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Currently, enabling CMK during the creation of an Azure Cosmos DB for PostgreSQL Cluster might not be supported directly in Terraform. Therefore, you will not find a reference for it in the Terraform or Azure documentation.
CMK is availble for cosmos db account which doesnot support postgres sql.
CMK is available for cosmos db for postgre sql. Please refer to this documentation: Enable data encryption with customer-managed keys in Azure Cosmos DB for PostgreSQL
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