I'm seeing this message repeating over and over in the traffic controller
logs:
{"timestamp":1441830145.719944000,"process_id":32413,"source":"loggregator
trafficcontroller","log_level":"debug","message":"ServerAddressList.Run:
Unable to recursively find keys with prefix
/healthstatus/doppler","data":null,"file":"/opt/cloudfoundry/cf-release/src/loggregator/src/
github.com/cloudfoundry/loggregatorlib/servicediscovery/servicediscovery.go
","line":78,"method":"
github.com/cloudfoundry/loggregatorlib/servicediscovery.(*serverAddressList).DiscoverAddresses
"}

Here's my config:

"EtcdUrls" : ["http://localhost:4001"],
"EtcdMaxConcurrentRequests" : 10,
"WSMessageBufferSize": 100,
"OutgoingDropsondePort": 8082,
"DopplerPort": 8082,
"IncomingPort": 3456,
"OutgoingPort": 9090,
"SkipCertVerify": true,
"Index": 0,
"MaxRetainedLogMessages": 100,
"SharedSecret": "secret",
"Host": "0.0.0.0",
"SystemDomain": "local.example.com",
"ApiHost": "http://127.0.0.1:8181",

"NatsHosts": ["127.0.0.1"],
"NatsPort": 4222,
"NatsUser": "nats",
"NatsPass": "password",
"VarzUser": "varz",
"VarzPass": "password",
"VarzPort": 8888,
"MetronPort": 3457,
"Syslog" : "",
"Zone": "CRAZY_TOWN",

"UaaHost": "http://localhost:8080",
"UaaClientId": "doppler",
"UaaClientSecret": "tokensecret"
}

I have all the components running locally, using cf-release 215. I have two
questions:
1. what's causing this error?
2. if all I want out of the system are logs (via cf logs command), can I
get away with just having a traffic controller and dea agent running or do
I need metron and doppler?