Amazon EC2 instance can't update or use yum

Looks like the host is having trouble contacting the yum server. Make sure the instance has outbound internet access (check security groups etc). If the instance is in a VPC and the security groups look good you may need to use a nat appliance or attach an elastic IP.

Good luck-

If you have an S3 endpoint on your VPC then this will cause yum to fail as repo file is stored in S3. To fix this add the following policy to S3:

{
"Version": "2012-10-17",
"Statement": [
    {
        "Effect": "Allow",
        "Principal": "*",
        "Action": "*",
        "Resource": [
            "arn:aws:s3:::repo.eu-west-1.amazonaws.com",
            "arn:aws:s3:::repo.eu-west-1.amazonaws.com/*"
        ]
    }
]
}

Replace eu-west-1 with the relevant region code that your S3 endpoint is in.

A lot of first time users of Amazon EC2 run into this issue. In my experience, it's usually the result of not setting the allowed outgoing connections on their instance's security group. The tutorial that Amazon has for configuring Amazon Linux instances only mentions setting the Incoming connections so it's easy to forget that you never set the allowed outgoing ones. Simply allowing HTTP and HTTPS requests to any IP Address should fix the issue.