Arvados

PUT "foo" at the same time (~1s) yields:

acbd18db4cc2f85cedef654fccc4a4d8+3+A4c4f3a5266482fc749c72d2265c533990ebe2aae@53cde0cf ← keepserver
acbd18db4cc2f85cedef654fccc4a4d8+3+A9abcab7c98791fbf0c78ee385a8f3b0c2ec5975a@53cde0cf ← keepproxy

Quick scan of source code suggests PUT requests are done with the keep proxy's ARVADOS_API_TOKEN env var.

With my own token, arv-put fails:

arv-put foo.txt
0M / 0M 100.0% 
Traceback (most recent call last):
  File "/usr/local/bin/arv-put", line 4, in <module>
    main()
  File "/usr/local/lib/python2.7/dist-packages/arvados/commands/put.py", line 394, in main
    'manifest_text': writer.manifest_text(),
  File "/usr/local/lib/python2.7/dist-packages/oauth2client/util.py", line 132, in positional_wrapper
    return wrapped(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/apiclient/http.py", line 723, in execute
    raise HttpError(resp, content, uri=self.uri)
apiclient.errors.HttpError: <HttpError 403 when requesting https://qr1hi.arvadosapi.com/arvados/v1/collections?alt=json returned "Forbidden">

If I copy ARVADOS_API_TOKEN from keepproxy's environment into my own environment, arv-put succeeds:

$ arv-put foo.txt
0M / 0M 100.0%
83367e8913dcec0bf3fc25ed5a27eacb+49

...which seems to support this theory.