.NET container images offer several image variants.
.NET images for Ubuntu, Debian, Azure Linux, Windows Server Core, and Nano Server images are full-featured and include ICU libraries which provide Unicode and globalization support.
As of .NET 8, we also guarantee these images include time zone information (e.g. tzdata in Linux).
These images are intended to satisfy the most common use cases of .NET developers.
Alpine and Ubuntu Chiseled .NET images are focused on size.
By default, these images do not include icu or tzdata, meaning that these images only work with apps that are configured for globalization-invariant mode.
Apps that require globalization support can use the extra image variant of the dotnet/runtime-deps images. Because this is only available with runtime-deps images, it requires a self-contained deployment of the application.
Alpine, Azure Linux, and Ubuntu Chiseled images also come in extra, composite, and aot variants (see below).
Ubuntu Chiseled and Azure Linux distroless .NET images contain only the minimum set of libraries necessary to run .NET applications with everything else removed. For more information, see the Distroless .NET images documentation.
For apps that depend on globalization functionality, the extra image variant is offered for Ubuntu Chiseled and Azure Linux distroless runtime-deps, runtime, and aspnet images as well as runtime-deps images for Alpine Linux.
These extra images contain everything that the default images do, plus icu and tzdata.
ASP.NET Core Composite images provide a smaller size on disk while keeping the performance of the default ReadyToRun (R2R) setting. The caveat is that the composite images have tighter version coupling. This means the final app run on them cannot use handpicked custom versions of the framework and/or ASP.NET assemblies that are built into the composite binary. For a full technical description on how the composites work, we have a feature doc here.
The aot images provide an optimized deployment size for Native AOT compiled .NET apps.
Native AOT has the lowest size, startup time, and memory footprint of all .NET deployment models.
Please see "Limitations of Native AOT deployment" to see if your app might be compatible.
aot image variants are only available for our size-focused runtime-deps images: Alpine and Ubuntu Chiseled.
They also require the use of the aot SDK image which include extra libraries needed for Native AOT compilation.
Note
aot images are only available as a preview in the dotnet/nightly/sdk and dotnet/nightly/runtime-deps repos.
Native AOT compiled apps will function exactly the same on the existing runtime-deps (non-aot) images, but with a larger deployment size.
Please try out these new, smaller images and give us feedback!