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Tanmay Shukla
Tanmay Shukla

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How can I connect or access an AWS S3 bucket from an Amazon EC2 Instance?

In this tutorial I'll show you step by step to connect & access your S3 bucket from EC2 instance via IAM Roles.

Step-1) Create an IAM instance profile that grants access to Amazon S3.

  • Open the IAM console.
  • Choose Roles, and then choose Create role.
  • Select AWS Service, and then choose EC2.
  • Select Next: Permissions.
  • Create a custom policy that provides the minimum required permissions to access your S3 bucket. Image 0

Note: Creating a policy with the minimum required permissions is a security best practice. However, to allow EC2 access to all your Amazon S3 buckets, you can use the AmazonS3ReadOnlyAccess or AmazonS3FullAccess managed IAM policy.

  • Select Next: Tags, and then select Next: Review.
  • Enter a Role name, and then select Create role.

Step-2) Create an EC2 instance and attach IAM instance profile to this instance

  • Create the EC2 instance (Launch an EC2 instance in 1 min)
  • For this click on checkbox on that instance and go to Actions tab > Security > Modify IAM role.
    Image 1

  • Now select the IAM role that you created in step-1 then save it. This will assign the IAM role to your ec2 instance.
    Image 2

Step-3) Validate S3 to check permissions, if it has any denying policy attached to it.

  • Go to Permissions>Bucket Policy then search fo Effect:Deny
  • Now in your bucket policy, edit or remove any Effect: Deny statements that are denying the IAM instance profile access to your bucket.

Image 3

Step-4) Check the network connectivity from EC2 instance to Amazon S3.

  • Verify if EC2 has network connectivity to S3 Endpoints
  • We need to make sure that our instance must possess one of the following quality
    • [] EC2 instance with a public IP address and a route table entry with the default route pointing to an Internet Gateway.
    • [] Private EC2 instance with a default route through a NAT gateway.
    • [] Private EC2 instance with connectivity to Amazon S3 using a Gateway VPC endpoint.

Step-5) Validate access to S3 buckets

  • First we need to Install AWS CLI Install or update AWS CLI
  • To Verify access to your S3 buckets by running the following command. Replace BUCKET-NAME with the name of your S3 bucket. This command will list all the objects in your bucket: ```

aws s3 ls s3://BUCKET-NAME

![Image 4](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/3tblxhd6h4dbu0fqm4il.png)
![Image 5](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/aom8g08cxzhlkivt34l3.png)

**Note:** Run the AWS s3 **cp** command to copy the files to the S3 bucket and vice versa but remember to give IAM role **AmazonS3FullAccess** or **AdminsterAccess**. 
Now as we have also installed the aws command line you can simply use the following commands to copy the files to S3 Bucket from EC2.
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To List the S3 Bucket

aws s3 ls s3://

To copy the files from EC2 to S3

aws s3 cp s3://

**<u>Addition resources:</u>**
- https://aws.amazon.com/premiumsupport/knowledge-center/ec2-instance-access-s3-bucket/
- https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html
- https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-troubleshooting.html

## Connect with me 
- [Github](https://github.com/tanmaycode2)
- [Linkedin](https://www.linkedin.com/in/tanmay-shukla/)
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