Implementing Memcached on EC2

Erik Osterman e at
Sun Jan 7 22:45:02 UTC 2007

David Phillips wrote:
> Have you looked at functions like AuthorizeSecurityGroupIngress?

I've been using the ability to authorize a subnet/ip, but I was unaware 
of the ability to create something like a vlan. Thanks for the tip. I 
checked it out and this should work very well! So, please disregard my 
request for authorization functionality in Memcached.

>> Discovery is a big issue in general with EC2.
> How about calling DescribeInstances?
Clearly, we're aware of this functionality; however, DescribeInstances 
simply lists the operating state of all instances 
(terminated/pending/running) it cannot convey any interal/application 
state. So, an instance might very well be running, but not be 
operational, which would require additional exploration/discovery. More 
over, DescribeInstances works in a polling fashion, which means to get 
frequently updated stats, we'd have to abuse their API, in addition to 
polling each instance for it's current run time status. Event based 
notification has been discussed on the ec2 forums, but is probably a 
ways away from getting released. Thus, having instances themselves 
notify our management server seems to be the most effective way of 
efficiently keeping a tally on what's truly available/operational and 
what's not.

Appreciated your feedback... sorry to everyone else for this drifting 
somewhat OT.


Erik Osterman

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