Networking Resources

This guide describes the core networking resources in IronCore, such as Networks, NetworkInterfaces, VirtualIPs, NAT gateways, LoadBalancers, and NetworkPolicies.

Network

A Network resource in IronCore refers to a logically isolated network (Layer 3). This further allows you to fully control your networking environment, including resource placement, connectivity, peering and security.

Example Network Resource

An example of how to define a Network resource in IronCore:

apiVersion: networking.ironcore.dev/v1alpha1
kind: Network
metadata:
  name: network-sample
spec:
  peerings:
  - name: peering1
    networkRef:
      name: network-sample2

Key Fields:

• peerings (list): Are the list of network peerings with this Network (optional).

More about IronCore Network:

• Network creation: ironcore-net is the network plugin for IronCore that realizes the Network resource. When an IronCore Network is created, a corresponding core.apinet.ironcore.dev/Network is created in the ironcore-net(apinet) cluster. Once created and with an allocated ID, the IronCore Network will be patched with the corresponding providerID of the apinet Network and set to state: Available. The format of a network providerID is as follows: ironcore-net://<namespace>/<name>/<id>/<uid>

• Network peering process: Network peering is a technique used to interleave two isolated networks, allowing members of both networks to communicate with each other as if they were in the same networking domain.

  • Information related to the referenced Network to be paired with is retrieved from the peering part of the spec.
  • Validation is done to see if both Networks have specified a matching peering item (i.e. reference each other via networkRef) to mutually accept the peering.
  • The binding phase of a spec.peerings item is reflected in a corresponding status.peerings item with the same name. The phase can either be Pending, meaning there is no active peering or Bound meaning the peering as described in the spec.peerings item is in place.

After successful reconciliation, the Ironcore Network resource gets updated with providerID, incomingpeerings and status.

apiVersion: networking.ironcore.dev/v1alpha1
kind: Network
metadata:
  name: network-sample
spec:
  peerings:
    - name: peering1
      networkRef:
      - name: network-sample2
  incomingPeerings:
    - name: network-sample2
  providerID: ironcore-net://ironcore-net-system/15e43205-3cfe-4b27-a29c-4ade42b94fca/11621310/292f19b4-2ff4-41e8-b324-075550340786
status:
  peerings:
  - name: peering1
    state: Ready
  state: Available

For detailed e2e example on network peering

• e2e example networkpeering

NetworkInterface

A NetworkInterface resource in IronCore represents a connection point between a Machine and a virtual network. It encapsulates the configuration and life cycle management of the virtual network interface, ensuring seamless connectivity for Machines.

Example NetworkInterface Resource

An example of how to define a NetworkInterface resource in IronCore:

apiVersion: networking.ironcore.dev/v1alpha1
kind: NetworkInterface
metadata:
  name: networkinterface-sample
spec:
  networkRef:
    name: network-sample
  ipFamilies:
    - IPv4
  ips:
    - value: 10.0.0.1 # internal IP
  virtualIP:
    virtualIPRef:
      name: virtualip-sample

Key Fields

• networkRef (string): NetworkRef is the Network this NetworkInterface is connected to.
• ipFamilies (list): IPFamilies defines the list of IPFamilies this NetworkInterface supports. Supported values for IPFamily are IPv4 and IPv6.
• ips (list): IPs are the list of provided internal IPs which should be assigned to this NetworkInterface
• virtualIP: VirtualIP specifies the public ip that should be assigned to this NetworkInterface.

After successful reconciliation of all NetworkInterfaces, the status gets updated with the corresponding values for ips, state, and virtualIP, as shown below.

status:
  ips:
  - 10.0.0.1
  lastStateTransitionTime: "2025-01-13T11:39:17Z"
  state: Available
  virtualIP: 172.89.244.23

VirtualIP

A VirtualIP (VIP) in the IronCore API is an abstract Network resource representing an IP address that is allocated and kept during the lifetime of the VirtualIP resource. It can be associated with a NetworkInterface of a Machine exposing this Machine e.g. to the public internet.

