MTAS Scaling Management
MTAS

Contents

1Understanding Scaling Management
1.1Key Scaling Management Concepts

2
Basic Scaling Management Operations

1   Understanding Scaling Management

1.1   Key Scaling Management Concepts

The term scaling refers to the scalability of the system, which is provided by multiple instances to distribute the load in parallel for having the capacity needed.

The following terms are used:

Node Refers to a compute resource and can be a physical hardware blade or a virtual machine (VM) instantiation.
Fixed Domain The set of nodes that cannot be subject of a scaling operation. The fixed domain of MTAS consists of SC-1 and SC-2 nodes permanently. The domain cannot be changed.
Scaling Domain The set of nodes that can be subject of a scaling operation. MTAS scaling domain consists of all traffic nodes (PL-3, PL-4, PL-5 ... PL-N).

The PL-3 and PL-4 nodes are not scalable; even though PL-3 and PL-4 nodes are considered to be part of the scaling domain, they cannot be scaled in.

Traffic Handling: The scaling operation involves planned reconfiguration of distribution units. This activity is performed in the quickest possible manner with high priority, hence load regulation-related alarms can appear during scaling operation. Such alarms are not expected to be present for longer time than 2–4 seconds. The effect is minimal on traffic handling capability.

1.1.1   Auto Scale-Out

Auto Scale-Out is an operation when one or more new compute resources are launched, see Figure 1. The system automatically detects, configures, and brings up the nodes as a member of the scaling domain of the cluster. See Figure 2 for an example when one new compute node is added to the cluster.

Figure 1   New Compute Resource Spawned and Available

Figure 2   After Auto Scale-Out New Resource Is Added to Cluster

1.1.2   Graceful Scale-In

Graceful Scale-In is an operation where one or more compute resources, part of the scaling domain of the cluster (see Figure 3) are removed from the cluster (see Figure 4) to free up resources.

Figure 3   Node Named PL-(N-1) Is Part of Cluster

Figure 4   Node Named PL-(N-1) Is Removed from Cluster and Its Resources Can Be Released

Note:  
The Graceful Scale-In operation can be rejected by the cluster if, according to the automatic estimation of the system, the target size of the cluster does not have the memory resources to serve the needed memory capabilities for the ongoing traffic.

1.1.3   Forceful Scale-In

Forceful Scale-In is, similarly to Graceful Scale-In, an operation to remove one or more nodes from the scaling domain of the cluster. The only difference is that in this case, the node is not available (see Figure 5) either because it already freed up its resources or because of a failure. Therefore the removal is only an administrative operation, see Figure 6.

Figure 5   Node Named PL-(N-1) in the Cluster Scaling Domain Is Unavailable

Figure 6   Node Named PL-(N-1) Is Removed Administratively from Cluster

2   Basic Scaling Management Operations

Scaling Management is accessed using NETCONF or the Ericsson Command-Line Interface (ECLI) to manipulate the Management Information Base (MIB).

The following operations can be performed by the user and are described in Operating Instructions:

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