The driver web ui's executors page can't load properly through kubectl proxy

[lins05]

Current when visit the spark driver web ui, the executors page can't load properly.

E.g. When I access the executors page at http://localhost:8001/api/v1/proxy/namespaces/default/services/spark-pi-1486223713270:4040/executors/, the js would try to use ajax to load the executors info from http://localhost:8001/api/v1/proxy/namespaces/api/v1/applications/namespaces/allexecutors.

This is because some special handling in the executors page's js for the "proxy" keywords in the url for yarn applications.

[ash211]

Good catch -- looks like that code indeed assumes that if proxy is in its URL then it's running in YARN, which has proxy URLs that look like

http://masternode:8088/proxy/application_1463264445515_0001/

However that doesn't work for k8s, which also has the word /proxy/ in its path... an unfortunate collision!

I think we can probably add another if block before the existing two using the search term api/v1/proxy/namespaces directly on the baseURI and return immediately if necessary (or do whatever changes).

@lins05 do you have bandwidth to take this one on? Probably the trickiest part will be ensuring that we don't break the YARN UI in the process.

[lins05]

SGTM, I'll submit a patch this week.