HADOOP-18382. AWS SDK v2 upgrade prerequisites (#4698)
This patch prepares the hadoop-aws module for a future
migration to using the v2 AWS SDK (HADOOP-18073)
That upgrade will be incompatible; this patch prepares
for it:
-marks some credential providers and other
classes and methods as @deprecated.
-updates site documentation
-reduces the visibility of the s3 client;
other than for testing, it is kept private to
the S3AFileSystem class.
-logs some warnings when deprecated APIs are used.
The warning messages are printed only once
per JVM's life. To disable them, set the
log level of org.apache.hadoop.fs.s3a.SDKV2Upgrade
to ERROR
Contributed by Ahmar Suhail
38 files changed
