Load Balancers

A load balancer is a device that distributes incoming network traffic amongst multiple back-end systems. These back-end systems are called the nodes of the load balancer.

Getting started

1. Instantiate a Rackspace client.

use OpenCloud\Rackspace;

$client = new Rackspace(Rackspace::US_IDENTITY_ENDPOINT, array(
    'username' => '<YOUR RACKSPACE CLOUD ACCOUNT USERNAME'>,
    'apiKey'   => '<YOUR RACKSPACE CLOUD ACCOUNT API KEY>'
));

2. Retrieve the server instances you want to add as nodes of the load balancer.

$computeService = $client->computeService('cloudServersOpenStack', 'DFW');

$serverOne = $computeService->server('e836fc4e-056d-4447-a80e-fefcaa640216');
$serverTwo = $computeService->server('5399cd36-a23f-41a6-bdf7-20902aec0e74');

The example above uses two server instances that have already been created. It retrieves the server instances using their IDs. See also: creating server instances.

3. Obtain a Load Balancer service object from the client.

This object will be used to first define the load balancer nodes and later create the load balancer itself.

$loadBalancerService = $client->loadBalancerService('cloudLoadBalancers', 'DFW');

4. Define a load balancer node for each server.

$loadBalancer = $loadBalancerService->loadBalancer();

$serverOneNode = $loadBalancer->node();
$serverOneNode->address = $serverOne->addresses->private[0]->addr;
$serverOneNode->port = 8080;
$serverOneNode->condition = 'ENABLED';

$serverTwoNode = $loadBalancer->node();
$serverTwoNode->address = $serverTwo->addresses->private[0]->addr;
$serverTwoNode->port = 8080;
$serverTwoNode->condition = 'ENABLED';

In the example above, each node runs a service that listens on port 8080. Further, each node will start out as ENABLED, which means it will be ready to receive network traffic from the load balancer as soon as it is created.

5. Create the load balancer with the two nodes.

$loadBalancer->addVirtualIp('PUBLIC');
$loadBalancer->create(array(
    'name' => 'My smart load balancer',
    'port' => 80,
    'protocol' => 'HTTP',
    'nodes' => array($serverOneNode, $serverTwoNode)
));

In the example above, the load balancer will have a virtual IP address accessible from the public Internet. Also notice that the port the load balancer listens on (80) does not need to match the ports of its nodes (8080).

Next steps

Once you have created a load balancer, there is a lot you can do with it. See the complete user guide for load balancers.