Example VirtualIP Resource

An example of how to define a VirtualIP resource in IronCore:

apiVersion: networking.ironcore.dev/v1alpha1
kind: VirtualIP
metadata:
  name: virtualip-sample
spec:
  type: Public
  ipFamily: IPv4

Key Fields

• type (string): Currently supported type is Public, which allocates and routes a stable public IP.
• ipFamily (string): IPFamily is the IP family of the VirtualIP. Supported values for IPFamily are IPv4 and IPv6.

After successful reconciliation of the VirtualIP resource, the status gets updated with the corresponding public IP address.

for example:

status:
  ip: 10.0.0.1 # This will be populated by the corresponding controller.

• Networking Configuration:
  • Machine Integration: The allocated VirtualIP is associated with the Machine in the VirtualIP part of the NetworkInterface spec.
  • Load Balancer Integration: If a load balancer is used, the VirtualIP is configured as the frontend IP to route requests to the Machine.

NATGateway

In the IronCore API, a NATGateway (Network Address Translation Gateway) facilitates outbound internet connectivity in private subnets, ensuring that instances in private subnets can access external services without exposing them to unauthorized inbound traffic.

Example NATGateway Resource

An example of how to define a NATGateway resource in IronCore:

apiVersion: networking.ironcore.dev/v1alpha1
kind: NATGateway
metadata:
  namespace: default
  name: natgateway-sample
spec:
  type: Public
  ipFamily: IPv4
  portsPerNetworkInterface: 64
  networkRef:
    name: network-sample

Key Fields

• type (string): This represents a NATGateway type that allocates and routes a stable public IP. The supported value for type is public
• ipFamily (string): IPFamily is the IP family of the NATGateway. Supported values for IPFamily are IPv4 and IPv6.
• portsPerNetworkInterface (int32): This Specifies the number of ports allocated per network interface and controls how many simultaneous connections can be handled per interface. If empty, 2048 (DefaultPortsPerNetworkInterface) is the default.
• networkRef (string): It represents which network this NATGateway serves.

After reconciling all NATGateways, the status gets updated with the corresponding values for ips as shown below.

status:
  ips:
  - name: ip1
    ip: 10.0.0.1

LoadBalancer

A LoadBalancer resource is an L3 (IP-based) load balancer service implementation provided by IronCore. It provides an externally accessible IP address that sends traffic to the correct port on your cluster nodes. IronCore LoadBalancer allows targeting multiple NetworkInterfaces and distributes traffic among them. This LoadBalancer supports single stack (IPv4 or IPv6) or dual stack IP addresses (IPv4/IPv6).

Example LoadBalancer Resource

An example of how to define a LoadBalancer resource in IronCore:

apiVersion: networking.ironcore.dev/v1alpha1
kind: LoadBalancer
metadata:
  namespace: default
  name: loadbalancer-sample
spec:
  type: Public
  ipFamilies: [IPv4]
  networkRef:
    name: network-sample
  networkInterfaceSelector:
    matchLabels:
      app: web
  ports:
  - port: 80

Key Fields:

• type (string): The type of LoadBalancer. Currently, two types of Loadbalancer are supported:
  • Public: LoadBalancer that allocates public IP and routes a stable public IP.
  • Internal: LoadBalancer that allocates and routes network-internal, stable IPs.
• ipFamilies (list): ipFamilies are the IP families the LoadBalancer should have(Supported values are IPv4 and IPv6).
• ips (list): The ips are the list of IPs to use. This can only be used when the type is LoadBalancerTypeInternal.
• networkRef (string): networkRef is the Network this LoadBalancer should belong to.
• networkInterfaceSelector (labelSelector): networkInterfaceSelector defines the NetworkInterfaces for which this LoadBalancer should be applied.
• ports (list): ports are the list of LoadBalancer ports should allow
  • protocol (string): protocol is the protocol the load balancer should allow. Supported protocols are UDP, TCP, and SCTP, if not specified defaults to TCP.
  • port (int): port is the port to allow.
  • endPort (int): endPort marks the end of the port range to allow. If unspecified, only a single port port will be allowed.

