Configure a load balancer

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Mission-critical web-based applications and workloads require a high availability (HA) 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 enable you to quickly load balance multiple cloud servers or external servers for optimal resource utilization.

This article provides instructions for setting up and configuring a load balancer in the Rackspace Cloud.

Set up a load balancer

Use the following steps to set up a load balancer:

Log in to the Cloud Control Pane [1].
In the top navigation bar, click Select a Product > Rackspace Cloud.
Select Networking > Load Balancers.

The Cloud Load Balancers page appears.
Click Create Load Balancer.
In the Identification section, enter a name for the new load balancer and select the region.
In the Configuration section, select one of the following choices for Virtual IP:
- Accessible on the Public Internet: Setting your virtual IP type to public enables any two servers with public Internet Protocol (IP) addresses to be load balanced. While these servers can be nodes outside of the Rackspace network, be aware that standard bandwidth rates apply.
- On the Rackspace Service Network: This is the best option for load balancing two cloud servers because it enables the load-balancing traffic to run on the Rackspace Cloud internal network or ServiceNet. This option has two advantages: the rate limit on ServiceNet is double the rate limit on the public interface, and traffic between cloud servers has no charge for bandwidth.
Choose the protocol and port that you want to use. The port adjusts to the protocol that you select, but you can also manually edit the port.

Note: For more information about the protocols that you can choose when configuring a load balancer, see Choosing the Right Protocol.
Choose the appropriate algorithm for your load balancer.

Note: This is an important attribute to set, especially as your
load balancer implementation becomes more complex. In most cases, the
Random, Round Robin, or Least Connections algorithm is sufficient when
you are load balancing two identical servers for increased web traffic. If
your servers are unequal in size or resources, consider using weighted
algorithms to favor the servers that have more resources.
In the Add Nodes section, click Add Cloud Servers to set your load
balancer to operate on one or more of your cloud servers.
To add one or more external nodes, click Add External Node, then enter
the IP address and port (usually port 80 for HTTP traffic) of the service
that you want to load balance. You can then enable or disable the
load-balancing service on your external node directly through the Control
Panel.

Note: The only domain names that you can use are host names that are
associated with Cloud Database host names.
Click Create Load Balancer.

After your load balancer builds, you can view a summary of it.

Additional configuration options

You can also configure the following options on the details page for the load
balancer:

Health Monitoring: 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.
Access Control: This setting enables you to easily manage who can and
can't access the services that the load balancer exposes.
Session Persistence: If you're load balancing HTTP traffic, this feature
uses an HTTP cookie that directs subsequent requests to the same node in
your load balancer pool.
Logging: For log management simplification, the logging feature supports
both Apache-style access logs (for HTTP-based protocol traffic) and
connection and transfer logging (for all other traffic) to your Cloud Files
account. Logs are sorted, aggregated, and delivered to Cloud Files so that
you have raw data in a single place that you can use for performance tuning
or web analytics.
Connection Throttling: Connection throttling limits the number of
simultaneous connections that are allowed from each IP address. This feature
helps prevent malicious or abusive traffic from reaching your server and its
installed applications.
Content Caching: Content caching improves website performance by
temporarily storing data that was recently accessed. While the data is
cached, the load balancer serves the data, instead of making another query
to a web server behind it. This approach reduces response times for those
requests and reduces the load on the web server. This feature works well if
you have files that rarely change, such as static content and images.
Secure Traffic (SSL): SSL enables you to secure the traffic on your
servers with an SSL certificate and private key.
HTTPS Redirect: This feature enables you to configure a load balancer
to redirect non-SSL HTTP traffic to SSL-secured HTTPS traffic. To
use this feature and enable HTTPS redirects, you must configure your load
balancers with SSL over port 443 and Only Allow Secure Traffic.
Logging: When logging is enabled, the service processes load balancer
access log files every hour and stores them in Cloud Files.
Error Page: The service presents visitors with a Default Message
error page when a load balancer is unable to pass traffic to the nodes
behind it. However, this feature has a Custom Error Page option that
enables you to use your own custom error page.

Pricing

The cost for each load balancer is based on an hourly rate, plus
the number of concurrent connections, plus bandwidth. You can view pricing
details on the following product pages for Cloud Load Balancers:

Next steps: Cloud Files and the Content Delivery Network

Updated about 1 year ago