When adding a new node to a Proxmox VE 9 cluster, you may encounter the error message:
pve1 has ring1_addr, but there is no interface number 1 configured
This issue is common when cluster nodes have multiple network links—for example, when using separate interfaces for management and cluster communication. In this guide, we’ll explain what causes this error, how to fix it, and best practices for setting up a reliable Proxmox cluster network.
Understanding the Error
Proxmox VE uses Corosync for cluster communication. Corosync relies on rings (network interfaces) to synchronize cluster data and maintain quorum.
Each ring corresponds to a network interface:
ring0_addr → primary cluster network (usually management)
ring1_addr → secondary network (redundant cluster link)
When you see the error:
…it means that the node you’re trying to join doesn’t have a matching network interface configuration (no ring1 network defined), while the existing cluster expects it.
Common Causes
Missing secondary network interface on the new node
Incorrect Corosync configuration (
/etc/pve/corosync.conf)Network mismatch between existing cluster nodes and the new node
Node added from a different network segment
Step-by-Step Troubleshooting
Step 1: Check Existing Cluster Corosync Configuration
On an existing cluster node, open the Corosync configuration file:
You’ll see something like:
Step 2: Verify Network Interfaces on the New Node
Run:
Make sure both networks exist and are reachable:
One for
ring0_addr(e.g., 192.168.122.x)One for
ring1_addr(e.g., 192.168.123.x)
If the second network (for ring1_addr) doesn’t exist, you’ll need to configure it first.
Step 3: Add Missing Network Interface on the New Node
You can do it either from command line or through Proxmox web interface – System – Network. Then retry joining the cluster.
root@pve3:~# pvecm add pve1 --link0 address=192.168.122.53 --link1=192.168.123.53
Please enter superuser (root) password for 'pve1': ********
Establishing API connection with host 'pve1'
The authenticity of host 'pve1' can't be established.
X509 SHA256 key fingerprint is D3:56:6E:A8:89:5B:0D:D1:86:66:B6:8C:B2:B2:3F:23:CE:44:F2:A5:75:19:F4:10:A9:A6:F4:32:37:35:12:8F.
Are you sure you want to continue connecting (yes/no)? yes
Login succeeded.
check cluster join API version
Request addition of this node
Join request OK, finishing setup locally
stopping pve-cluster service
backup old database to '/var/lib/pve-cluster/backup/config-1761243704.sql.gz'Step 4: Verify the Join Operation
After the join command, check cluster status:
As you can see above, this cluster is also using a QDevice, which in this case isn’t strictly necessary since the cluster already has three nodes. However, it has been added for testing and quorum behavior validation.
While a QDevice is typically recommended for two-node clusters to maintain quorum during network partitions, it can also be used in a three-node test environment to simulate failover scenarios and evaluate cluster resilience.
Best Practices for Cluster Network Design
Use Two Cluster Networks
ring0: Primary (e.g., 192.168.122.0/24)
ring1: Secondary (e.g., 192.168.123.0/24)
This provides redundancy and prevents quorum loss during link failure.
Keep Management and Cluster Traffic Separate
Isolate storage, management, and Corosync communication on different subnets or VLANs.Synchronize Hostnames
Ensure/etc/hostsand DNS are consistent across all nodes.Match Interface Names Across Nodes
Use predictable network interface names or rename NICs to match cluster configuration.
Conclusion
The error message
“pve1 has ring1_addr, but there is no interface number 1 configured”
is not a bug—it’s a network configuration mismatch during cluster expansion.
By aligning Corosync configuration, ensuring both cluster rings exist, or simplifying the network setup, you can successfully add new nodes to your Proxmox VE 9 cluster without disruption.