High Availability Load Balancing

HALB (High Availability Load Balancing) is a software solution that sits between the user and Parallels 2X gateways. Many HALB appliances can run simultaneously, one acting as the master and the others as slaves. The higher the number of HALB appliances available, the lower the probability that users will experience downtime. Master and slave appliances share a common or virtual IP, also known as VIP. Should the master HALB appliance fail, a slave is promoted to master and takes its place seamlessly without affecting the end user's connection.

Setting up HALB is a 2 stage process; HALB appliance installation and configuration followed by adding an HALB appliance from the Parallels 2X RAS console.

Hypervisor Prerequisites

Before configuring HALB from the Parallels 2X RAS console, first import a HALB appliance to either of the following Hypervisor platforms; Microsoft Hyper-V,  Virtual Box or VMware. An appliance is a pre-configured virtual machine (including the operating system and other relevant settings).

Virtualbox/ VMware

For Virtual Box or VMware this appliance should be imported with either the OVA or zipped VMDK appliance file obtained from the 2X Website.

If deployed via the OVA file, the VM is applied with machine specifications already configured. Alternatively deployment via the VMDK file deploys the VM without pre-configured specifications. The minimum specifications for this VM are outlined below:

  1. 1 CPU
  2. 256 mb RAM
  3. 1 Network Card

Microsoft Hyper-V

For Microsoft Hyper-V this appliance should be imported with the VDH file obtained from the 2X Website. 

HALB Appliance Installation and Configuration

The HALB appliance should be imported on a Hypervisor running on a separate machine connected to the same local network as Parallels 2X RAS. Import the HALB appliance on a supported Hypervisor according to the procedure below.

  1. Import the HALB appliance file from the virtualization platform’s management console.
  2. Power up (boot) the new appliance to display the HALB - First boot configuration screen.
  3. Adjust the network settings (if necessary) and click ‘Apply’ to continue.
  4. The Configuration Console is displayed and the HALB appliance is ready to be added to a Parallels 2X RAS farm.

Note: Repeat the process above to create multiple HALB appliances.

Adding an HALB Appliance from Parallels 2X RAS

Subsequent to the HALB appliance installation, proceed to configure the appliance from a  Parallels 2X Remote Application Server farm according to the steps below:

Enabling HALB

  1. Log in to the Parallels 2X RAS Console > Farm > HALB. Enable the HALB check box and Configure the fields below:
  • Virtual IP:Enter an available IP address in the  Virtual IP field. This is the IP that the clients will connect to. This will also be the floating IP used by this and other HALB appliances.
  • Subnet Mask: Enter the appropriate network mask.
  • Maximum Sessions per device: Set the maximum number simultaneous connections allowed.

Select Gateways which will be Load Balanced

  1. Enable ‘LB Gateway Payload’ to load balance normal gateway connections and click ‘Configure’ to bring up the ‘HALB Configuration’ window.
  • Port: Enter the port that will be used by HALB appliances to forward traffic to gateways (the port configured on the gateway).
  • Select the gateways that the HALB appliance will load balance.

Click ‘OK’ to apply the settings.

Select Gateways which will be Load Balanced

  1. If required, enable ‘LB SSL Payload’ to load balance SSL connections and click ‘Configure’ to bring up the ‘HALB Configuration’ window.
  • Port: Enter the port that will be used by HALB appliances to forward traffic gateways (443 by default).
  • Mode: Select either Passthrough  or SSL Offloading to define where the SSL decryption process is performed.  By default, the SSL connections are tunnelled directly to the gateways (referred to as passthrough) where the SSL decryption process is performed.
  • Select the gateways that the HALB appliance will load balance.

Setting up HALB

Configure SSL

To set the SSL decryption process to be performed on the HALB appliance, select ‘SSL Offloading’ Mode and click ‘Configure’. This mode requires an SSL certificate installed on the HALB appliances.  Fill in the below to generate a new certificate:

  • Allow only strong ciphers: (Optional) Enable to allow the usage of certificates using strong encryption algorithms.
  • Accepted SSL Versions: Select to accept SSL versions with an encryption strength of your choice.

Click ‘Generate new certificate’ and enter the required details. The  ‘Private Key file and ‘Certificate file’ are automatically populated

Generate Certificate Request

Alternatively click ‘Generate certificate request’, fill in the details required and click ‘Save’ to bring up the certificate request window shown above. Click “Copy” to copy the request.

This certificate request should be sent to a certificate authority. Once you receive the SSL certificate from the certificate authority click on the “Import public key“, browse for the certificate file containing the public key and click Open.

Add HALB Appliance

  1. Next, proceed to add HALB appliances that will be managed by this farm. Click the green plus icon shown above to bring up the ‘Add HALB Devices window shown below.

Add Detected or Enter HALB Appliance IP Address Manually

Parallels 2X RAS is capable of detecting HALB appliances over the network and display them, as a list. Selecting detected HALB appliances from this list is the preferred method for adding new appliances.  If for some reason, the appliance cannot be detected, you can also add the HALB appliance manually by specifying the appliance IP in the ‘IP Address field. Click ‘OKto apply the config.

  1. After the ‘OK’ button is pressed, the appliance is initialized and added to the list.

Finalize HALB Appliance Configuration

  1. Finally, click “Apply” for configuration to be applied to all added HALB appliances.

Note: For the full Parallels 2X recomended step by step procedure, please review the following guide: http://www.2x.com/support/ras/deploy-and-configure-halb-appliance/