You can use static IP addresses and FQDN to avoid risk during backup, restoration, and disaster recovery operations.

Static IP Addresses for vRealize Log Insight Cluster Nodes and Load Balancer

When you use static IP addresses for all nodes in a vRealize Log Insight cluster, you eliminate the need to update the IP addresses of the cluster nodes when the IP addresses change.

vRealize Log Insight includes all node IP addresses in each cluster node configuration file located at /storage/core/loginsight/config/loginsight-config.xml#<n>, where <n> is the largest number.

All products that integrate with vRealize Log Insight (ESXi, vSphere, vRealize Operations) use the cluster master node's fully qualified domain name (FQDN) or IP address as the syslog target. Those products might use the FQDN or IP address of the load balancer, if configured, as the syslog target. Static IP addresses reduce the risk of constantly updating the syslog target IP address in multiple locations.

Provide static IP addresses as well as optional virtual IP addresses for the load balancer.  When configuring an integrated load balancer, provide the optional FQDN for the virtual IP address. The FQDN will be used when an IP address is not reachable for any reason.

FQDN for vRealize Log Insight Cluster Nodes and Worker Node

When you use an FQDN for all nodes in the vRealize Log Insight cluster, you can save time on post-restoration and recovery configuration changes, assuming that the same FQDN can be resolved on the recovery site.

For the master node (load balancer when used), a fully resolvable FQDN is required. Otherwise, the ESXi hosts fail to feed the syslog messages to vRealize Log Insight or to any remote target. 

For system notifications, vRealize Log Insight uses FQDN host names, if available, instead of IP addresses.  

You can reasonably assume that only underlying IP addresses change post-backup and restoration or disaster recovery operations. Using FQDN eliminates the need to change the syslog target address (master node FQDN or internal load balancer FQDN) on all the external devices feeding logs to the vRealize Log Insight cluster.

With vRealize Log Insight 2.5, you must update the configuration file located at /storage/core/loginsight/config/loginsight-config.xml#<n>, where <n> is the largest number. You must replace the worker node IP address with the new IP address used for the restored nodes. The FQDN is not used for worker node addresses in the configuration file. You make this change only on the master node to synchronize the changes with all worker nodes.

Verify that join requests from a vRealize Log Insight worker node use the FQDN of the vRealize Log Insight master node.

Beginning in vRealize Log Insight 2.5, the master node host value in the configuration file on each of the nodes, located at /storage/core/loginsight/config/loginsight-config.xml#<n>, is based on the value used by the first worker node sending a join request. Using the FQDN of the master node for the join request prevents making any manual changes to the master node host value post-disaster recovery. Otherwise, the worker nodes cannot rejoin the master node until the master node host name is updated in the configuration files on all restored cluster nodes.