configuration consistency with other jaeger components

[naseemkullah]

Hello @pavolloffay @yurishkuro @jpkrohling

Requirement - what kind of business use case are you trying to solve?

Trying to reuse config across various jaeger components. Works quite well except for schema, spark-job and es-index-cleaner components. This issue is to address the inconsistencies with spark. A separate issue was opened to address es index cleaner but "closed as wont-fix": jaegertracing/jaeger#2124.

Problem - what in Jaeger blocks you from solving the requirement?

example:
spark-job -> ES_NODES, CASSANDRA_CONTACT_POINTS
other components -> ES_SERVER_URLS, CASSANDRA_SERVERS

Proposal - what do you suggest to solve the problem or improve the existing situation?

Keep environment variable names consistent with main components (collector, query, ingester)

[jpkrohling]

I'm all for naming consistency, especially if they follow the same syntax (comma-separated URL values, host:port, ...) and have the same semantics. I think @pavolloffay mentioned that some values might not be consistent, so, I think the first step would be to map all the vars and their values. We can then map and decide whether we want to rename the properties. In the end, it should also be clear whether we might end up with name clashes as well.