Merge pull request #310230 from mbender-ms/lb-freshness-0126

Load Balancer | Content Maintenance | Freshness for January

Author: denrea

articles/load-balancer/admin-state-overview.md

@@ -6,51 +6,51 @@ services: load-balancer
 author: mbender-ms
 ms.service: azure-load-balancer
 ms.topic: concept-article
-ms.date: 10/17/2024
+ms.date: 01/07/2026
 ms.author: mbender
 ms.custom: references_regions
 # Customer intent: As a cloud administrator, I want to configure the administrative state of backend instances in a load balancer, so that I can control traffic availability during maintenance, patching, or testing without impacting existing connections.
 ---
 
 # Administrative State (Admin State) in Azure Load Balancer
 
-Administrative state (Admin state) is a feature of Azure Load Balancer that allows you to override the Load Balancer’s health probe behavior on a per backend pool instance basis. This feature is useful in scenarios where you would like to take down your backend instance for maintenance, patching, or testing.
+Administrative state (Admin state) is a feature of Azure Load Balancer that allows you to override the Load Balancer's health probe behavior on a per backend pool instance basis. This feature is useful in scenarios where you would like to take down your backend instance for maintenance, patching, or testing.
 
 ## Why use admin state? 
 
 Admin state is useful in scenarios where you want to have more control over the behavior of your Load Balancer. For example, you can set the admin state to up to always consider the backend instance eligible for new connections, even if the health probe indicates otherwise. Conversely, you can set the admin state to down to prevent new connections, even if the health probe indicates that the backend instance is healthy. This can be useful for maintenance or other scenarios where you want to temporarily take a backend instance out of rotation.
 
-:::image type="content" source="media/admin-state-overview/admin-state-overview.png" alt-text="Diagram of admin state usage and state values.":::
+:::image type="content" source="media/admin-state-overview/admin-state-overview.png" alt-text="Screenshot of admin state usage and state values diagram showing the relationship between admin state settings and load balancer behavior.":::
 
 ## Types of admin state values 
 
 There are three types of admin state values: **Up**, **Down**, **None**. The following table describes the effects of each state on new connections and existing connections:
 
 | **Admin State** | **New Connections** | **Existing Connections** |
 |-------------|-----------------|----------------------|
-| **Up**         | Load balancer ignores the health probe and always considers the backend instance as eligible for new connections. | Load balancer disregards the configured health probe’s response and always allows existing connections to persist to the backend instance.|
+| **Up**         | Load balancer ignores the health probe and always considers the backend instance as eligible for new connections. | Load balancer disregards the configured health probe's response and always allows existing connections to persist to the backend instance.|
 | **Down**       | Load balancer ignores the health probe and doesn't allow new connections to the backend instance. | Load balancer ignores the health probe and existing connections are determined according to the following protocols: </br>TCP: Established TCP connections to the backend instance persists.</br>UDP: Existing UDP flows move to another healthy instance in the backend pool.</br> **Note**: This is similar to a [Probe Down behavior](load-balancer-custom-probe-overview.md#probe-down-behavior).   |
 | **None**       | Load balancer respects the health probe behavior. | Load balancer respects the health probe behavior. |
 
 > [!NOTE]
-> Load Balancer Health Probe Status metrics and Load Balancer’s Insights topology will reflect your configured admin state value changes.
+> Load Balancer Health Probe Status metrics and Load Balancer's Insights topology reflect your configured admin state value changes.
 
 ## Design considerations
 
 When deploying a load balancer with admin state, consider the following design considerations:
 
-- Admin state takes effect on a per backend pool instance basis
-  - In a scenario where a virtual machine instance is in more than one backend pool, the admin state applied on one backend pool doesn't affect the other backend pool.
-  - In a scenario where a backend pool is part of multiple load balancing rules, the admin state applied on the backend pool affects all associated load balancing rules. 
-- Admin state will only take effect when there's a health probe configured on the load balancing rules.      
+1. Admin state takes effect on a per backend pool instance basis
+   1. In a scenario where a virtual machine instance is in more than one backend pool, the admin state applied on one backend pool doesn't affect the other backend pool.
+   1. In a scenario where a backend pool is part of multiple load balancing rules, the admin state applied on the backend pool affects all associated load balancing rules. 
+1. Admin state will only take effect when there's a health probe configured on the load balancing rules.      
 
