amazon web services - AWS S3 upload without access and secret key in Java

Question

I want to upload a file to S3 without using my access and secret key from AWS server. AWS keys should be taken as default. However running the below command in server I can access it without providing any access and secret keys.

aws s3 cp somefile.txt s3://somebucket/

From java code its not accessible since it was unable to load credentials. Below is my code.

AmazonS3 s3client = new AmazonS3Client(new DefaultAWSCredentialsProviderChain());

Answer 1

You can use the below Java code to get the s3client instance when you are trying to connect to S3 bucket from EC2 instance.

AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
              .withCredentials(new InstanceProfileCredentialsProvider(false))
              .build();

This is the recommended way as the application doesn't require to maintain the access keys in property files.

• IAM role should be created and S3 access should be provided for that role. See the sample policy below.
• The IAM role should be assigned to the EC2 instance

Sample policy for IAM role:-

{
        "Action": ["s3:PutObject",
        "s3:ListBucket",
        "s3:GetObject",
        "s3:DeleteObject"],
        "Resource": ["arn:aws:s3:::yourBucketName",
        "arn:aws:s3:::yourBucketName/*"],
        "Effect": "Allow",
        "Sid": "AllowBucketLinux"
    }