Every virtual machine (VM) gets an address in the main cluster network. The sections below cover how to view the assigned address, request a specific one, and keep it in the project.

IP addresses of VMs

Two resources describe the address of a machine in the main cluster network, the cluster-wide address lease and the address reserved for the project.

The .spec.settings.virtualMachineCIDRs block in the module settings defines the subnets that machines get IP addresses from. All addresses of a subnet are available except the first and the last one.

If an address pool is configured for the main cluster network in the sdn module, the address of a machine in that network is managed by the shared IPAM of that module, that is, by the same IPAddress resource as for additional networks. The address is requested automatically, and existing machines switch to the shared IPAM without changing their addresses and without a restart.

In a cluster with the shared IPAM, the VirtualMachineIPAddress and VirtualMachineIPAddressLease resources, as well as the .spec.virtualMachineIPAddressName parameter, are deprecated. They keep working and are described in the sections below, but the main network address of new machines is managed by the shared IPAM, covered in IPAM for the main network.

The cluster-wide VirtualMachineIPAddressLease (vmipl) resource manages leases of IP addresses from the shared pool specified in virtualMachineCIDRs, while the project VirtualMachineIPAddress (vmip) resource reserves leased addresses and binds them to machines. An address is assigned to a machine when the resource moves to the Attached phase. The other phases are described in the .status.phase field.

By default, Deckhouse Platform (DP) assigns an address to the machine itself and keeps it assigned until the machine is deleted. This works as follows:

  • You create a virtual machine named <VM_NAME>.
  • DP creates a VirtualMachineIPAddress resource named <VM_NAME>-<HASH> to request an IP address and bind it to the virtual machine.
  • For that resource, a VirtualMachineIPAddressLease lease is created, which picks a random IP address from the shared pool.
  • As soon as the VirtualMachineIPAddress resource is created, the virtual machine gets the assigned IP address.

After the machine is deleted, the VirtualMachineIPAddress resource is deleted too, but the address itself stays assigned to the project for a while, and you can request it again.

  • Using the CLI
  • Using the web interface

To view the list of IP address leases (vmipl), run the following command:

d8 k get vmipl

Example output:

NAME             VIRTUALMACHINEIPADDRESS                             STATUS   AGE
ip-10-66-10-14   {"name":"linux-vm-7prpx","namespace":"default"}     Bound    12h

To view the address assigned to a machine, run the following command:

d8 k get vmip

Example output:

NAME             ADDRESS       STATUS     VM         AGE
linux-vm-7prpx   10.66.10.14   Attached   linux-vm   12h
  1. Go to the Projects tab and select the project you need.
  2. Go to Virtualization → IP addresses.
  3. The list shows the resource name, status, address, type (Auto or Static), the virtual machine that uses the address, and the resource age.

Assigning a specific IP address

Instead of a random address from the pool, you can give a machine an address you choose in advance.

  • Using the CLI
  • Using the web interface

  1. Create a VirtualMachineIPAddress resource:

    d8 k apply -f - <<EOF
apiVersion: virtualization.deckhouse.io/v1alpha2
kind: VirtualMachineIPAddress
metadata:
  name: linux-vm-custom-ip
spec:
  staticIP: 10.66.20.77
  type: Static
EOF

  2. Create a new virtual machine or modify an existing one, and specify the VirtualMachineIPAddress resource you need explicitly in the specification:

    spec:
  virtualMachineIPAddressName: linux-vm-custom-ip
  1. Go to the Projects tab and select the project you need.
  2. Go to Virtualization → IP addresses.
  3. Click Create.
  4. In the Create resource window that opens, enter the resource name in the Name field.
  5. On the Configuration tab, select Static in the Type field, and specify the address you need in the Static IP address field.
  6. Click Apply.
  7. Specify the name of the created resource in the .spec.virtualMachineIPAddressName parameter of the virtual machine.