 ## Limitations
 
 When deploying a load balancer with admin state, consider the following limitations:
 
-- Admin state isn't supported with inbound NAT rule. 
-- Admin state isn't supported for nonprobed load balancing rules.
-- Admin state can't be configured during the creation of a NIC-based Load Balancer backend pool. 
+1. Admin state isn't supported with inbound NAT rule. 
+1. Admin state isn't supported for nonprobed load balancing rules.
+1. Admin state can't be configured during the creation of a NIC-based Load Balancer backend pool. 
 
 
 ## Next steps

articles/load-balancer/backend-pool-management.md

@@ -6,7 +6,7 @@ services: load-balancer
 author: mbender-ms
 ms.service: azure-load-balancer
 ms.topic: how-to
-ms.date: 06/26/2024
+ms.date: 01/07/2026
 ms.author: mbender 
 ms.custom: template-how-to, devx-track-azurepowershell, devx-track-azurecli, engagement-fy23
 # Customer intent: As a cloud administrator, I want to configure and manage backend pools for a load balancer by IP address and virtual network, so that I can ensure proper resource allocation and traffic distribution for my applications.
@@ -18,9 +18,9 @@ The backend pool is a critical component of the load balancer. The backend pool
 
 There are two ways of configuring a backend pool:
 
-* Network Interface Card (NIC)
+1. Network Interface Card (NIC)
 
