Confusion on AWS Cloudwatch and Application Logs

Question

I have an on-premise app deployed in an Application Server (e.g. Tomcat) and it generates its own log file. If I decide to migrate this to an AWS EC2, including the Application Server, is it possible to port my application logs in Cloudwatch instead? or is Cloudwatch only capable of logging the runtime logs in my application server? is it a lot of work to do this or is this even possible?

Kind of confuse on Cloudwatch. Seems it can do multiple things but is it really right to make it do that? Its only supposed to log metrics right, so it can alert whatever or whoever needs to be alerted.

Answer 1

If you have already developed application that produces its own log files, you can use CloudWatch Logs Agent to ingest the logs into CloudWatch Logs:

After installation is complete, logs automatically flow from the instance to the log stream you create while installing the agent. The agent confirms that it has started and it stays running until you disable it.

The metrics, such as RAM usage, disk space, can also be monitored and pushed to CloudWatch through the agent.

In both cases, logs and metrics, you can setup CloudWatch Alarms to automatically detect anomalies and notify you, or perform other actions, when they are detected. For logs, this is done through metric filters:

You can search and filter the log data coming into CloudWatch Logs by creating one or more metric filters. Metric filters define the terms and patterns to look for in log data as it is sent to CloudWatch Logs. CloudWatch Logs uses these metric filters to turn log data into numerical CloudWatch metrics that you can graph or set an alarm on.

update

You can also have your application to inject logs directly to CloudWatch logs using AWS SDK. For example, in python, you can use put_log_events.