Load balancers distribute workloads across 2 or more servers, network links or other resources. This distribution maximizes throughput, minimizes response time and helps avoid overload. The following information discusses several available options with dedicated load balancers.
When you use your cloud servers to host an application that scales up and down (for example, the web tier of an application), it is important to have a method for adding and removing cloud servers from their associated load balancer pool(s). If you use an F5 BIG-IP Local Traffic Manager (LTM) with RackConnect, you can specify the load balancer pool name that a cloud server should be placed in when it is created. When you delete the cloud server, it will automatically be removed from the pool.
With RackConnect, there are two ways that you can automatically associate your cloud servers with one or more load balancer pools on your BIG-IP LTM:
Option 1 — Metadata: When creating a cloud server, use the metadata option to specify the pool or pools.
Metadata Key: RackConnectLBPool
Metadata Value: The exact name of the pool as defined on the load balancer. Use a semicolon separated list for more than one pool. In the following example, multiple metadata pool values are entered for the cloud server.
You can also specify the metadata values when you use the cloud servers API to create new cloud servers. View the API documentation for more details about how to use the API to enter metadata information for a cloud server: API Developer Guide: Set Metadata.
This is the method to use if you want Auto Scale to use RackConnect with F5 load balancers. Read more about this on the Auto Scale Tips and How To's page about cloud bursting.
Note: Rackspace reads metadata values only when a server is initially created, so changing the metadata values for a cloud server that is already deployed does not affect load balancer pool membership.
Option 2 — Name Match: Before you create your cloud servers, provide Rackspace with the preferred names and the pool(s) to associate with your cloud servers. Currently, you must configure this through a ticket request to your Support team.
Regardless of which option you select, consider the following requirements:
To get the name of one or more load balancer pools, contact your Support team.
The following diagram shows the path that inbound (and return) load balancer pool traffic follows to your cloud servers when you use an F5 BIG-IP load balancer with RackConnect:
The Brocade ADX can also be used as a load balancer that balances traffic between dedicated and cloud servers. In this case, the RackConnect Connected Device will be a Cisco ASA firewall and any traffic that needs to be load balanced to cloud servers will flow from the ADX to the firewall to the cloud servers.
The benefits of using a Brocade load balancer with RackConnect are as follows:
The limitations of using a Brocade load balancer with RackConnect are as follows:
The following diagram shows the path that inbound and return load balancer pool traffic follows to your cloud servers when you use a Brocade ADX load balancer with RackConnect:
If you have any questions about using Dedicated load balancers with RackConnect, contact your Support team.
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