Add fs.s3n.awsAccessKeyId and fs.s3n.awsSecretAccessKey to mesos-site.xml and include them in core-site.xml

[rolandomanrique]

Add configuration parameters for AWS key and secret to be used in core-site.xml. Resulting XML in core-site.xml should look like this:

    <property>
     <name>fs.s3n.awsAccessKeyId</name>
     <value>{AWS_ACCESS_KEY}</value>
    </property>

    <property>
     <name>fs.s3n.awsSecretAccessKey</name>
     <value>{AWS_SECRET_KEY}</value>
    </property>

[abhay-agarwal]

Any *-site.xml files in the conf directory will automatically be built into the tarball so users can write this on their own.

[elingg]

@abhay-agarwal, Actually they are referring to distributing core-site.xml with configserver so it picks up the environment variables which we don't yet do.

[elingg]

Note there is a security conern with using these parameters so we may not want these defined by default. Per @brndnmtthws "One other note: you may not want to define the fs.s3.aws* parameters. HDFS's s3:// protocol is for S3-backed block-based storage, which is usually not what people want. If you omit the params, people won't be able to use s3:// by accident, and thereby messing up whatever's in that bucket. There's more on this here: https://wiki.apache.org/hadoop/AmazonS3". @rmvz, let us know whether you think it's worth having these parameters by default due to this security concern.

[elingg]

Talked to @rmvz, and he is not using the parameter for block based storage in order to avoid touching other resources by using "fs.s3n.aws" instead of “fs.s3.aws.”