It's just a matter of alternatives. There's frankly no other IaaS out there that can match the features of EC2 (eg, EBS, elastic IP). These guys are unstoppable, they come out with more features every week.
a) Ability to map an elastic IP to an ELB. The CNAME thing it uses now has way too many drawbacks [1].
b) Ability to make an RDS instance a slave to or a master for a normal MySQL instance. This would make it possible to use RDS as a backup to our ordinary DB infrastructure using normal MySQL replication (and eventually, vice versa)
c) Retention periods for EBS snapshots. You can get this yourself by writing a few simple scripts, but it would be really nice if snapshots could simply be labelled "delete after 90 days".
d) A cross-availability zone, synchronously replicated EBS volume. This is probably fairly specific to our use case, but it would be neat if AWS natively provided something like DRBD.
[1] http://blog.pagerduty.com/2010/08/31/load-balancers-need-sta...
Let us add dev pay instances to an ELB.
More ram.
Elastic private ip addresses.
Change security groups of running instances.
I have a lot more, but those are my big ones.
I say "feel" advisedly. I don't have inner knowledge. It's just that the explanation up to this point doesn't seem all that compelling; for what seems like rather dubious benefits it seems like they've taken on an awful lot of risks they have little ability to manage themselves.
http://techblog.netflix.com/2010/12/four-reasons-we-choose-a...
The problems [Amazon] are trying to solve are incredibly difficult ones, but they aren’t specific to our business. Every successful internet company has to figure out great storage solutions, hardware failover, networking infrastructure, etc.
Their third argument for virtualized infrastructure was "We're not very good at predicting customer growth or device engagement", which strikes me as a compelling problem to solve. Having to change their approach to managing service dependencies and failures doesn't seem like too high a price to pay.
This is not Netflix's core competency either. This is the core competency of a CDN. If you have problems like this, you should almost certainly hire one, and architect accordingly.
Netflix has long since done so:
http://blog.streamingmedia.com/the_business_of_online_vi/201...
netflix actually uses many cdns, including akamai and l3.
Now with AWS, they can spin up additional instances at will.