Multi Level Cluster
A cluster which has different regions is called Multi-Level Cluster where each region has its own origin for a stream. Ant Media Server can be scaled in different physical locations. You can set the node group parameter of the servers to create regions. Still you can make all nodes be in the same region by setting all node group parameters with the same value or using it with default. But separating the nodes into regions has some advantages in performance. Because each region will have their own origin node for a stream and the edges in a region will pull the stream from the origin of their region.
Lets clarify the the case with an example scenario.
- Publisher starts a stream and it is assigned to the Origin1 in the Region1.
- Lets say, Player1 who is closed to Region1 requests to play the stream.
- Player1 is assigned to Edge11 in Region1.
- Since the Origin1 is the origin of the stream, Edge11 will pull stream from Origin1.
- Until now, the scenario is one region cluster.
- Lets say, Player2 who is closed to Region2 requests to play the stream.
- Player2 is assigned to Edge21 in Region2.
- Edge21 checks the origin of the stream. Since it is not in its own region (Region2) it is assigned as the secondary origin for that stream in Region2. It pulls the stream from the Origin1 (main origin) in Region1. Also it is still an edge server so it servers the stream to Player2.
- Lets say, Player3 who is closed to Region2 requests to play the stream.
- Player3 is assigned to Edge22 in Region2.
- Edge22 checks the origin of the stream. Since Edge21 is a secondary origin for the stream, it pulls the stream from Edge21 and serves to Player3.
You can set the node group (or region) of a server in 2 ways:
You can set it as modeGroup=GROUP_NAME in conf/red5.properties file.
You can set it by calling POST Method AMS_URL/rest/changeServerSettings and passing node group in JSON format as follows.
{"nodeGroup":"GROUP_NAME"}
You should configure the Load Balancer to forward Publish and Play requests to the best region. If you have a global cluster in different geolocations,you should have a Load Balancer like Route53.