You can use Amazon CloudWatch Logs to monitor, store, and access your log files from\nEC2 instances, CloudTrail, and other sources. You can then retrieve the associated\nlog data from CloudWatch Logs using the CloudWatch console. Alternatively, you can use\nCloudWatch Logs commands in the Amazon Web Services CLI, CloudWatch Logs API, or CloudWatch\nLogs SDK.
\nFor more information about CloudWatch Logs features, see the\nAmazon CloudWatch Logs User Guide.
\nYou can use CloudWatch Logs to:
\n\nMonitor logs from EC2 instances in real time: You\ncan use CloudWatch Logs to monitor applications and systems using log data. For example,\nCloudWatch Logs can track the number of errors that occur in your application logs. Then,\nit can send you a notification whenever the rate of errors exceeds a threshold that you\nspecify. CloudWatch Logs uses your log data for monitoring so no code changes are\nrequired. For example, you can monitor application logs for specific literal terms (such\nas \"NullReferenceException\"). You can also count the number of occurrences of a literal\nterm at a particular position in log data (such as \"404\" status codes in an Apache access\nlog). When the term you are searching for is found, CloudWatch Logs reports the data to a\nCloudWatch metric that you specify.
\n\nMonitor CloudTrail logged events: You\ncan create alarms in CloudWatch and receive notifications of particular API activity as\ncaptured by CloudTrail. You can use the notification to perform troubleshooting.
\n\nArchive log data: You can use CloudWatch Logs to\nstore your log data in highly durable storage. You can change the log retention setting so\nthat any log events earlier than this setting are automatically deleted. The CloudWatch\nLogs agent helps to quickly send both rotated and non-rotated log data off of a host and\ninto the log service. You can then access the raw log data when you need it.
\nCloudWatch Logs might log request contents for fields that aren't considered\nsensitive, such as API request parameters for CloudWatch Logs actions. This provides\ndebugging information for failed API requests.
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