Clustering is a way for several servers to act as one. One InterWorx Control Panel server acts as the Director (aka Cluster Manager), and the other InterWorx servers are set as Nodes (Slaves). By default, the nodes mount the /home partition of the director, but using an external NFS device is also an option. When a web request is made, it will be load balanced across all of the servers, according to the IP-based load balanced policies.
What are the benefits of clustering?
The chief benefit of clustering is that that you have the resources of several servers working as one. You can use the load balancing policies to separate different services to different nodes in the cluster as well. The most common use for clustering is to combine the resources of several servers to power one or more popular and/or processor intensive sites, and to improve availability.
Are there any drawbacks of clustering?
Given the nature of clustering, there is some increased complexity vs. a single server solution. However, we work very hard to minimize this complexity to make the experience as painless as possible, and the benefits can more than make up for it.
Does InterWorx Control Panel support High Availability (HA) Clusters?
No, not at this time, however a future release will support this. There is no eta at this time, but stay tuned!
Will InterWorx Control Panel Clustering work with a NAT setup?
The clustering/load balancing setup for InterWorx Control Panel servers *will* work in NAT'd setup under the following conditions: You must use STATIC NAT, where there is a one-to-one correspondence between external and internal IP's.
You can use InterWorx Control Panel in an unclustered setup behind NAT (any NAT) without problems, but the clustered/load balanced version will require static NAT. Check out wikipedia for more information on NAT
Search for: “Basic NAT vs port number translation” and it gives a good description.
If we only had one public IP, could we setup a cluster service? Would the service run on private IPs? The setup would be with one public IP and behind it, imagine five servers doing load balancing and clustering. Would this be possible?
Yes, one public IP is fine.
With clustering, does each server need its own InterWorx license?
Yes, since each server (Cluster Manager and Node) has a copy of InterWorx Control Panel installed, each needs its own unlimited domain license.
Can I add and remove Nodes to the cluster transparently?
Yes. The end user will not see any difference, assuming the resource load on the cluster would not overwhelm the remaining nodes.