Upgrade process for ServerLink with high-availability clusters

Stop the Web server (Apache) on all servers in the primary cluster and the disaster recovery (DR) cluster.
Stop ServerLink in the DR server. (Only one server will have ServerLink service running.)
Upgrade the MongoDB cluster in the primary cluster.
1. Enter one of the following commands to check the status of the cluster. Replace IP with your Mongo bind IP.
  On Windows:
```
cd C:\xampp\mongodb\bin
mongosh --host IP 
```
  On Linux:
```
mongosh  --host IP 
```
  On Windows or Linux, then run:
```
rs.status()
```
  To confirm that all nodes are in sync, check if their timestamps are the same.
2. Upgrade one of the secondary servers.
3. Upgrade each secondary server.
4. Upgrade the primary server..
5. Check the status of the cluster using the commands in 3a.
Upgrade the Web nodes in the primary cluster.
Upgrade Solr Server in the primary cluster
Follow steps 3 to 5 for the DR cluster.
Start all services.
Start ServerLink in the DR server