Important
This article covers the older managed image technology. For the most current technology, customers are encouraged to use Azure Compute Gallery. All new features, like ARM64, Trusted Launch, and Confidential VM are only supported through Azure Compute Gallery. If you have an existing managed image, you can use it as a source and create an Azure Compute Gallery image. For more information, see Create an image definition and image version.
Once you mark a VM as generalized
in Azure, you cannot restart the VM.
One managed image supports up to 20 simultaneous deployments. Attempting to create more than 20 VMs concurrently, from the same managed image, may result in provisioning timeouts due to the storage performance limitations of a single VHD. To create more than 20 VMs concurrently, use an Azure Compute Gallery (formerly known as Shared Image Gallery) image configured with 1 replica for every 20 concurrent VM deployments.
For information on how managed images are billed, see Managed Disks pricing.