Nutanix Controller VM (CVM) is the brain of a Nutanix Cluster running the Nutanix AOS software to form a highly-resilient cluster comprised of 3 or more nodes.
Nutanix CVM offers rich data services, virtual machine management and hosting services, replication services - while ensuring all data and metadata is checksummed to ensure data consistency and integrity.
Nutanix CVM communicates over a IP network to all other CVMs and Hosts in the cluster. Thus, changing the CVM IP Address should be planned carefully with all the following and any environment specific points:
- CVM and Hypervisor Host are required to be in the same subnet (192.168.5.x)
- Hypervisor host can be multi-homed, but point - (i) is mandatory
- IPMI subnet should be reachable to and from the CVM
- Cluster Virtual IP Address
- iSCSI Data Services IP (used by Volumes, Files, Objects, Karbon, LEAP)
- Network Segmentation check (Backplane traffic)
- Remote Sites and any on-going replication
- Guest VM downtime (this is required for Re-IP activity)
- Always run
ncc health_checks run_allto ensure cluster is in a optimal state - Ensure NTP will be reachable from new subnet
- Document existing and new IP addresses, subnet masks, gateways, hostnames
- Ensure network reachability for remote sites from new network addresses
Note: All Controller VMs and hypervisor hosts must be on the same subnet. The hypervisor can be multi-homed provided that one interface is on the same subnet as the Controller VM.
Once the above points are taken care of, you can then proceed to change the IP addresses of the CVMs in your environment.
CVM IP Address change can be done via external_ip_reconfig script.
Do not use the external IP address reconfiguration script (external_ip_reconfig) if you are using the network segmentation feature on your cluster and you want to change the IP addresses of the backplane (eth2) interface. See the Reconfiguring the Backplane Network topic in the Prism Web Console Guide for instructions about how to change the IP addresses of the backplane (eth2) interface.
Steps to change the CVM IP Addresses
A step by step guide is provided with AOS Advanced Admin guide on the Nutanix Portal, please follow the details and steps provided at the following link:
CHANGING THE CONTROLLER VM IP ADDRESSES IN YOUR NUTANIX CLUSTER
TIP : You can also utilise the IP Address change worksheet template to document existing and new details - IP Address Change Worksheet Template
If you run into any problems, following Nutanix KB article also outlines some troubleshooting steps, along with CVM IP Address Change steps for different AOS versions.