Update S3/EC2 Documentation

[dadoonet]

Now we have moved to secure settings for S3 and removed/deprecated some settings like region, we must update the documentation.

I'm just adding this issue so we don't forget to do it.

Some users are yet hitting this:

• https://discuss.elastic.co/t/s3-repository-deprecated-settings-warning/92354
• https://discuss.elastic.co/t/elasticsearch-yml-chanages-2-x-to-5-x-on-aws-ec2-amazon-linux/88041/6
• https://discuss.elastic.co/t/getting-aws-credentials-from-keystore-for-discovery-ec2-plugin/87958/5

I'm summarizing here major changes so if anyone in the meantime is hitting this, we can refer them to this issue:

Using secure settings

You now need to register the following secured settings (see https://www.elastic.co/guide/en/elasticsearch/reference/5.5/secure-settings.html):

For EC2

• discovery.ec2.access_key
• discovery.ec2.secret_key

For S3

• s3.client.default.access_key
• s3.client.default.secret_key

region is replaced by endpoint

And cloud.aws.region should not be used anymore.

For EC2

discovery.ec2.endpoint needs to be set in elasticsearch.yml file. Pick your endpoint from this list: http://docs.aws.amazon.com/general/latest/gr/rande.html#ec2_region

For S3

s3.client.default.endpoint needs to be set in elasticsearch.yml file. Pick your endpoint from this list: http://docs.aws.amazon.com/general/latest/gr/rande.html#s3_region