1. First thing you'll do is login to the New Control Panel, select Load Balancers from the list at the top, and then select Create Load Balancer.

Alternate Titles: “Load Balancer”

Author: Muhammad Zeeshan Bhatti [LPI, VCP, OCP (DBA), MCSA, SUSE CLA,] (http://zeeshanbhatti.com) ([email protected])

Load Balancer?

Mission critical web-based applications and workloads require an HA, or High Availability, solution. Load balancing distributes workloads across two or more servers, network links, and other resources to maximize throughput, minimize response time, and avoid overload. Rackspace Cloud Load Balancers allow customers to quickly load balance multiple Cloud Servers or external servers for optimal resource utilization.

Setting up a Load Balancer

1. First thing you'll do is login to the New Control Panel, select Load Balancers from the list at the top, and then select Create Load Balancer.

2. Next, under Identification you'll give a name to your Load Balancer. This can be any name you like.

3. Next under Configuration, you'll choose between three different choices for your Virtual IP.

 Public - Setting your VIP type to Public would allow any two servers with public IP addresses to be load balanced. These can be nodes outside of the Rackspace network, but please be aware that standard bandwidth rates will apply.

 Shared Virtual IP - Use this option if you wish to load balance multiple services on different ports while using the same virtual IP address.

 On the private Rackspace network - This is the best option for load-balancing two Cloud Servers, as it allows the load-balancing traffic to run on the Rackspace Cloud Internal Network, or Service Net. This option has two distinct advantages; the rate limit is double what the rate limit is on the public interface, and all traffic on the Service Net between Cloud Servers is not charged for bandwidth.

4. Next, choose the Protocol and Port to which best suits your needs. Your Port will adjust to the Protocol you select, but you may also edit this portion yourself. (See Choosing the Right Protocol for more

information about the protocols you can choose when configuring a Cloud Load Balancer.)

5. You'll then choose the Algorithm for your Load Balancer to which best fits your needs.

Note: this is a very important attribute to set, especially as your Load Balancer implementation gets more complex. Each algorithm has an explanation for how it assigns traffic. In most cases, the Random, Round

Robin, or Least Connections algorithms will be sufficient when load-balancing two identical servers for increased web traffic. If your servers are unequal in size or resources, you should take a look at using weighted algorithms to favor your servers with more resources.

6. Next, select the region you'd like your load balancer to be created in.

Note: when selecting a region, consider the location of the backend nodes you want to load balance and provision your load balancer in a region that is geographically as close to your backend nodes as possible.

7. And lastly, you can select from options on how you'd like to set your Load Balancer to operate on one or more of your Cloud Servers, or on one or more External Nodes. Select Create Load Balancer and after your load balancer is finished building, you may view a summary of the Load Balancer you created.

Note: To add an External Node to be load-balanced, you must enter the IP address and set the port of the service that you want load-balanced (usually port 80 for HTTP traffic). Then, you can either Enable or Disable the load-balancing service on your external node directly through the Control Panel. Additional configuration options

 Active Health Monitor - In addition to the default passive health monitor check, active health monitoring uses synthetic transaction monitoring to inspect an HTTP response code and body content to determine if the application or site is healthy.

 Advanced Access Control - Easily manage who can and can’t access the services that are exposed via the load balancer.

 Session Persistence - If you are load balancing HTTP traffic, the session persistence feature utilizes an HTTP cookie to ensure subsequent requests are directed to the same node in your load balancer pool.

 Connection Logging - To simplify log management, the Connection Logging feature allows for Apache-style access logs (for HTTP-based protocol traffic) or connection and transfer logging (for all other traffic) to your Cloud Files™ account. If you need raw data in one place for performance tuning or web analytics, logs are sorted, aggregated, and delivered to Cloud Files.

Archway Lowe’s Cloud load balancer Settings

It is capable of consistently handling 20,000 concurrent connections with support for periodic spikes estimated at up to 100,000 concurrent connections. Because Cloud Load Balancers are implemented in a multi-tenant environment, estimates are not guaranteed and might vary depending on the number of concurrent connections that other customer load balancers are processing.

Caching on Load Balancer is also enabled now, this will further improve the load handling and response time of environment.

Cloud Load Balancer Details

Selected Algorithm: Least Connections - Favors nodes with the least number of current connections.

Other available but not configured algorithms are following, only one algorithm can be selected at a time.

 Caching Round Robin - All nodes are treated equally and assigned requests in the order they are listed.

 Weighted Round Robin - Just like Round Robin but with the ability to favor individual nodes and assign them more connections based on a "Weight"

 Random - All nodes treated equally and assigned requests with no regard to the order that they are listed

 Weighted Least Connections - Like Least Connections but with the ability to favor individual nodes and assign them more connections based on a "Weight"details

Content Cashing

1. The maximum file size per cached item is 2 MB.

2. Cache life Up to 10 minutes, depending on the load and amount of traffic being handled by the load balancer host.

3. If a cached file is requested shortly before it will expire, the load balancer will retrieve a new copy of the file early to prevent the file from being uncached during a period of heavy traffic.

4. Nodes do not share cache, each node has its own cache, separate from other load-balanced nodes.

5. Following file extensions are cached:

 png  .gif  .jpg  .jpeg  .ico  .wav  .mp3  .flv  .mpeg  .js  .css  .mp4  .swf

6. Set the Cache-Control header on web server to no-cache for requests for the file types you don’t want cached.