Load balancer
HAProxy is a good load balancer.
AWS "Elastic Load Balancer" (ELB) - now called 'Classic Load Balancer' is not so capable. But it does cost a lot, so there's that feature ;-)
NGINX is also a good load balancer. Check this comparison I know 'feature lists' made by the vendor tend to put a lot of gloss on their own products, but this is a fair comparison.