# Process flow log records in CloudWatch Logs


You can process flow log records as you would with any other log events collected by CloudWatch Logs. For more information about monitoring log data and metric filters, see [Creating metrics from log events using filter](https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/MonitoringLogData.html) in the *Amazon CloudWatch Logs User Guide*.

## Example: Create a CloudWatch metric filter and alarm for a flow log


In this example, you have a flow log for `eni-1a2b3c4d`. You want to create an alarm that alerts you if there have been 10 or more rejected attempts to connect to your instance over TCP port 22 (SSH) within a 1-hour time period. First, you must create a metric filter that matches the pattern of the traffic for which to create the alarm. Then, you can create an alarm for the metric filter.

**To create a metric filter for rejected SSH traffic and create an alarm for the filter**

1. Open the CloudWatch console at [https://console.aws.amazon.com/cloudwatch/](https://console.aws.amazon.com/cloudwatch/).

1. In the navigation pane, choose **Logs**, **Log groups**.

1. Select the check box for the log group, and then choose **Actions**, **Create metric filter**.

1. For **Filter pattern**, enter the following string.

   ```
   [version, account, eni, source, destination, srcport, destport="22", protocol="6", packets, bytes, windowstart, windowend, action="REJECT", flowlogstatus]
   ```

1. For **Select log data to test**, select the log stream for your network interface. (Optional) To view the lines of log data that match the filter pattern, choose **Test pattern**.

1. When you're ready, choose **Next**.

1. Enter a filter name, metric namespace, and metric name. Set the metric value to 1. When you're done, choose **Next** and then choose **Create metric filter**.

1. In the navigation pane, choose **Alarms**, **All alarms**.

1. Choose **Create alarm**.

1. Select the metric name that you created and then choose **Select metric**.

1. Configure the alarm as follows, and then choose **Next**:
   + For **Statistic**, choose **Sum**. This ensure that you capture the total number of data points for the specified time period.
   + For **Period**, choose **1 hour**.
   + For **Whenever TimeSinceLastActive is...**, choose **Greater/Equal** and enter 10 for the threshold.
   + For **Additional configuration**, **Datapoints to alarm**, leave the default of 1.

1. Choose **Next**.

1. For **Notification**, select an existing SNS topic or choose **Create new topic** to create a new one. Choose **Next**.

1. Enter a name and description for the alarm and choose **Next**.

1. When you are done previewing the alarm, choose **Create alarm**.