My current website architecture has two Ubuntu servers with public IPs in Rackspace Cloud. One of them is web and mysql server. The other one is for time-consuming calculations only. Both of them have Iptables which allow all outbound traffic and inbound HTTP, HTTPS, SSH and established connections. I connect to the servers with ssh using password, but this connection is protected with Fail2ban. I use unattended upgrades to keep the servers updated.
I'm moving to Amazon AWS and considering to change my current architecture to use a VPC with Public and Private Subnets. However, I have some doubts:
- I would use a default (small) nat instance. I assume that it needs to keep updated, does it update automatically?
- I would have three other instances: a web server in the public subnet and a mysql server and a computation server in the private subnet. How do I access each of these instances with ssh?
- Is this architecture more secure than my current one?