-* IP address
+1. IP address
 
 To preallocate a backend pool with an IP address range that will contain virtual machines and Virtual Machine Scale Sets, configure the pool by IP address and virtual network ID.
 This article focuses on configuration of backend pools by IP addresses.
@@ -215,21 +215,21 @@ az vm create \
 ```
 
 ### Limitations
-  * IP based backends can only be used for Standard Load Balancers
-  * The backend resources must be in the same virtual network as the load balancer for IP based LBs
-  * IP-based load balancers backend instances must still be virtual machines or virtual machine scale sets. Attaching other PaaS services to the backend pool of an IP based Load Balancer is not supported. 
-  * A load balancer with IP based Backend Pool can’t function as a Private Link service
-  * [Private endpoint resources](../private-link/private-endpoint-overview.md) can't be placed in an IP based backend pool
-  * IP-based load balancers doesn't support ACI containers
-  * Load balancers or services such as Application Gateway can’t be placed in the backend pool of the load balancer
-  * Inbound NAT Rules can’t be specified by IP address
-  * You can configure IP based and NIC based backend pools for the same load balancer. You can’t create a single backend pool that mixes backed addresses targeted by NIC and IP addresses within the same pool.
-  * A virtual machine in the same virtual network as an internal load balancer can't access the frontend of the ILB and its backend VMs simultaneously.
-  * Internet routing preference IPs are currently not supported with IP based backend pools. Any Internet routing preference IPs in IP based backend pools will be billed and routed via the default Microsoft global network.
-  * Performing move-related operations on VNETs that are attached to IP-based backend pools is not supported
-  * If backend pools are constantly changing (due to the constant addition or removal of backend resources). This may cause reset signals sent back to the source from the backend resource. As a workaround, you can use retries.
-
->[!Important]
+  1. IP based backends can only be used for Standard Load Balancers
+  1. The backend resources must be in the same virtual network as the load balancer for IP based LBs
+  1. IP-based load balancers backend instances must still be virtual machines or virtual machine scale sets. Attaching other PaaS services to the backend pool of an IP based Load Balancer isn't supported. 
+  1. A load balancer with IP based Backend Pool can't function as a Private Link service
+  1. [Private endpoint resources](../private-link/private-endpoint-overview.md) can't be placed in an IP based backend pool
+  1. IP-based load balancers don't support ACI containers
+  1. Load balancers or services such as Application Gateway can't be placed in the backend pool of the load balancer
+  1. Inbound NAT Rules can't be specified by IP address
+  1. You can configure IP based and NIC based backend pools for the same load balancer. You can't create a single backend pool that mixes backed addresses targeted by NIC and IP addresses within the same pool.
+  1. A virtual machine in the same virtual network as an internal load balancer can't access the frontend of the ILB and its backend VMs simultaneously.
+  1. Internet routing preference IPs are currently not supported with IP based backend pools. Any Internet routing preference IPs in IP based backend pools will be billed and routed via the default Microsoft global network.
+  1. Performing move-related operations on VNETs that are attached to IP-based backend pools isn't supported
+  1. If backend pools are constantly changing (due to the constant addition or removal of backend resources). This can cause reset signals sent back to the source from the backend resource. As a workaround, you can use retries.
+
+> [!IMPORTANT]
 > When a backend pool is configured by IP address, it will behave as a Basic Load Balancer with default outbound enabled. For secure by default configuration and applications with demanding outbound needs, configure the backend pool by NIC.
 
 ## Next steps

articles/load-balancer/components.md

@@ -1,19 +1,20 @@
 ---
 title: Azure Load Balancer components
-description: Overview of Azure Load Balancer components.
+description: Understand Azure Load Balancer's key components and configurations to effectively manage traffic and maintain application reliability.
 services: load-balancer
 author: mbender-ms
 ms.service: azure-load-balancer
 ms.topic: concept-article
-ms.date: 06/18/2024
+ms.date: 01/07/2026
 ms.author: mbender
+ms.reviewer: mbender
 ms.custom: sfi-image-nochange
 # Customer intent: "As a cloud architect, I want to understand the components of Azure Load Balancer, so that I can configure it effectively to manage traffic distribution and ensure high availability for my applications."
 ---
 
 # Azure Load Balancer components
 
-Azure Load Balancer includes a few key components. These components can be configured in your subscription through the Azure portal, Azure CLI, Azure PowerShell, Resource Manager Templates or appropriate alternatives.
+Azure Load Balancer includes a few key components. These components can be configured in your subscription through the Azure portal, Azure CLI, Azure PowerShell, an Azure Resource Manager Template or appropriate alternatives.
 
 ## Frontend IP configuration <a name = "frontend-ip-configurations"></a>
 
@@ -30,21 +31,21 @@ The nature of the IP address determines the **type** of load balancer created. P
 | **Description** | A public load balancer maps the public IP and port of incoming traffic to the private IP and port of the VM. Load balancer maps traffic the other way around for the response traffic from the VM. You can distribute specific types of traffic across multiple VMs or services by applying load-balancing rules. For example, you can spread the load of web request traffic across multiple web servers.| An internal load balancer distributes traffic to resources that are inside a virtual network. Azure restricts access to the frontend IP addresses of a virtual network that are load balanced. Frontend IP addresses and virtual networks are never directly exposed to an internet endpoint, meaning an internal load balancer can't accept incoming traffic from the internet. Internal line-of-business applications run in Azure and are accessed from within Azure or from on-premises resources. |
