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In a VPC, you can configure two types of load balancing—external LB and internal LB. External LB is nothing but a LB rule created to redirect the traffic received at a public IP of the VPC virtual router. The traffic is load balanced within a tier based on your configuration. Citrix NetScaler and VPC virtual router are supported for external LB. When you use internal LB service, traffic received at a tier is load balanced across different tiers within the VPC. For example, traffic reached at Web tier is redirected to Application tier. External load balancing devices are not supported for internal LB. The service is provided by a internal LB VM configured on the target tier.

A &PRODUCT; user or administrator may create load balancing rules that balance traffic received at a public IP to one or more VMs that belong to a network tier that provides load balancing service in a VPC. A user creates a rule, specifies an algorithm, and assigns the rule to a set of VMs within a VPC. Log in to the &PRODUCT; UI as an administrator or end user. In the left navigation, choose Network. In the Select view, select VPC. All the VPCs that you have created for the account is listed in the page. Click the Configure button of the VPC, for which you want to configure load balancing rules. The VPC page is displayed where all the tiers you created listed in a diagram. For each tier, the following options are displayed: Internal LB Public LB IP Static NAT Virtual Machines CIDR The following router information is displayed: Private Gateways Public IP Addresses Site-to-Site VPNs Network ACL Lists In the Router node, select Public IP Addresses. The IP Addresses page is displayed. Click the IP address for which you want to create the rule, then click the Configuration tab. In the Load Balancing node of the diagram, click View All. Select the tier to which you want to apply the rule. Specify the following: Name: A name for the load balancer rule. Public Port: The port that receives the incoming traffic to be balanced. Private Port: The port that the VMs will use to receive the traffic. Algorithm. Choose the load balancing algorithm you want &PRODUCT; to use. &PRODUCT; supports the following well-known algorithms: Round-robin Least connections Source Stickiness. (Optional) Click Configure and choose the algorithm for the stickiness policy. See Sticky Session Policies for Load Balancer Rules. Add VMs: Click Add VMs, then select two or more VMs that will divide the load of incoming traffic, and click Apply. The new load balancing rule appears in the list. You can repeat these steps to add more load balancing rules for this IP address.

&PRODUCT; supports sharing workload across different tiers within your VPC. Assume that multiple tiers are set up in your environment, such as Web tier and Application tier. Traffic to each tier is balanced on the VPC virtual router on the public side, as explained in . If you want the traffic coming from the Web tier to the Application tier to be balanced, use the internal load balancing feature offered by &PRODUCT;.

In this figure, a public LB rule is created for the public IP 72.52.125.10 with public port 80 and private port 81. The LB rule, created on the VPC virtual router, is applied on the traffic coming from the Internet to the VMs on the Web tier. On the Application tier two internal load balancing rules are created. An internal LB rule for the guest IP 10.10.10.4 with load balancer port 23 and instance port 25 is configured on the VM, InternalLBVM1. Another internal LB rule for the guest IP 10.10.10.4 with load balancer port 45 and instance port 46 is configured on the VM, InternalLBVM1. Another internal LB rule for the guest IP 10.10.10.6, with load balancer port 23 and instance port 25 is configured on the VM, InternalLBVM2. vpc-lb.png: Configuring internal LB for VPC

Create a network offering, as given in . Create an internal load balancing rule and apply, as given in .

To have internal LB support on VPC, create a network offering as follows: Log in to the &PRODUCT; UI as a user or admin. From the Select Offering drop-down, choose Network Offering. Click Add Network Offering. In the dialog, make the following choices: Name: Any desired name for the network offering. Description: A short description of the offering that can be displayed to users. Network Rate: Allowed data transfer rate in MB per second. Traffic Type: The type of network traffic that will be carried on the network. Guest Type: Choose whether the guest network is isolated or shared. Persistent: Indicate whether the guest network is persistent or not. The network that you can provision without having to deploy a VM on it is termed persistent network. VPC: This option indicate whether the guest network is Virtual Private Cloud-enabled. A Virtual Private Cloud (VPC) is a private, isolated part of &PRODUCT;. A VPC can have its own virtual network topology that resembles a traditional physical network. For more information on VPCs, see . Specify VLAN: (Isolated guest networks only) Indicate whether a VLAN should be specified when this offering is used. Supported Services: Select Load Balancer. Select InternalLbVM from the provider list. Load Balancer Type: Select Internal LB from the drop-down. System Offering: Choose the system service offering that you want virtual routers to use in this network. Conserve mode: Indicate whether to use conserve mode. In this mode, network resources are allocated only when the first virtual machine starts in the network. Click OK and the network offering is created.

Log in to the &PRODUCT; UI as an administrator or end user. In the left navigation, choose Network. In the Select view, select VPC. All the VPCs that you have created for the account is listed in the page. Locate the VPC for which you want to configure internal LB, then click Configure. The VPC page is displayed where all the tiers you created listed in a diagram. Locate the Tier for which you want to configure an internal LB rule, click Internal LB. In the Internal LB page, click Add Internal LB. In the dialog, specify the following: Name: A name for the load balancer rule. Description: A short description of the rule that can be displayed to users. Source IP Address: The source IP from which traffic originates. Typically, this is the IP of an instance on another tier within your VPC. Source Port: The port associated with the source IP. Traffic on this port is load balanced. Instance Port: The port of the internal LB VM. Algorithm. Choose the load balancing algorithm you want &PRODUCT; to use. &PRODUCT; supports the following well-known algorithms: Round-robin Least connections Source