Amazon CloudWatch | AWS Resource and Custom Metrics Monitoring Flashcards
Why does my AWS monthly bill for CloudWatch appear different between July 2017 and previous months?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
Prior to July 2017, charges for CloudWatch were split under two different sections in your AWS bill and Cost and Usage Reports. For historical reasons, charges for CloudWatch Alarms, CloudWatch Metrics, and CloudWatch API usage were reported under the “Elastic Compute Cloud” (EC2) detail section of your bill, while charges for CloudWatch Logs and CloudWatch Dashboards are reported under the “CloudWatch” detail section. To help consolidate and simplify your monthly AWS CloudWatch usage and billing, we moved the charges for your CloudWatch Metrics, Alarms, and API usage from the “EC2” section of your bill to the “CloudWatch” section, effectively bringing together all of your CloudWatch monitoring charges under the “CloudWatch” section. Note that this has no impact to your total AWS bill amount. Your bill and Cost and Usage Reports will now simply display charges for CloudWatch under a single section.
Additionally, there is a Billing Metric in CloudWatch named “Estimated Charges” that can be viewed as Total Estimated Charge or broken down By Service. The “Total Estimated Charge” metric will not change. However, the “EstimatedCharges” metric broken down by Service will change for dimension ServiceName equal to “AmazonEC2” and dimension ServiceName equal to “AmazonCloudWatch”. Due to the billing consolidation, you may see that your AmazonEC2 billing metric decrease and AmazonCloudWatch billing metric increase as usage and billing charges get moved out of EC2 and into CloudWatch.
What can I measure with Amazon CloudWatch Metrics?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
Amazon CloudWatch allows you to monitor AWS cloud resources and the applications you run on AWS. Metrics are provided automatically for a number of AWS products and services, including Amazon EC2 instances, EBS volumes, Elastic Load Balancers, Auto Scaling groups, EMR job flows, RDS DB instances, DynamoDB tables, ElastiCache clusters, RedShift clusters, OpsWorks stacks, Route 53 health checks, SNS topics, SQS queues, SWF workflows, and Storage Gateways. You can also monitor custom metrics generated by your own applications and services.
What is the retention period of all metrics?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
CloudWatch launched High Resolution Custom Metrics on July 26, 2017. This enables you to publish and store custom metrics down to 1-second resolution. Extended retention of metrics was launched on November 1, 2016, and enabled storage of all metrics for customers from the previous 14 days to 15 months. CloudWatch retains metric data as follows:
Data points with a period of less than 60 seconds are available for 3 hours. These data points are high-resolution custom metrics.
Data points with a period of 60 seconds (1 minute) are available for 15 days
Data points with a period of 300 seconds (5 minute) are available for 63 days
Data points with a period of 3600 seconds (1 hour) are available for 455 days (15 months)
Data points that are initially published with a shorter period are aggregated together for long-term storage. For example, if you collect data using a period of 1 minute, the data remains available for 15 days with 1-minute resolution. After 15 days this data is still available, but is aggregated and is retrievable only with a resolution of 5 minutes. After 63 days, the data is further aggregated and is available with a resolution of 1 hour. If you need availability of metrics longer than these periods, you can use the GetMetricStatistics API to retrieve the datapoints for offline or different storage.
The feature is currently available in US East (N. Virginia), US West (Oregon), US West (N. California), EU (Ireland), EU (Frankfurt), S. America (São Paulo), Asia Pacific (Singapore), Asia Pacific (Tokyo), Asia Pacific (Seoul), Asia Pacific (Mumbai), Asia Pacific (Sydney), EU (London), Canada (Central), US East (Ohio), and China (Beijing).
What is the minimum resolution for the data that Amazon CloudWatch receives and aggregates?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
The minimum resolution supported by CloudWatch is 1-second data points, which is a high-resolution metric, or you can store metrics at 1-minute granularity. Sometimes metrics are received by Cloudwatch at varying intervals, such as 3-minute or 5-minute intervals. If you do not specify that a metric is high resolution, by setting the StorageResolution field in the PutMetricData API request, then by default CloudWatch will aggregate and store the metrics at 1-minute resolution.
