Amazon CloudWatch

官方：

详细文档：http://aws.amazon.com/documentation/

Amazon CloudWatch is a web service that provides monitoring for AWScloud resources, starting with Amazon EC2. It provides customers with visibility into resource utilization, operational performance, and overall demand patterns—including metrics such as CPU utilization, disk reads and writes, and network traffic. To use Amazon CloudWatch, simply select the Amazon EC2 instances that you’d like to monitor; within minutes, Amazon CloudWatch will begin aggregating and storing monitoring data that can be accessed using web service APIs or Command Line Tools.

To access Amazon CloudWatch:

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Features of Amazon CloudWatch

• Amazon CloudWatch enables you to monitor your Amazon EC2 instances and  in real-time.
• Amazon CloudWatch enables , which allows you to dynamically add or remove Amazon EC2instances based on Amazon CloudWatch metrics. Auto Scaling is free to Amazon CloudWatch customers.
• You pay as you go and only incur Amazon CloudWatch fees for Amazon EC2 instances you choose to monitor.
• If you’re signed up for the Amazon EC2 service, you’re already registered to use Amazon CloudWatch and can begin using the feature via the Amazon CloudWatch APIs or Command Line Tools.
• You do not need to install additional software to monitor Amazon EC2 or Elastic Load Balancers.
• Amazon CloudWatch is available in the US Region and will be available in the EU Region soon.

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Using Amazon CloudWatch

Getting started with using Amazon CloudWatch is easy. If you are signed up for the Amazon EC2 service, you are automatically registered for Amazon CloudWatch. You simply:

• Download the Command Line Tools from Amazon EC2 API tools.
• Use the ec2-monitor-instances command to enable monitoring for any running Amazon EC2 instance. If you want to launch Amazon EC2 instances with monitoring enabled, you can do so by passing a monitoringparameter to the ec2-run-instances command.
• Use the mon-get-stats to view metrics for an Amazon EC2 instance or Elastic Load Balancer.

All the commands mentioned above are also available as Amazon CloudWatch APIs.

Amazon CloudWatch provides customers with visibility into resource utilization, operational issues, and overall demand patterns. Amazon CloudWatch can aggregate and report metrics for CPU utilization, data transfer, and the disk usage and activity for each Amazon EC2 instance. It also monitors Elastic Load Balancers for metrics such as request count and request latency. Amazon CloudWatch can aggregate data by Availability Zone, Auto Scaling Group, AMI type or Elastic Load Balancer. Monitoring data is persisted for 2 weeks, even if the Amazon EC2instances or Elastic Load Balancers have been terminated. This enables you to quickly look back at the metrics preceding an event of interest to you.

Amazon CloudWatch enables Auto Scaling, which allows you to dynamically add or remove Amazon EC2 instances based on Amazon CloudWatch metrics. You can define conditions upon which you want to scale up or down your Amazon EC2 instances. When Auto Scaling detects that the conditions have been met, it automatically adds or removes the specified amount of Amazon EC2 instances. This ability to dynamically add and remove Amazon EC2instances enables you to follow your application demand curve much more closely than ever before.

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Projecting Costs

With Amazon CloudWatch, you only pay for what you use. Amazon CloudWatch is charged by the number of Amazon EC2 instances you monitor, at a rate of $0.015 per hour for each Amazon EC2 instance you choose to monitor. You will be charged at the end of each month for your Amazon EC2 instances monitored by Amazon CloudWatch.

As an example, a developer may want to monitor 10 Amazon EC2 instances 24×7 for a 30-day period. The Amazon CloudWatch cost would be $108 (or $0.015 per Amazon EC2 instance hour x 10 Amazon EC2 instances x 24 hours per day x 30 days). Partial hours will be billed as full hours. Regular  apply and are billed separately.