Network Function operator

This page describes the specialized Network Function Kubernetes operator that Google Distributed Cloud connected ships with. This operator implements a set of CustomResourceDefinitions (CRDs) that allow Distributed Cloud connected to execute high-performance workloads.

The Network Function operator lets you do the following:

  • Poll for existing network devices on a node.
  • Query the IP address and physical link state for each network device on a node.
  • Provision additional network interfaces on a node.
  • Configure low-level system features on the node's physical machine required to support high-performance workloads.

Network Function operator profiles

Distributed Cloud connected provides the following Network Function operator functionality:

  • Network automation functions let you automate the configuration of your workload Pod networking.

  • State export functions let you export host network states to the user, including network interface configuration and status.

  • Webhook functions let you validate user inputs.

Prerequisites

The Network Function operator fetches network configuration from the Distributed Cloud Edge Network API. To allow this, you must grant the Network Function operator service account the Edge Network Viewer role (roles/edgenetwork.viewer) using the following command:

gcloud projects add-iam-policy-binding ZONE_PROJECT_ID \
  --role roles/edgenetwork.viewer \
  --member "serviceAccount:CLUSTER_PROJECT_ID.svc.id.goog[nf-operator/nf-angautomator-sa]"

Replace the following:

  • ZONE_PROJECT_ID with the ID of the Google Cloud project that holds the Distributed Cloud Edge Network API resources.
  • CLUSTER_PROJECT_ID with the ID of the Google Cloud project that holds the target Distributed Cloud connected cluster.

Network Function operator resources

The Distributed Cloud connected Network Function operator implements the following Kubernetes CRDs:

  • Network. Defines a virtual network that pods can use to communicate with internal and external resources. You must create the corresponding VLAN using the Distributed Cloud Edge Network API before specifying it in this resource. For instructions, see Create a subnetwork.
  • NetworkInterfaceState. Enables the discovery of network interface states and querying a network interface for link state and IP address.
  • NodeSystemConfigUpdate. Enables the configuration of low-level system features such as kernel options and Kubelet flags.
  • NetworkAttachmentDefinition. Lets you attach Distributed Cloud pods to one or more logical or physical networks on your Distributed Cloud connected node. You must create the corresponding VLAN using the Distributed Cloud Edge Network API before specifying it in this resource. For instructions, see Create a subnetwork.

The Network Function operator also lets you define secondary network interfaces.

Network resource

The Network resource defines a virtual network within your Distributed Cloud connected deployment that pods within your Distributed Cloud connected cluster can use to communicate with internal and external resources.

The Network resource provides the following configurable parameters for the network interface exposed as writable fields:

  • spec.type: specifies the network transport layer for this network. The only valid value is L2. You must also specify a nodeInterfaceMatcher.interfaceName value.
  • spec.nodeInterfaceMatcher.interfaceName: the name of the physical network interface on the target Distributed Cloud connected node to use with this network.
  • spec.gateway4: the IP address of the network gateway for this network.
  • spec.l2NetworkConfig.prefixLength4: specifies the CIDR range for this network.
  • annotations.networking.gke.io/gdce-per-node-ipam-size: specifies the subnet mask size for an individual node. If this is omitted, the subnet mask size is set to the value of the cluster-cidr-config-per-node-mask-size field in the nf-operator-defaults ConfigMap in the nf-operator namespace.
  • annotations.networking.gke.io/gke-gateway-clusterip-cidr: specifies a CIDR block for accessing clusters through Connect gateway. This is used by CoreDNS on secondary network interfaces.
  • annotations.networking.gke.io/gke-gateway-pod-cidr: specifies a CIDR block for a Pod that can be allocated on secondary network interfaces.
  • annotations.networking.gke.io/gdce-vlan-id: specifies the VLAN ID for this network.
  • annotations.networking.gke.io/gdce-vlan-mtu: (optional) specifies the MTU value for this network. If omitted, inherits the MTU value from the parent interface.
  • annotations.networking.gke.io/gdce-lb-service-vip-cidr: specifies the virtual IP address range for the load balancing service. The value can be a CIDR block or an explicit address range value. This annotation is mandatory for Layer 3 and optional for Layer 2 load balancing.

