Preamble
Monitoring system is an indispensable part when deploying applications, in order to collect, track and analyze data related to the operational status and performance of resources, and at the same time bring issue timely warnings when the system crashes or is attacked. The monitoring system needs data, visual charts, and a warning system.
Introducing CloudWatch
CloundWatch is a monitoring service that tracks and collects not only aws of resources but also your application in real time. Besides, we can also monitor and collect log files, track performance, usage, health status. CloudWatch does not divide areas, so we can track the status of different instance instances on the same dashboard. With the basic feature, data is provided for a period of 5 minutes, but with the paid version, you can choose to track details by minute.
CloundWatch stores data for about 15 months, so even if terminating the instance, we can still access this resource.
CloundWatch Architechture
Here we take a look at some common features and benefits that they bring
- Monitor EC2 : Helps track the health and performance of all EC2 instances without installing any additional software. These metrics include:% CPU, Network, storage etc. It also allows us to set some customizations and track information about it on the center console.
- Monitor other resources : Besides, we can also monitor other services such as S3, RDS,
- Tracking and Storing Logs : Storing logs is extremely necessary, it allows us to collect information for analysis and troubleshooting.
- Set Alarms : We can set alerts for the data we need to monitor whenever they exceed a threshold, such as setting an alert when the RDS CPU usage exceeds 50% in a 10 minute period. , or set an alert in case the estimated payment charges exceed the amount we expect.
AWS CloudWatch create Alarms
AWS CloudWatch create Alarms- Dashboard : Allows creating dashboard with charts and statistics for all AWS resources, on this panel we can also set up various chart types such as lines, stacks, numbers: tracking charts redis server, sidekiq worker, app server CPU, app server network …
- Reaction when resources change : CloudWatch can detect and respond almost realtime when there is a resource change, we can integrate these events with lamda or SNS to automatically send feedback.
Components of CloudWatch
1. Metrics : This is the data that you collect periodically over a period of time, used to evaluate the status of resources in use. These data cannot be deleted manually and it will expire after 15 months. Units of measurement can be bytes, seconds or percent. The time interval for taking data may be 1s, 5s, or multiples of 60 (s). 
2. Events : AWS Events is also another useful component of CloudWatch, providing continuous status flow whenever resources change, it complements metrics, providing a comprehensive picture of the overall state. of the system. The life cycle of events is described in the image below 
Services like EC2, auto scaling, CloudTrail automatically send events to cloudwatch. We can also create custom events for our application using the Putivents api
3. Alarms : We can create alerts for any monitored resources such as EC2, S3, EBS, RDS, billing. Each alert will perform one or more actions depending on whether the data exceeds the threshold one or more times in a period. These actions can be EC2 actions, auto scalling, or notification for SNS topics. We can create alerts for different functions such as: start, stop, delete or restore EC2 version, but the maximum can only create 5000 alerts. 
Conclude
The AWS monitoring system provides us with a full range of services as well as features and solutions to meet all manual or automatic monitoring requirements, for simple to complex workloads. complex, centralized, or distributed, and it’s built-in to AWS services, which means you don’t have to pay extra for using monitoring systems for your aws services. use. AWS allows monitoring of all resources on their cloud platform including resources, services, and applications on it. In this article, we have covered the features and benefits of CloundWatch components such as: Metrics, Dashboards, Events, Alams