If you are getting any values from the MDC resolver, then you have the MDC
resolver configured correctly.
You're only going to get MDC values like collection/shard/replica if those
are defined for the thread that logged the message you are looking at.
In the specific example you posted...
: {"core":"corepo","rid":"null-5","trace_id":"null-5"}
...thta "core" name does not look like a a core name that solr would have
created in solr cloud mode -- it looks like maybe you are just running a
trivial example solr instance where you manually created a core? ... in
which case there is no collection/shard/replica data to include in the MDC
for that request.
-Hoss
http://www.lucidworks.com/
