My.VPSLink.com Load Balancing Service

This document describes basic operation of the My.VPSLink.com Load Balancing Service - see the related links section and advanced configuration for HAProxy configuration recommendations.

---

---

Load Balancing Service

The VPSLink Load Balancing Service is based on HAProxy "The Reliable, High Performance TCP/HTTP Load Balancer".

We highly recommend that you review the HAProxy Configuration Manual to get the most out of this advanced service - where possible, HAProxy naming conventions have been applied to our load balancing service interface.

Setup

Access the service from the My.VPSLink.com Control Center:

1. Log in at https://my.vpslink.com/
2. Mouse-over the Services drop-down menu
3. Select Load Balancing

Requirements

During the beta-testing period, your account will automatically include access to the VPSLink Load Balancing Service.

You will need at least two active VPS subscriptions to use the load balancing service.

Server Groups

You will be assigned a load balancer IP address for each load balancing service subscription on your account (during the beta testing period you will automatically have one assigned IP address on the load balancer).

Each load balancer IP can support a server group on each available port. You may add, edit, enable or disable, and remove server groups from the Dashboard page.

Server Group Configuration

The following configuration options are available when adding or modifying a server group:

• Enabled - Enable or disable a server group and all servers associated with the group
• Load Balancer IP - Load balancer IP for this server group
• Load Balancer Port - Set to the port for the service which is being balanced
• Domain - Label for the site being load balanced
• Load Balancing Mode - Specify the level at which load balancing will operate:
  • TCP - Transport-level - support for all TCP-based services
  • HTTP - Application-level - advanced support for clustered webservers
• Load Balancing Algorithm - Specify how the load balancer will distribute traffic:
  • Round Robin - Traffic is distributed evenly between servers based upon each server's Weight configuration (see Server Configuration for details)
  • Least Connections - Traffic is directed to the server with the least connections at the time the request is issued
  • Source - A hash of the client's IP address is generated and used to determine which server the client's traffic is persistently directed to
• Client Timeout - Maximum length of time the load balancer will wait for a reply from a client before releasing the client connection

The following configuration options are available when the HTTP load balancing mode is selected:

• Statistics URI - URI served by at the load balancer IP for usage statistics
• Statistics Username - Username required for authentication when viewing usage statistics
• Statistics Password - Password required for authentication when viewing usage statistics
• HTTP Cookie Name - Name of the cookie set by the load balancer to maintain persistence across HTTP requests (this cookie will contain the unique identifier of the server which is servicing the client's requests)

Enable a Server Group

From the Dashboard page click the Activate Server Group icon for the server group to enable the server group and all associated servers.

Delete a Server Group

From the Dashboard navigate to the Edit Server Group page and click the Delete icon.

Servers

Server configurations allow you to direct which VPS subscriptions the load balancer directs traffic to and specify how the load balancer distributes load across your VPS subscriptions.

Note: Deleting a server configuration through the load balancing application will prevent the load balancer from directing traffic to your VPS, however, no changes will be made to your VPS filesystem or billing status.

Server Configuration

• Enabled - Enable or disable traffic to this server
• Server IP - VPS IP address to accept load balanced traffic
• Server Port - VPS port to accept load balanced traffic
• Backup Only - If selected this server will only receive traffic when servers which are not marked Backup Only are down
• Fail Count - Number of failed health checks completed before server is considered "dead" and temporarily removed from load balancing pool
• Default Check Interval - Default health check interval
• Transition Check Interval - Special health check interval used when a server appears to be going up or coming down
• Rise Count - Number of successful health checks completed before server is considered "alive" and returned to load balancing pool
• Down Check Interval - Special health check interval used when server has been temporarily removed from load-balancing pool and is considered "dead"
• Max. Active Connections - Maximum number of concurrent connections allowed for this server (0 = unlimited)
• Max. Queued Connections - Maximum number of connections allowed in load balancer queue for this server (0 = unlimited)
• Weight - Used to determine the relative amount of load which this server will receive with Round Robin algorithm
  • 0 - Do not participate in load-balancing (accepts existing persistent connections)
  • 1 - (default) Participate in load balancing, accept minimal load if other servers have higher weights
  • 256 - Participate in load balancing, accept maximum load for server group

Enable a Server

If server group is disabled: from the Dashboard page click the Activate Server Group icon for the server group to enable the server group and all associated servers.

If server group is active but server is disabled: navigate to the Edit Server page and switch the Enabled option to "Enabled" then click Update >>

Delete a Server

Navigate to the Edit Server page and click the Delete icon.

Related Links

• My.VPSLink.com Load Balancing Service (Advanced Configuration)
• HAProxy 1.3 Documentation
• HAProxy Configuration Demo at 37signals
• High Performance Computing: Coding In the Cloud at Dr. Dobb's