Slave node is not marked as 'Can be imported' in Cluster import in SolusVM 2

Symptoms 

Slave node is not marked as 'Can be imported' at SolusVM 2 > Cluster Imports > Import

Cause

Public SSH key used for Cluster Import is not installed on the corresponding SolusVM 1 slave node

Resolution

1. Connect to SolusVM 1 Slave node via SSH
2. Add SSH public key used for the Cluster Import to /root/.ssh/authorized_keys