The following example illustrates the structure of the resource:

apiVersion: networking.gke.io/v1
kind: Network
metadata:
  name: vlan200-network
  annotations:
    networking.gke.io/gdce-vlan-id: 200
    networking.gke.io/gdce-vlan-mtu: 1500
    networking.gke.io/gdce-lb-service-vip-cidrs: "10.1.1.0/24"
spec:
  type: L2
  nodeInterfaceMatcher:
    interfaceName: gdcenet0.200
  gateway4: 10.53.0.1

To specify multiple virtual IP address ranges for the load balancing service, use the networking.gke.io/gdce-lb-service-vip-cidrs annotation. You can provide the values for this annotation as either a comma-separated list or as a JSON payload. For example:

[
  {
    "name": "test-oam-3",
    "addresses": ["10.235.128.133-10.235.128.133"],
    "autoAssign": false
  }
  ,
  {
    "name": "test-oam-4",
    "addresses": ["10.235.128.134-10.235.128.134"],
    "autoAssign": false
  },
  {
    "name": "test-oam-5",
    "addresses": ["10.235.128.135-10.235.128.135"],
    "autoAssign": false
  }
]

If you choose to use a JSON payload, we recommend that you use the condensed JSON format. For example:

apiVersion: networking.gke.io/v1
  kind: Network
  metadata:
    annotations:
      networking.gke.io/gdce-lb-service-vip-cidrs: '[{"name":"test-oam-3","addresses":["10.235.128.133-10.235.128.133"],"autoAssign":false},{"name":"test-oam-4","addresses":["10.235.128.134-10.235.128.134"],"autoAssign":false},{"name":"test-oam-5","addresses":["10.235.128.135-10.235.128.135"],"autoAssign":false}]'
      networking.gke.io/gdce-vlan-id: "81"
    name: test-network-vlan81
  spec:
    IPAMMode: Internal
    dnsConfig:
      nameservers:
      - 8.8.8.8
    gateway4: 192.168.81.1
    l2NetworkConfig:
      prefixLength4: 24
    nodeInterfaceMatcher:
      interfaceName: gdcenet0.81
    type: L2

Keep in mind that the autoAssign field defaults to false if omitted.

NetworkInterfaceState resource

The NetworkInterfaceState resource is a read-only resource that lets you discover physical network interfaces on the node and collect runtime statistics on the network traffic flowing through those interfaces. Distributed Cloud creates a NetworkInterfaceState resource for each node in a cluster.

The default configuration of Distributed Cloud connected machines includes a bonded network interface named uplink0. This interface bonds the eno1np0 and eno2np1 network interfaces. Each of those is connected to one Distributed Cloud ToR switch, respectively.

The NetworkInterfaceState resource provides the following categories of network interface information exposed as read-only status fields.

General information:

  • status.interfaces.ifname: the name of the target network interface.
  • status.lastReportTime: the time and date of the last status report for the target interface.

IP address configuration information:

  • status.interfaces.interfaceinfo.address: the IP address assigned to the target interface.
  • status.interfaces.interfaceinfo.dns: the IP address of the DNS server assigned to the target interface.
  • status.interfaces.interfaceinfo.gateway: the IP address of the network gateway serving the target interface.
  • status.interfaces.interfaceinfo.prefixlen: the length of the IP prefix.

Hardware information:

  • status.interfaces.linkinfo.broadcast: the broadcast MAC address of the target interface.
  • status.interfaces.linkinfo.businfo: the PCIe device path in bus:slot.function format.
  • status.interfaces.linkinfo.flags: the interface flags—for example, BROADCAST.
  • status.interfaces.linkinfo.macAddress: the Unicast MAC address of the target interface.
  • status.interfaces.linkinfo.mtu: the MTU value for the target interface.

