A few hours ago, Amazon launched a monitoring service for EC2 instances which they are calling CloudWatch. The service costs 1.5 cents per hour per EC2 instance (of any size) which comes out to $10.95 per month for an instance running 24x7.
The concurrently announced Load Balancing and Auto Scaling services are powerful, but I’m not so sure that CloudWatch is going to be useful by itself.
My initial impression on using CloudWatch is that it is hard enough to set up and use that most folks are going to get lost figuring out how to get regular, useful information out of it. Some of this could be alleviated by improved documentation, but I still think the direct, raw usage has a small target audience.
Most users on EC2 should be able to get by with free monitoring packages like munin. Since munin is running on the instance itself, it has access to many more metrics than CloudWatch. Plus it provides pretty graphs which are much easier on the eye than the raw CloudWatch output.
Munin is also trivial to set up on Ubuntu. It takes one command:
sudo apt-get install munin munin-node apache2
Wait 10 minutes for it to start collecting data, then point your browser at http://HOSTNAME/munin
There is a bit more work to do if you want to collect all of your munin data for multiple servers in a central location or to create summary charts combining metrics, but you can get a lot of value from just the above.
Reasons you might end up using CloudWatch include:
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You are using Amazon’s new EC2 Auto Scaling feature which requires CloudWatch. In this case, you shouldn’t have to worry about the gory details since Auto Scaling will take care of the monitoring for you.
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You need access to accurate network and disk IO numeric values measured in the same way that Amazon uses to charge you. E.g., you might be running sets of instances for clients and want to pass on EC2 charges to them.
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You are using a lot of EC2 instances in a large organization and have the time and expertise to implement data collection with CloudWatch for presenting in your own internal reports.
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You are creating some tools to help other people use the CloudWatch service more easily and with pretty graphs.
On that last point, I think there is an interesting opportunity for somebody to write munin plugins for CloudWatch. It looks like the monitoring data is available on a near-real time basis, and with a bit of state-keeping it should be possible to get graphs which closely represent Amazon’s monitoring records.
I’ve posted some of my feedback from testing CloudWatch on the EC2 forum.
If you’ve had a chance to check out CloudWatch, what is your opinion?