Sample LoadBalancerRouting object which is an internal type and is created by the LoadBalancerController:

apiVersion: networking.ironcore.dev/v1alpha1
kind: LoadBalancerRouting
metadata:
  namespace: default
  name: loadbalancer-sample # Same name as the load balancer it originates from.
# networkRef references the exact network object the routing belongs to.
networkRef:
  name: network-sample
# destinations list the target network interface instances (including UID) for load balancing.
destinations:
  - name: my-machine-interface-1
    uid: 2020dcf9-e030-427e-b0fc-4fec2016e73a
  - name: my-machine-interface-2
    uid: 2020dcf9-e030-427e-b0fc-4fec2016e73d

The LoadBalancerController in ironcore-net takes care of allocating IPs for defined ipFamilies in the spec and updates them in its status.ips.

For a detailed e2e example on LoadBalancer

• e2e example LoadBalancer

NetworkPolicy

In IronCore, NetworkPolicies are implemented based on the standard Kubernetes NetworkPolicy approach, which is enforced by the underlying IronCore's network plugin ironcore-net and other components. These policies use label selectors to define the source and destination of allowed traffic within the same network and can specify rules for both ingress (incoming) and egress (outgoing) traffic.

In IronCore, the NetworkPolicy has the following characteristics:

• NetworkPolicy is applied exclusively to NetworkInterfaces selected using label selectors.
• These NetworkInterfaces must belong to the same network.
• The policy governs traffic to and from other NetworkInterfaces, LoadBalancers, etc., based on the rules defined in the NetworkPolicy.

Example NetworkPolicy Resource

An example of how to define a NetworkPolicy resource in IronCore:

apiVersion: networking.ironcore.dev/v1alpha1
kind: NetworkPolicy
metadata:
  namespace: default
  name: my-network-policy
spec:
  networkRef:
    name: my-network
  networkInterfaceSelector:
    matchLabels:
      app: db
  policyTypes:
  - Ingress
  - Egress
  ingress:
  - from:
    - ipBlock:
        cidr: 172.17.0.0/16
    - objectSelector:
        kind: NetworkInterface
        matchLabels:
          app: web
    - objectSelector:
        kind: LoadBalancer
        matchLabels:
          app: web
    # Ports always have to be specified. Only traffic matching the ports
    # will be allowed.
    ports:
    - protocol: TCP
      port: 5432
  egress:
  - to:
    - ipBlock:
        cidr: 10.0.0.0/24
    ports:
    - protocol: TCP
      port: 8080

Key Fields

• networkRef (string): NetworkRef is the Network to regulate using this NetworkPolicy.

• networkInterfaceSelector (labelSelector): NetworkInterfaceSelector defines the target NetworkInterfaces for which this NetworkPolicy should be applied.

• policyTypes (list): There are two supported policyTypes Ingress and Egress.

• ingress (list): An Ingress section in a NetworkPolicy defines a list of NetworkPolicyIngressRules that specify which incoming traffic is allowed. Each NetworkPolicy can have multiple ingress rules, and each rule allows traffic that satisfies both the from and ports criteria.

  For example, a NetworkPolicy with a single ingress rule may permit traffic on a specific port and only from one of the following sources:

  • An IP range, defined using an ipBlock.
  • A set of resources identified by an objectSelector.

• egress (list): egress defines the list of NetworkPolicyEgressRules. Each NetworkPolicy may include a list of allowed egress rules. Each rule allows traffic that matches both to and ports sections. The example policy contains a single rule, which matches traffic on a single port to any destination in 10.0.0.0/24.

The IronCore project is responsible for managing the lifecycle of NetworkPolicy resources. Its primary function is to ensure that the rules specified by the user in the NetworkPolicy resource are enforced and applied on the target NetworkInterface.

For more detailed e2e example on NetworkPolicy

• e2e example on NetworkPolicy