Depending on the age of data requested, metrics will be available at the resolutions defined in the retention schedules above. For example, if you request for 1-minute data for a day from 10 days ago, you will receive the 1440 data points. However, if you request for 1-minute data from 5 months back, the UI will automatically change the granularity to 1-hour and the GetMetricStatistics API will not return any output.
Can I delete any metrics?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
CloudWatch does not support metric deletion. Metrics expire based on the retention schedules described above.
Will I lose the metrics data if I disable monitoring for an Amazon EC2 instance?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
No. You can always retrieve metrics data for any Amazon EC2 instance based on the retention schedules described above. However, the CloudWatch console limits the search of metrics to 2 weeks after a metric is last ingested to ensure that the most up to date instances are shown in your namespace.
Can I access the metrics data for a terminated Amazon EC2 instance or a deleted Elastic Load Balancer?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
Yes. Amazon CloudWatch stores metrics for terminated Amazon EC2 instances or deleted Elastic Load Balancers for 15 months.
Why does the graphing of the same time window look different when I view the metrics in 5 minute and 1 minute periods?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
If you view the same time window in a 5 minute period versus a 1 minute period, you may see that data points are displayed in different places on the graph. For the period you specify in your graph, Amazon CloudWatch will find all the available data points and calculates a single, aggregate point to represent the entire period. In the case of a 5 minute period, the single data point is placed at the beginning of the 5 minute time window. In the case of a 1 minute period, the single data point is placed at the 1 minute mark. We recommend using a 1 minute period for troubleshooting and other activities that require the most precise graphing of time periods.
What is a Custom Metric?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
You can use Amazon CloudWatch to monitor data produced by your own applications, scripts, and services. A custom metric is any metric you provide to Amazon CloudWatch. For example, you can use custom metrics as a way to monitor the time to load a web page, request error rates, number of processes or threads on your instance, or amount of work performed by your application. You can get started with custom metrics by using the PutMetricData API, our sample monitoring scripts for Windows and Linux, CloudWatch collectd plugin, as well as a number of applications and tools offered by AWS partners.
What resolution can I get from a Custom Metric?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
A custom metric can be one of the following:
Standard resolution, with data having one-minute granularity
High resolution, with data at a granularity of one second
By default, metrics are stored at 1-minute resolution in CloudWatch. You can define a metric as high-resolution by setting the StorageResolution parameter to 1 in the PutMetricData API request. If you do not set the optional StorageResolution parameter, then CloudWatch will default to storing the metrics at 1-minute resolution.
When you publish a high-resolution metric, CloudWatch stores it with a resolution of 1 second, and you can read and retrieve it with a period of 1 second, 5 seconds, 10 seconds, 30 seconds, or any multiple of 60 seconds.
Custom metrics follow the same retention schedule listed above.
What metrics are available at high resolution?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
Currently, only custom metrics that you publish to CloudWatch are available at high resolution. High-resolution custom metrics are stored in CloudWatch at 1-second resolution. High resolution is defined by the StorageResolution parameter in the PutMetricData API request, with a value of 1, and is not a required field. If you do not specify a value for the optional StorageResolution field, then CloudWatch will store the custom metric at 1-minute resolution by default.
Are high-resolution custom metrics priced differently than regular custom metrics?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
No, high-resolution custom metrics are priced in the same manner as standard 1-minute custom metrics.
When would I use a Custom Metric over having my program emit a log to CloudWatch Logs?
AWS Resource and Custom Metrics Monitoring
Amazon CloudWatch | Management Tools
You can monitor your own data using custom metrics, CloudWatch Logs, or both. You may want to use custom metrics if your data is not already produced in log format, for example operating system processes or performance measurements. Or, you may want to write your own application or script, or one provided by an AWS partner. If you want to store and save individual measurements along with additional detail, you may want to use CloudWatch Logs.
