I have been reading about various architecture stacks of larger websites and came across imgur's. They seem to have all of their subdomains (api.imgur.com, cdn.imgur.com, imgur.com...) all pointing to one HAProxy instance that then divides up traffic to appropriate ELBs and associated instances.
Here is a diagram of their system:
Why not just have the DNS resolve each sub domain to the appropriate ELB ip directly? What's the benefit of HAProxy? Or is it just a remnant of a legacy system.
I have been reading up on Redis with AWS Elasticache and am a little confused on security. So far, it seems the only security is to create a Redis Security Group that only allows access from either a specific security group or IP address.
Is there any additional security I can/should add?
Is there any way to attatch Redis access security to IAM Roles?
I am creating my own VPC and was reading some documentation. AWS documentation for DNS with VPC (click here to view) says
To enable an EC2 instance to be publicly accessible, it must have a public IP address, a DNS hostname, and DNS resolution.
Is this true? Why?
Is a private IP address in combination with an elastic IP address not enough to access the instance publicly and privately?
I am averaging 12,000 page views per day, but my cloudfront is getting around 6 million requests for images and fonts every day. I suppose it is possible that all of these requests are coming from my visitors, but I am having my doubts.
I know that I can enable keys and cookies so that only users of my website will be able to access the cloudfront servers, but I am not convinced yet that this is necessary.
Is there a way for me to check what percentage of the requests are from users that are being referenced from my server? Before I go and change my code to work with the private origin access?