in `load'
  2017-07-04 17:32:34 +0200 [error]: /usr/bin/fluentd:23:in `<main>'
  2017-07-04 17:32:34 +0200 [error]: fluentd main process died unexpectedly. restarting.