Azure provides sandbox environments that allow users to test and experiment with Azure resources without affecting production or other environments. However, the specific details about cluster customization and connection types are not mentioned in the provided context.
If you are looking for a sandbox to create infrastructure with specific configurations like cluster customization, you might want to explore Azure Arc, which allows you to manage Kubernetes clusters from various environments, including on-premises and other cloud providers.
For messaging, if you need to send messages that require a minimum character count, ensure that your message meets the necessary criteria for the platform you are using.
For more specific guidance on Azure Blueprints or other Azure services, please refer to the Azure documentation or resources related to your needs.