CloudWatch

Amazon CloudWatch provides a reliable, scalable, and flexible monitoring solution that you can start using within minutes. You no longer need to set up, manage, and scale your own monitoring systems and infrastructure.

• Use CloudWatch to monitor your AWS resources and the applications you run on AWS in real time.
• Use CloudWatch Events to send system events from AWS resources to AWS Lambda functions, Amazon SNS topics, streams in Amazon Kinesis, and other target types with the help of Simple Notificaton Service (SNA).
• Use CloudWatch Logs to monitor, store, and access your log files from Amazon EC2 instances, AWS CloudTrail, or other sources.

“Cloud Watch is service to set alarms based on Service metric threshold”

“Cloud Watch is service to trigger actions based on Service metric threshold”

“Cloud Watch is service to targetting actions based on Events or State change of resources”

In the event of Production crash at mid night, everyone in your team will be panic mode.  Amazon CloudWatch service is very useful and reliable to manage this kind of issues in producton environment.

Below are the best example of using CloudWatch Services in Amazon Cloud Environment.

• DynamoDB Read/Write Throughput
• EC2 CPU Usage
• Estimated Billing Charges

CloudWatch service for “Alarm / Notificatoins”

By setting alarms and notificaton on services like DynamoDB, EC2 and Billing services, CloudWatch will monitor these service metric threshold, if threshold reaches then CloudWatch service will send alarm or notificaions as SMS, Email, HTTP via SNS service.

CloudWatch service for “Actions”

CloudWatch is service which is not only being used to send alarm or notificatons.  It may trigger some actions like Autoscaling, EC2, and etc.,  In case of "action needs to be triggered” out of any CloudWatch events then Action related group of services will be used instead of Simple notification services.

CloudWatch service Dashboard Walkthrough

Amazon CloudWatch services monitors operational and performance metrics for your AWS cloud resources and applications. Below is the CloudWatch Dashboard and its specific services which will help set Alarms and Action on the event of service metric threshold. Below is Amazon CloudWatch Dashboard and its services with brief explanation.

Alarms:

You can create a CloudWatch alarm that watches a single metric. The alarm performs one or more actions and notifications based on the value of the metric relative to a threshold over a number of time periods. The action can be an Amazon EC2 action, an Auto Scaling action, or a notification sent to an Amazon SNS topic.

An alarm has three possible states:

• OK—The metric is within the defined threshold
• ALARM—The metric is outside of the defined threshold
• INSUFFICIENT_DATA—The alarm has just started, the metric is not available, or not enough data is available for the metric to determine the alarm state

Events:

CloudWatch Events helps you to respond to state changes in your AWS resources. When your resources change state they automatically send events into an event stream. You can create rules that match selected events in the stream and route them to targets to take action. You can also use rules to take action on a pre-determined schedule. For example, you can configure rules to:

• Automatically invoke an AWS Lambda function to update DNS entries when an event notifies you that Amazon EC2 instance enters the Running state
• Direct specific API records from CloudTrail to a Kinesis stream for detailed analysis of potential security or availability risks
• Take a snapshot of an Amazon EBS volume on a schedule

Amazon CloudWatch Events delivers a near real-time stream of system events that describe changes in Amazon Web Services (AWS) resources. Using simple rules that you can quickly set up, you can match events and route them to one or more target functions or streams. CloudWatch Events becomes aware of operational changes as they occur. CloudWatch Events responds to these operational changes and takes corrective action as necessary, by sending messages to respond to the environment, activating functions, making changes, and capturing state information.

You can also use CloudWatch Events to schedule automated actions that self-trigger at certain times using cron or rate expressions.

Event Buses:

Default event bus accepts events from AWS services, PutEvents API calls, and other authorized accounts. You can manage permissions on the default event bus to authorize other accounts. Other AWS accounts can share their events with you by adding your default event bus as a target to their rules.

Logs:

You can use Amazon CloudWatch Logs to monitor, store, and access your log files from Amazon Elastic Compute Cloud (Amazon EC2) instances, AWS CloudTrail, Amazon Route 53, and other sources. You can then retrieve the associated log data from CloudWatch Logs.

• Monitor HTTP response codes in Apache logs
• Receive alarms for errors in kernel logs
• Count exceptions in application logs

Metrics:

Metrics are data about the performance of your systems. By default, several services provide free metrics for resources (such as Amazon EC2 instances, Amazon EBS volumes, and Amazon RDS DB instances). You can also enable detailed monitoring some resources, such as your Amazon EC2 instances, or publish your own application metrics. Amazon CloudWatch can load all the metrics in your account (both AWS resource metrics and application metrics that you provide) for search, graphing, and alarms.

Metric data is kept for a period of 15 months, enabling you to view both up-to-the-minute data and historical data.