Merge pull request #273731 from allyford/fips-os-options

fips-os-options

Author: prmerger-automator[bot]

articles/aks/enable-fips-nodes.md

@@ -33,6 +33,23 @@ The Federal Information Processing Standard (FIPS) 140-2 is a US government stan
 >
 > FIPS-enabled node images may have different version numbers, such as kernel version, than images that aren't FIPS-enabled. The update cycle for FIPS-enabled node pools and node images may differ from node pools and images that aren't FIPS-enabled.
 
+## Supported OS Versions
+You can create FIPS-enabled node pools on all supported OS types, Linux and Windows. However, not all OS versions support FIPS-enabled nodepools. After a new OS version is released, there is typically a waiting period before it is FIPS compliant.
+
+The below table includes the supported OS versions:
+
+|OS Type|OS SKU|FIPS Compliance|
+|--|--|--|
+|Linux|Ubuntu|Supported|
+|Linux|Azure Linux| Supported|
+|Windows|Windows Server 2019| Supported|
+|Windows| Windows Server 2022| Supported|
+
+When requesting FIPS enabled Ubuntu, if the default Ubuntu version does not support FIPS, AKS will default to the most recent FIPS-supported version of Ubuntu. For example, Ubuntu 22.04 is default for Linux node pools. Since 22.04 does not currently support FIPS, AKS will default to Ubuntu 20.04 for Linux FIPS-enabled nodepools.
+
+> [!NOTE]
+ > Previously, you could use the GetOSOptions API to determine whether a given OS supported FIPS. The GetOSOptions API is now deprecated and it will no longer be included in new AKS API versions starting with 2024-05-01. 
+
 ## Create a FIPS-enabled Linux node pool
 
 1. Create a FIPS-enabled Linux node pool using the [`az aks nodepool add`][az-aks-nodepool-add] command with the `--enable-fips-image` parameter.