Monasca Fluentd output plugin generates key not found: :ciphers error

[Doug Szumski]

The following traceback may be seen (from a Centos deploy, but may also affect Ubuntu):

```
2021-01-06 09:42:01 +0000 [info]: #0 starting fluentd worker pid=8760 ppid=7 worker=0
2021-01-06 09:42:01 +0000 [error]: #0 unexpected error error_class=KeyError error="key not found: :ciphers"
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/rest-client-1.8.0/lib/restclient/request.rb:163:in `fetch'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/rest-client-1.8.0/lib/restclient/request.rb:163:in `initialize'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/rest-client-1.8.0/lib/restclient/request.rb:41:in `new'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/rest-client-1.8.0/lib/restclient/request.rb:41:in `execute'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/rest-client-1.8.0/lib/restclient/resource.rb:67:in `post'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-monasca-output-1.0.1/lib/fluent/plugin/keystone/keystone_client.rb:38:i
n `request'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-monasca-output-1.0.1/lib/fluent/plugin/keystone/keystone_client.rb:31:i
n `authenticate'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-monasca-output-1.0.1/lib/fluent/plugin/out_monasca.rb:82:in `authentica
te'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-monasca-output-1.0.1/lib/fluent/plugin/out_monasca.rb:42:in `start'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/compat/call_super_mixin.rb:42:in `start'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/root_agent.rb:200:in `block in start'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/root_agent.rb:189:in `block (2 levels) in lifecycle'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/root_agent.rb:188:in `each'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/root_agent.rb:188:in `block in lifecycle'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/root_agent.rb:175:in `each'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/root_agent.rb:175:in `lifecycle'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/root_agent.rb:199:in `start'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/engine.rb:248:in `start'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/engine.rb:147:in `run'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/supervisor.rb:603:in `block in run_worker'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/supervisor.rb:840:in `main_process'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/supervisor.rb:594:in `run_worker'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/lib/fluent/command/fluentd.rb:361:in `<top (required)>'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:72:in `require'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/2.7.0/rubygems/core_ext/kernel_require.rb:72:in `require'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-1.11.2/bin/fluentd:8:in `<top (required)>'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/bin/fluentd:23:in `load'
  2021-01-06 09:42:01 +0000 [error]: #0 /opt/td-agent/bin/fluentd:23:in `<top (required)>'
  2021-01-06 09:42:01 +0000 [error]: #0 /usr/sbin/td-agent:7:in `load'
  2021-01-06 09:42:01 +0000 [error]: #0 /usr/sbin/td-agent:7:in `<main>'
2021-01-06 09:42:01 +0000 [error]: #0 unexpected error error_class=KeyError error="key not found: :ciphers"
  2021-01-06 09:42:01 +0000 [error]: #0 suppressed same stacktrace
2021-01-06 09:42:01 +0000 [info]: Worker 0 finished unexpectedly with status 1
```

This appears to be related to a Ruby upgrade, rather than td-agent which remains pinned to the same major release.

In Ussuri we have (works):

```
(fluentd)[root@control01 /]# cat /etc/centos-release
CentOS Linux release 8.3.2011
(fluentd)[root@control01 /]# td-agent --version
td-agent 1.11.5
(fluentd)[root@control01 /]# find / -name monasca_api_client.rb
/opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-monasca-output-1.0.1/lib/fluent/plugin/monasca/monasca_api_client.rb
```

From Victoria (broken):

```
(fluentd)[root@control01 /]# cat /etc/centos-release
CentOS Linux release 8.3.2011
(fluentd)[root@control01 /]# td-agent --version
td-agent 1.11.2
(fluentd)[root@control01 /]# find / -name monasca_api_client.rb
/opt/td-agent/lib/ruby/gems/2.7.0/gems/fluentd-monasca-output-1.0.1/lib/fluent/plugin/monasca/monasca_api_client.rb
```

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/kolla 12.0.0.0rc1 release candidate.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/kolla 11.1.0 release.