Keeping an IP address in the project

To keep the automatically allocated IP address of a virtual machine from being deleted along with the virtual machine itself, do the following.

Get the name of the VirtualMachineIPAddress resource for the given virtual machine:

d8 k get vm linux-vm -o jsonpath="{.status.virtualMachineIPAddressName}"

Example output:

linux-vm-7prpx

Remove the .metadata.ownerReferences block from the resource you found:

d8 k patch vmip linux-vm-7prpx --type=merge --patch '{"metadata":{"ownerReferences":null}}'

# Or make the same changes by editing the resource.

d8 k edit vmip linux-vm-7prpx

After the virtual machine is deleted, the VirtualMachineIPAddress resource is preserved and you can reuse it in a newly created virtual machine:

spec:
  virtualMachineIPAddressName: linux-vm-7prpx

Even if the VirtualMachineIPAddress resource is deleted, the IP address stays leased to the current project or namespace for another 10 minutes. So you can claim it again on request:

d8 k apply -f - <<EOF
apiVersion: virtualization.deckhouse.io/v1alpha2
kind: VirtualMachineIPAddress
metadata:
  name: linux-vm-custom-ip
spec:
  staticIP: 10.66.20.77
  type: Static
EOF

IPAM for the main network

The shared IPAM works only if an address pool is configured for the main cluster network in the sdn module. Without it, machine addresses are managed by the deprecated VirtualMachineIPAddress resources described above.

The address of a machine in the main network is held by the IPAddress resource of the sdn module, the same one that addresses additional networks. There are two ways to get an address:

  • Automatic: If the ipAddressName field isn’t set for the Main network, the controller creates an IPAddress resource bound to the machine and waits for the address before starting it. A machine that failed to get an address stays in the Pending phase, and the reason is shown by the VirtualMachineIPAddressReady condition.

  • Static: Create an IPAddress resource of the main network yourself and specify it in the .spec.networks[] parameter. Such a resource belongs to you, so it isn’t deleted along with the machine and can be reassigned to another one.

An example of a static IPAddress resource for the main network:

d8 k apply -f - <<EOF
apiVersion: network.deckhouse.io/v1alpha1
kind: IPAddress
metadata:
  name: linux-vm-main-ip
spec:
  networkRef:
    kind: ClusterNetwork
    name: main
  type: Static
  static:
    ip: 10.66.20.77
EOF

An example of a reference to this resource in the machine specification:

spec:
  networks:
    - type: Main
      ipAddressName: linux-vm-main-ip

Changing the ipAddressName field of the main network changes the address of the primary interface, so it requires a restart of the machine.

The current address and the name of the IPAddress resource it is assigned to are shown in the machine status:

d8 k get vm linux-vm -o jsonpath='{.status.networks[?(@.type=="Main")]}'

Example output:

{"id":1,"ipAddress":"10.66.10.14","ipAddressName":"linux-vm-4bkqr","type":"Main"}

Switching a machine to the shared IPAM

Machines that don’t reference a VirtualMachineIPAddress resource explicitly switch to the shared IPAM automatically, and the address doesn’t change and the machine isn’t restarted.

A machine with the .spec.virtualMachineIPAddressName parameter set keeps working through the deprecated mechanism, because the reference to the resource is set in its specification explicitly.

For the VirtualMachineIPAddress resource listed in the machine specification, DP maintains an IPAddress resource with the same name and the same address. To switch the machine and keep its address, replace one parameter with the other:

spec:
  # Remove the virtualMachineIPAddressName parameter.
  networks:
    - type: Main
      # An IPAddress resource with the same name and address.
      ipAddressName: linux-vm-custom-ip

Restart the machine to apply the change. The address stays the same, and the VirtualMachineIPAddress resource can be deleted after that.

Don’t remove the .spec.virtualMachineIPAddressName parameter without such a replacement, otherwise the machine gets a new address from the pool.

Additional resources