<p>Creates or updates a metric stream. Metric streams can automatically stream CloudWatch metrics to Amazon Web Services destinations, including Amazon S3, and to many third-party solutions.</p> <p>For more information, see <a href="https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch-Metric-Streams.html"> Using Metric Streams</a>.</p> <p>To create a metric stream, you must be signed in to an account that has the <code>iam:PassRole</code> permission and either the <code>CloudWatchFullAccess</code> policy or the <code>cloudwatch:PutMetricStream</code> permission.</p> <p>When you create or update a metric stream, you choose one of the following:</p> <ul> <li> <p>Stream metrics from all metric namespaces in the account.</p> </li> <li> <p>Stream metrics from all metric namespaces in the account, except for the namespaces that you list in <code>ExcludeFilters</code>.</p> </li> <li> <p>Stream metrics from only the metric namespaces that you list in <code>IncludeFilters</code>.</p> </li> </ul> <p>By default, a metric stream always sends the <code>MAX</code>, <code>MIN</code>, <code>SUM</code>, and <code>SAMPLECOUNT</code> statistics for each metric that is streamed. You can use the <code>StatisticsConfigurations</code> parameter to have the metric stream send additional statistics in the stream. Streaming additional statistics incurs additional costs. For more information, see <a href="https://aws.amazon.com/cloudwatch/pricing/">Amazon CloudWatch Pricing</a>. </p> <p>When you use <code>PutMetricStream</code> to create a new metric stream, the stream is created in the <code>running</code> state. If you use it to update an existing stream, the state of the stream is not changed.</p> <p>If you are using CloudWatch cross-account observability and you create a metric stream in a monitoring account, you can choose whether to include metrics from source accounts in the stream. For more information, see <a href="https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch-Unified-Cross-Account.html">CloudWatch cross-account observability</a>.</p>

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