 | **SKUs supported** | Basic, Standard | Basic, Standard |
 
-:::image type="content" source="media/load-balancer-overview/load-balancer.png" alt-text="Diagram depicts a load balancer directing traffic.":::
+:::image type="content" source="media/load-balancer-overview/load-balancer.png" alt-text="Screenshot of load balancer architecture diagram showing traffic distribution between frontend and backend components.":::
 
 Load balancer can have multiple frontend IPs. Learn more about [multiple frontends](load-balancer-multivip-overview.md).
 
 ## Backend pool
 
-The group of virtual machines or instances in a virtual machine scale set that is serving the incoming request. To scale cost-effectively to meet high volumes of incoming traffic, computing guidelines generally recommend adding more instances to the backend pool.
+The group of virtual machines or instances in a virtual machine scale set that's serving the incoming request. To scale cost-effectively to meet high volumes of incoming traffic, computing guidelines generally recommend adding more instances to the backend pool.
 
 Load balancer instantly reconfigures itself via automatic reconfiguration when you scale instances up or down. Adding or removing VMs from the backend pool reconfigures the load balancer without other operations. The scope of the backend pool is any virtual machine in a single virtual network. 
 
-Backend pools support addition of instances via [network interface or IP addresses](backend-pool-management.md). VMs do not need a public IP address in order to be attached to backend pool of a public load balancer. VMs can be attached to the backend pool of a load balancer even if they are in a stopped state. You can also configure multiple backend pools with different groups of instances to a single load balancer. By creating multiple load balancing rules, each targeting a different backend pool, you can configure traffic to distribute to different sets of backend resources based on the load balancer frontend port and protocol.
+Backend pools support addition of instances via [network interface or IP addresses](backend-pool-management.md). VMs don't need a public IP address in order to be attached to backend pool of a public load balancer. VMs can be attached to the backend pool of a load balancer even if they are in a stopped state. You can also configure multiple backend pools with different groups of instances to a single load balancer. By creating multiple load balancing rules, each targeting a different backend pool, you can configure traffic to distribute to different sets of backend resources based on the load balancer frontend port and protocol.
 
 ## Health probes
 
-A health probe is used to determine the health status of the instances in the backend pool. During load balancer creation, configure a health probe for the load balancer to use.  This health probe determines if an instance is healthy and can receive traffic.
+A health probe is used to determine the health status of the instances in the backend pool. During load balancer creation, configure a health probe for the load balancer to use. This health probe determines if an instance is healthy and can receive traffic.
 
 You can define the unhealthy threshold for your health probes. When a probe fails to respond, the load balancer stops sending new connections to the unhealthy instances. A probe failure doesn't affect existing connections. The connection continues until the application:
 
@@ -72,15 +73,15 @@ A load balancer rule configured with **'protocol - all and port - 0'** is known
 
 The load-balancing decision is made per flow. This action is based on the following five-tuple connection: 
 
-1. source IP address
-2. source port
-3. destination IP address
-4. destination port
-5. protocol
+- source IP address
+- source port
+- destination IP address
+- destination port
+- protocol
 
 The HA ports load-balancing rules help you with critical scenarios, such as high availability and scale for network virtual appliances (NVAs) inside virtual networks. The feature can help when a large number of ports must be load-balanced.
 
-:::image type="content" source="media/load-balancer-components/harules.png" alt-text="Diagram of Azure Load Balancer directing all frontend ports to three instances of all backend ports":::
+:::image type="content" source="media/load-balancer-components/harules.png" alt-text="Screenshot of Azure Load Balancer HA ports configuration diagram showing frontend ports directing to backend instances.":::
 
 *Figure: HA Ports rules*
 
@@ -102,7 +103,7 @@ Learn more about [outbound connections and rules](load-balancer-outbound-connect
 
 Basic load balancer doesn't support outbound rules.
 
-:::image type="content" source="./media/load-balancer-components/outbound-rules.png" alt-text="Outbound rule reference diagram" border="false":::
+:::image type="content" source="./media/load-balancer-components/outbound-rules.png" alt-text="Screenshot of outbound rule configuration diagram showing NAT translation for backend pool instances." border="false":::
 
 *Figure: Outbound rules*
 
@@ -112,9 +113,9 @@ Basic load balancer doesn't support outbound rules.
 - Load balancer provides load balancing and port forwarding for specific TCP or UDP protocols. Load-balancing rules and inbound NAT rules support TCP and UDP, but not other IP protocols including ICMP.
 - Load Balancer backend pool can't consist of a [Private Endpoint](../private-link/private-endpoint-overview.md).
 - Outbound flow from a backend VM to a frontend of an internal Load Balancer will fail.
-- A load balancer rule can't span two virtual networks. All load balancer frontends and their backend instances must be in a single virtual network.  
+- A load balancer rule can't span two virtual networks. All load balancer frontends and their backend instances must be in a single virtual network. 
 - Forwarding IP fragments isn't supported on load-balancing rules. IP fragmentation of UDP and TCP packets isn't supported on load-balancing rules. 
-- You can only have one Public Load Balancer (NIC based) and one internal Load Balancer (NIC based) per availability set. However, this constraint doesn't apply to IP-based load balancers.  
+- You can only have one Public Load Balancer (NIC based) and one internal Load Balancer (NIC based) per availability set. However, this constraint doesn't apply to IP-based load balancers. 
 
 ## Next step