Reception statistics:

  • status.interfaces.statistics.rx.bytes: the total bytes received by the target interface.
  • status.interfaces.statistics.rx.dropped: the total packets dropped by the target interface.
  • status.interfaces.statistics.rx.errors: the total packet receive errors for the target interface.
  • status.interfaces.statistics.rx.multicast: the total multicast packets received by the target interface.
  • status.interfaces.statistics.rx.overErrors: the total packet receive over errors for the target interface.
  • status.interfaces.statistics.rx.packets: the total packets received by the target interface.

Transmission statistics:

  • status.interfaces.statistics.tx.bytes: the total bytes transmitted by the target interface.
  • status.interfaces.statistics.tx.carrierErrors: the total carrier errors encountered by the target interface.
  • status.interfaces.statistics.tx.collisions: the total packet collisions encountered by the target interface.
  • status.interfaces.statistics.tx.dropped: the total packets dropped by the target interface.
  • status.interfaces.statistics.tx.errors: the total transmission errors for the target interface.
  • status.interfaces.statistics.tx.packets: the total packets transmitted by the target interface.

The following example illustrates the structure of the resource:

apiVersion: networking.gke.io/v1
kind: NetworkInterfaceState
metadata:
  name: MyNode1
nodeName: MyNode1
status:
  interfaces:
  - ifname: eno1np0
    linkinfo:
      businfo: 0000:1a:00.0
      flags: up|broadcast|multicast
      macAddress: ba:16:03:9e:9c:87
      mtu: 9000
    statistics:
      rx:
        bytes: 1098522811
        errors: 2
        multicast: 190926
        packets: 4988200
      tx:
        bytes: 62157709961
        packets: 169847139
  - ifname: eno2np1
    linkinfo:
      businfo: 0000:1a:00.1
      flags: up|broadcast|multicast
      macAddress: ba:16:03:9e:9c:87
      mtu: 9000
    statistics:
      rx:
        bytes: 33061895405
        multicast: 110203
        packets: 110447356
      tx:
        bytes: 2370516278
        packets: 11324730
  - ifname: enp95s0f0np0
    interfaceinfo:
    - address: fe80::63f:72ff:fec4:2bf4
      prefixlen: 64
    linkinfo:
      businfo: 0000:5f:00.0
      flags: up|broadcast|multicast
      macAddress: 04:3f:72:c4:2b:f4
      mtu: 9000
    statistics:
      rx:
        bytes: 37858381
        multicast: 205645
        packets: 205645
      tx:
        bytes: 1207334
        packets: 6542
  - ifname: enp95s0f1np1
    interfaceinfo:
    - address: fe80::63f:72ff:fec4:2bf5
      prefixlen: 64
    linkinfo:
      businfo: 0000:5f:00.1
      flags: up|broadcast|multicast
      macAddress: 04:3f:72:c4:2b:f5
      mtu: 9000
    statistics:
      rx:
        bytes: 37852406
        multicast: 205607
        packets: 205607
      tx:
        bytes: 1207872
        packets: 6545
  - ifname: enp134s0f0np0
    interfaceinfo:
    - address: fe80::63f:72ff:fec4:2b6c
      prefixlen: 64
    linkinfo:
      businfo: 0000:86:00.0
      flags: up|broadcast|multicast
      macAddress: 04:3f:72:c4:2b:6c
      mtu: 9000
    statistics:
      rx:
        bytes: 37988773
        multicast: 205584
        packets: 205584
      tx:
        bytes: 1212385
        packets: 6546
  - ifname: enp134s0f1np1
    interfaceinfo:
    - address: fe80::63f:72ff:fec4:2b6d
      prefixlen: 64
    linkinfo:
      businfo: 0000:86:00.1
      flags: up|broadcast|multicast
      macAddress: 04:3f:72:c4:2b:6d
      mtu: 9000
    statistics:
      rx:
        bytes: 37980702
        multicast: 205548
        packets: 205548
      tx:
        bytes: 1212297
        packets: 6548
  - ifname: gdcenet0
    interfaceinfo:
    - address: 208.117.254.36
      prefixlen: 28
    - address: fe80::b816:3ff:fe9e:9c87
      prefixlen: 64
    linkinfo:
      flags: up|broadcast|multicast
      macAddress: ba:16:03:9e:9c:87
      mtu: 9000
    statistics:
      rx:
        bytes: 34160422968
        errors: 2
        multicast: 301129
        packets: 115435591
      tx:
        bytes: 64528301111
        packets: 181171964
     .. <remaining interfaces omitted>
   lastReportTime: "2022-03-30T07:35:44Z"

NodeSystemConfigUpdate resource

The NodeSystemConfigUpdate resource lets you make changes to the node's operating system configuration as well as modify Kubelet flags. Changes other than sysctl changes require a node reboot. This resource is not available on Distributed Cloud connected servers deployments.

