VMmanager 6: Administrator guide

Assigning IP addresses to cluster nodes

In VMmanager, there are two types of assigning IP addresses to cluster nodes: "To cluster" and "To node". Assigning type "To node" is used, for example, in Hetzner and OVH data centers.

Assigning type "To cluster"


A pool is allocated for the cluster, combining blocks of IP addresses from physical networks. You can manage IP addresses of this pool in the Networks section. Migration of virtual machines (VMs) between cluster nodes is available for this type of IP address assigning.

Example of network settings

A pool of IP addresses 192.168.10.0/24 is allocated for the cluster. VMmanager assigns addresses from this pool for VMs on cluster nodes.

Assigning type "To node"


A cluster node in a data center is assigned the primary IP address and a subnet of additional IP addresses. Virtual machines on this node are allocated only the IP addresses from the specified subnet. When connecting a node to the cluster, a range of allowable IP addresses for the virtual machine is specified. The newly created virtual machine on the node is assigned the first available IP address from the range. You can manage IP addresses in the node dashboard: Nodes → node name → IP addresses.

VM routing is performed through the virtual interfaces vnet and the interface of the network bridge vmbr0. This subnet routing type does not allow migrating virtual machines to other cluster nodes.

The Port Security function is enabled on the data center equipment. This function prevents from sending Ethernet frames if the sender MAC-address is not specified as allowed. Since a KVM virtual machine has a separate MAC-address, frames from the virtual machine will be blocked on the network equipment. To avoid this, VMmanager modifies network settings on the node so that the MAC-address in the VM frames will be changed into the MAC-address of the cluster node network interface. 

Example of network settings

The server is assigned the primary IP address 123.45.12.48 and the subnet 203.0.113.40/29. As the subnet IP addresses will be used as additional, the virtual machine can be allocated all the addresses from this subnet: 203.0.113.40, 203.0.113.41, ..., 203.0.113.47. The primary IP address of the server on the network interface eno1 is used as the subnet gateway.

Operation scheme

How to configure IPv6 on cluster nodes in the Hetzner data center


To configure IPv6 routing, add IPv6 address to the cluster node: Nodes node name IP addresses IPv6  Add an IP address. For correct operation of IPv6 network, specify the address ::2 and prefix length 64. Example: 2a01:4f8:13b:9a7::2/64. VMmanager will configure the network in the node automatically.