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+# Amazon Web Services
+
+1. [Constraints](#constraints)
+1. [Further readings](#further-readings)
+   1. [Sources](#sources)
+
+## Constraints
+
+| data type | component | summary                        | description                                                                                                                                                                                                                                                | type   | length   | pattern                           | required |
+| --------- | --------- | ------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------ | -------- | --------------------------------- | -------- |
+| tag       | key       | Required name of the tag       | The string value can be Unicode characters and cannot be prefixed with "aws:".<br/>The string can contain only the set of Unicode letters, digits, white-space, `_`,' `.`, `/`, `=`, `+`, `-`, `:`, `@` (Java regex: `^([\\p{L}\\p{Z}\\p{N}_.:/=+\\-]*)$`) | String | 1 to 128 | `^([\p{L}\p{Z}\p{N}_.:/=+\-@]*)$` | Yes      |
+| tag       | value     | The optional value of the tag. | The string value can be Unicode characters. The string can contain only the set of Unicode letters, digits, white-space, `_`, `.`, `/`, `=`, `+`, `-`, `:`, `@` (Java regex: `^([\\p{L}\\p{Z}\\p{N}_.:/=+\\-]*)$"`)                                        | String | 0 to 256 | `^([\p{L}\p{Z}\p{N}_.:/=+\-@]*)$` | Yes      |
+
+## Further readings
+
+### Sources
+
+- [Constraints for tags][constraints  tag]
+
+<!--
+  References
+  -->
+
+<!-- In-article sections -->
+<!-- Knowledge base -->
+<!-- Files -->
+<!-- Upstream -->
+[constraints  tag]: https://docs.aws.amazon.com/directoryservice/latest/devguide/API_Tag.html
+
+<!-- Others -->
diff --git a/knowledge base/cloud computing/aws/ecr.md b/knowledge base/cloud computing/aws/ecr.md
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+# Elastic Container Registry
+
+1. [TL;DR](#tldr)
+1. [Further readings](#further-readings)
+   1. [Sources](#sources)
+
+## TL;DR
+
+## Further readings
+
+- AWS' [CLI]
+
+### Sources
+
+- [Using pull through cache rules]
+- [Creating a lifecycle policy preview]
+
+<!--
+  References
+  -->
+
+<!-- In-article sections -->
+<!-- Knowledge base -->
+[cli]: cli.md
+
+<!-- Files -->
+<!-- Upstream -->
+[creating a lifecycle policy preview]: https://docs.aws.amazon.com/AmazonECR/latest/userguide/lpp_creation.html
+[using pull through cache rules]: https://docs.aws.amazon.com/AmazonECR/latest/userguide/pull-through-cache.html
+
+<!-- Others -->
diff --git a/knowledge base/cloud computing/aws/s3.md b/knowledge base/cloud computing/aws/s3.md
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+# Simple Storage Service
+
+1. [Lifecycle configuration](#lifecycle-configuration)
+1. [Further readings](#further-readings)
+   1. [Sources](#sources)
+
+## Lifecycle configuration
+
+When you have multiple rules in an S3 Lifecycle configuration, an object can become eligible for multiple S3 Lifecycle actions. In such cases, Amazon S3 follows these general rules:
+
+1. Permanent deletion takes precedence over transition.
+1. Transition takes precedence over creation of delete markers.
+1. When an object is eligible for both a S3 Glacier Flexible Retrieval and S3 Standard-IA (or S3 One Zone-IA) transition, Amazon S3 chooses the S3 Glacier Flexible Retrieval transition.
+
+Propagation delay: When you add an S3 Lifecycle configuration to a bucket, there is usually some lag before a new or updated Lifecycle configuration is fully propagated to all the Amazon S3 systems. Expect a delay of a few minutes before the configuration fully takes effect. This delay can also occur when you delete an S3 Lifecycle configuration.
+
+Objects can only go down the tiers, not up. Many other constraints apply, like no transition done for objects <128KiB.<br/>
+See [General considerations for transitions][lifecycle  general considerations for transitions].
+
+## Further readings
+
+- [Configure notification for lifecycle rules][lifecycle  configure notification]
+
+### Sources
+
+- [General considerations for transitions][lifecycle  general considerations for transitions]
+- [Lifecycle configuration examples][lifecycle  configuration examples]
+
+<!--
+  References
+  -->
+
+<!-- In-article sections -->
+<!-- Knowledge base -->
+<!-- Files -->
+<!-- Upstream -->
+[lifecycle  configuration examples]: https://docs.aws.amazon.com/AmazonS3/latest/userguide/lifecycle-configuration-examples.html
+[lifecycle  configure notification]: https://docs.aws.amazon.com/AmazonS3/latest/userguide/lifecycle-configure-notification.html
+[lifecycle  general considerations for transitions]: https://docs.aws.amazon.com/AmazonS3/latest/userguide/lifecycle-transition-general-considerations.html
+
+<!-- Others -->