When instantiating this resource, you must specify the target nodes in the nodeSelector field. You must include all key-value pairs for each target node in the nodeSelector field. When you specify more than one target node in this field, the target nodes are updated one node at a time.

CAUTION: The nodeName field has been deprecated. Using it immediately reboots the target nodes, including local control plane nodes, which can halt critical workloads.

The NodeSystemConfigUpdate resource provides the following configuration fields specific to Distributed Cloud connected:

  • spec.containerRuntimeDNSConfig.ip: specifies a list of IP addresses for private image registries.

  • spec.containerRuntimeDNSConfig: specifies a list of custom DNS entries used by the Container Runtime Environment on each Distributed Cloud connected node. Each entry consists of the following fields:

    • ip: specifies the target IPv4 address,
    • domain: specifies the corresponding domain,
    • interface: specifies the network egress interface through which the IP address specified in the ip field is reachable. You can specify an interface defined through the following resources: CustomNetworkInterfaceConfig, Network (by annotation), NetworkAttachmentDefinition, (by annotation).

  • spec.kubeletConfig.cpuManagerPolicy: specifies the Kubernetes CPUManager policy. Valid values are None and Static.

  • spec.kubeletConfig.topologyManagerPolicy: specifies the Kubernetes TopologyManager policy. Valid values are None, BestEffort, Restricted, and SingleNumaMode.

  • spec.osConfig.cgroupConfig.noKernelMemory: excludes kernel-space memory from Pod memory usage calculation. Valid values are true and false.

  • spec.osConfig.hugePagesConfig: specifies the huge page configuration per NUMA node. Valid values are 2MB and 1GB. The number of huge pages requested is evenly distributed across both NUMA nodes in the system. For example, if you allocate 16 huge pages at 1 GB each, then each node receives a pre-allocation of 8 GB.

  • spec.osConfig.isolatedCpusPerSocket: specifies the number of isolated CPUs per socket. Required if cpuManagerPolicy is set to Static. The maximum number of isolated CPUs must be fewer than 80% of the total CPUs in the node.

  • spec.osConfig.cpuIsolationPolicy: specifies the CPU isolation policy. The Default policy only isolates systemd tasks from CPUs reserved for workloads. The Kernel policy marks the CPUs as isolcpus and sets the rcu_nocb, nohz_full, and rcu_nocb_poll flags on each CPU. The KernelOptimized policy marks the CPUs as isolcpus and sets the rcu_nocb and rcu_nocb_poll flags on each CPU, but not the nohz_full flag.

  • spec.sysctls.NodeLevel: specifies the sysctls parameters that you can configure globally on a node by using the Network Function operator. The configurable parameters are as follows:

    • fs.inotify.max_user_instances
    • fs.inotify.max_user_watches
    • kernel.sched_rt_runtime_us
    • kernel.core_pattern
    • net.ipv4.tcp_wmem
    • net.ipv4.tcp_rmem
    • net.ipv4.tcp_slow_start_after_idle
    • net.ipv4.udp_rmem_min
    • net.ipv4.udp_wmem_min
    • net.ipv4.tcp_rmem
    • net.ipv4.tcp_wmem
    • net.core.rmem_max
    • net.core.wmem_max
    • net.core.rmem_default
    • net.core.wmem_default
    • net.netfilter.nf_conntrack_tcp_timeout_unacknowledged
    • net.netfilter.nf_conntrack_tcp_timeout_max_retrans
    • net.sctp.auth_enable
    • net.sctp.sctp_mem
    • net.ipv4.udp_mem
    • net.ipv4.tcp_mem
    • net.ipv4.tcp_slow_start_after_idle
    • net.sctp.auth_enable
    • vm.max_map_count

    You can also scope both safe and unsafe sysctls parameters to a specific pod or namespace by using the tuning Container Networking Interface (CNI) plug-in.

