Indexing Shard Failure Call Flow

This section describes how the failover happens when two index replicas that belong to the same shard are down or unavailable.

The indexing shard failure is an example of two points-of-failure scenario where the two replicas reside on different virtual machines or hosts.

The PCF REST endpoint and PCF Engine redirect the traffic to the secondary CDL endpoint site (Site 2) based on the highest rating when the primary CDL site (Site 1) is unavailable.
Indexing Shard Failure Call Flow
Indexing Shard Failure Call Flow Description

Step

Description

1

In the Site 1 environment, index replica 1 and replica 2 for a configured shard has failed or unavailable. Since both the replicas for the shard are unavailable, the CDL endpoint in Site 1 is shut down and all the subsequent requests are directed to the CDL endpoint on Site 2.

In the Site 1 environment, the SMF sends a Create Request to PCF REST endpoint over the N7 interface.

2

After receiving the request, the PCF REST endpoint forwards the Create Request to the PCF Engine.

3

The PCF Engine attempts to reach the CDL endpoint to send the Session Create Request. However, the CDL endpoint is unreachable.

The PCF Engine sorts the CDL points across Site 1 and Site 2 to recognize the endpoint with the highest rating or priority.

4

The Create Request is evaluated in the stored session and the PCF Engine forwards the request to the CDL endpoint residing in Site 2.

5

After the call request is successful, the PCF Engine notifies the Success Message to the PCF REST endpoint.

6

The PCF REST endpoint forwards the Success Message to the SMF.