The NodeSystemConfigUpdate resource provides the following read-only general status fields:

  • status.lastReportTime: the most recent time that status was reported for the target interface.
  • status.conditions.lastTransitionTime: the most recent time that the condition of the interface has changed.
  • status.conditions.observedGeneration: denotes the .metadata.generation value on which the initial condition was based.
  • status.conditions.message: an informative message describing the change of the interface's condition.
  • status.conditions.reason: a programmatic identifier denoting the reason for the last change of the interface's condition.
  • status.conditions.status: the status descriptor of the condition. Valid values are True, False, and Unknown.
  • status.conditions.type: the condition type in camelCase.

The following example illustrates the structure of the resource:

apiVersion: networking.gke.io/v1
kind: NodeSystemConfigUpdate
metadata:
  name: node-pool-1-config
  namespace: default
spec:
  nodeSelector:
    baremetal.cluster.gke.io/node-pool: node-pool-1
  sysctls:
    nodeLevel:
      "net.ipv4.udp_mem" : "12348035 16464042 24696060"
  kubeletConfig:
    topologyManagerPolicy: BestEffort
    cpuManagerPolicy: Static
  osConfig:
    hugePagesConfig:
      "TWO_MB": 0
      "ONE_GB": 16
    isolatedCpusPerSocket:
      "0": 10
      "1": 10

Configure a secondary interface on a pod using Distributed Cloud multi-networking

Distributed Cloud connected supports creating a secondary network interface on a pod by using its multi-network feature. To do so, complete the following steps:

  1. Configure a Network resource. For example:

    apiVersion: networking.gke.io/v1
kind: Network
metadata:
  name: my-network-410
  annotations:
      networking.gke.io/gdce-vlan-id: "410"
      networking.gke.io/gdce-lb-service-vip-cidrs: '[{"name":"myPool","addresses":["10.100.63.130-10.100.63.135"],"avoidBuggyIPs":false,"autoAssign":true}]'
spec:
  type: L2
  nodeInterfaceMatcher:
    interfaceName: gdcenet0.410
  gateway4: 10.100.63.129
  l2NetworkConfig:
    prefixLength4: 27

    The networking.gke.io/gdce-lb-service-vip-cidrs annotation specifies one or more IP address pools for this virtual network. The first half of the CIDR you specify here must include Service Virtual IP (SVIP) addresses. Distributed Cloud connected enforces this requirement through webhook checks as follows:

    • The SVIP address range must be within the corresponding VLAN CIDR range, and
    • The SVIP address range can only span up to the first half of the VLAN CIDR range.

  2. Add an annotation to your Distributed Cloud pod definition as follows:

    apiVersion: v1
kind: pod
metadata:
  name: myPod
  annotations:
    networking.gke.io/interfaces: '[{"interfaceName":"eth0","network":"pod-network"}, {"interfaceName":"eth1","network":"my-network-410"}]'
    networking.gke.io/default-interface: eth1

    This annotation configures the eth0 interface as primary and the eth1 interface as secondary with Layer2 load balancing with MetalLB.

Configuring your secondary interface as described in this section results in the automatic creation of the following custom resources:

  • An IPAddressPool resource, which enables automatic SVIP address assignment to Pods. For example:
apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  name: test-410-pool
  namespace: kube-system
  annotations:
    networking.gke.io/network:my-network-410
    …
  spec:
  addresses:
  - 10.100.63.130-10.100.63.135
  autoAssign: true
  • An L2Advertisement resource, which enables advertising of the specified SVIP addresses. For example:
apiVersion: metallb.io/v1beta1
kind: L2Advertisement
metadata:
  name: l2advertise-410
  namespace: kube-system
spec:
  ipAddressPools:
  - test-410-pool
  interfaces:
  - gdcenet0.410

## What's next