Multus CNI สำหรับมือใหม่ Step by Step

Multus CNI

Multus CNI Meta Plugin Kubernetes Multi-homed Pod Network Interface SR-IOV MACVLAN IPVLAN NetworkAttachmentDefinition Telco 5G NFV Storage Management Production

Installation

# === Multus CNI Installation ===

# Install Multus (thick plugin)
# kubectl apply -f https://raw.githubusercontent.com/k8snetworkplumbingwg/multus-cni/master/deployments/multus-daemonset-thick.yml

# Verify installation
# kubectl get pods -n kube-system | grep multus
# kubectl get crd | grep network-attachment

# Helm Installation
# helm repo add rke2-charts https://rke2-charts.rancher.io
# helm install multus rke2-charts/rke2-multus -n kube-system

# NetworkAttachmentDefinition — Macvlan
# apiVersion: k8s.cni.cncf.io/v1
# kind: NetworkAttachmentDefinition
# metadata:
#   name: storage-net
#   namespace: default
# spec:
#   config: '{
#     "cniVersion": "0.3.1",
#     "type": "macvlan",
#     "master": "eth1",
#     "mode": "bridge",
#     "ipam": {
#       "type": "host-local",
#       "subnet": "192.168.100.0/24",
#       "rangeStart": "192.168.100.100",
#       "rangeEnd": "192.168.100.200",
#       "gateway": "192.168.100.1"
#     }
#   }'

# NetworkAttachmentDefinition — SR-IOV
# apiVersion: k8s.cni.cncf.io/v1
# kind: NetworkAttachmentDefinition
# metadata:
#   name: sriov-net
# spec:
#   config: '{
#     "cniVersion": "0.3.1",
#     "type": "sriov",
#     "vlan": 100,
#     "ipam": {
#       "type": "host-local",
#       "subnet": "10.10.100.0/24"
#     }
#   }'

# Pod with multiple networks
# apiVersion: v1
# kind: Pod
# metadata:
#   name: multi-net-pod
#   annotations:
#     k8s.v1.cni.cncf.io/networks: storage-net, sriov-net
# spec:
#   containers:
#     - name: app
#       image: nginx
#       # eth0 = default CNI
#       # net1 = storage-net (macvlan)
#       # net2 = sriov-net (sriov)

from dataclasses import dataclass

@dataclass
class NetworkConfig:
    name: str
    cni_type: str
    subnet: str
    interface: str
    vlan: str
    purpose: str

networks = [
    NetworkConfig("cluster-net", "Calico (default)", "10.244.0.0/16", "eth0", "N/A", "Pod-to-Pod default"),
    NetworkConfig("storage-net", "Macvlan", "192.168.100.0/24", "net1", "100", "Ceph storage traffic"),
    NetworkConfig("mgmt-net", "Macvlan", "192.168.200.0/24", "net2", "200", "SSH monitoring"),
    NetworkConfig("data-net", "SR-IOV", "10.10.100.0/24", "net3", "300", "High-speed data plane"),
]

print("=== Network Configurations ===")
for n in networks:
    print(f"  [{n.name}] Type: {n.cni_type}")
    print(f"    Subnet: {n.subnet} | IF: {n.interface} | VLAN: {n.vlan}")
    print(f"    Purpose: {n.purpose}")

Multi-homed Pod Design

# === Multi-homed Pod Examples ===

# Verify Pod networks
# kubectl exec multi-net-pod -- ip addr show
# kubectl exec multi-net-pod -- ip route
# kubectl get pods multi-net-pod -o jsonpath='{.metadata.annotations.k8s\.v1\.cni\.cncf\.io/network-status}'

# Deployment with Multus
# apiVersion: apps/v1
# kind: Deployment
# metadata:
#   name: storage-app
# spec:
#   replicas: 3
#   template:
#     metadata:
#       annotations:
#         k8s.v1.cni.cncf.io/networks: |
#           [
#             {"name": "storage-net", "interface": "net1"},
#             {"name": "mgmt-net", "interface": "net2", "ips": ["192.168.200.50"]}
#           ]
#     spec:
#       containers:
#         - name: app
#           image: my-storage-app:latest

@dataclass
class PodNetwork:
    pod: str
    default_ip: str
    additional: str
    total_interfaces: int
    use_case: str

pods = [
    PodNetwork("web-server", "10.244.1.10", "N/A (default only)", 1, "Standard web service"),
    PodNetwork("ceph-osd", "10.244.1.20", "storage-net: 192.168.100.20", 2, "Storage + cluster"),
    PodNetwork("db-replica", "10.244.1.30", "storage-net: 192.168.100.30, mgmt-net: 192.168.200.30", 3, "DB replication + mgmt"),
    PodNetwork("5g-upf", "10.244.1.40", "data-net: 10.10.100.40, mgmt-net: 192.168.200.40", 3, "Telco user plane"),
]

print("\n=== Multi-homed Pods ===")
for p in pods:
    print(f"  [{p.pod}] Default: {p.default_ip} | Interfaces: {p.total_interfaces}")
    print(f"    Additional: {p.additional}")
    print(f"    Use Case: {p.use_case}")

Troubleshooting

# === Multus Troubleshooting ===

# Check Multus DaemonSet
# kubectl get ds -n kube-system | grep multus
# kubectl logs -n kube-system ds/kube-multus-ds

# Check NAD
# kubectl get net-attach-def
# kubectl describe net-attach-def storage-net

# Common Issues
# 1. Pod stuck in ContainerCreating
#    → Check Multus logs: kubectl logs -n kube-system -l app=multus
#    → Verify NAD config JSON is valid
#
# 2. No IP assigned on additional interface
#    → Check IPAM config: subnet range exhausted?
#    → Verify master interface exists on node
#
# 3. Cannot reach other pods on additional network
#    → Check VLAN tagging on physical switch
#    → Verify ARP/routing on macvlan bridge mode

@dataclass
class TroubleshootItem:
    issue: str
    symptom: str
    check_command: str
    fix: str

issues = [
    TroubleshootItem("Pod ContainerCreating", "Pod ค้าง ไม่ Running",
        "kubectl describe pod; kubectl logs -n kube-system multus",
        "ตรวจ NAD JSON valid, master interface exists"),
    TroubleshootItem("No IP on net1", "ip addr show net1 ไม่มี IP",
        "kubectl exec pod -- ip addr; check IPAM range",
        "เพิ่ม IP Range หรือตรวจ Subnet Config"),
    TroubleshootItem("Cannot ping across net", "Pod คุยกันไม่ได้บน net เพิ่ม",
        "kubectl exec pod -- ping 192.168.100.x",
        "ตรวจ VLAN Switch, macvlan mode, routing"),
    TroubleshootItem("NAD not found", "net-attach-def not found",
        "kubectl get net-attach-def -n NAMESPACE",
        "สร้าง NAD ใน Namespace เดียวกับ Pod"),
    TroubleshootItem("Performance low", "Throughput ต่ำกว่าที่คาด",
        "iperf3 between pods on additional net",
        "ใช้ SR-IOV แทน macvlan, ตรวจ NIC offload"),
]

print("Troubleshooting Guide:")
for t in issues:
    print(f"  [{t.issue}] {t.symptom}")
    print(f"    Check: {t.check_command}")
    print(f"    Fix: {t.fix}")

เคล็ดลับ

• Default CNI: ติดตั้ง Default CNI ก่อน Multus เสมอ
• Macvlan: เริ่มจาก Macvlan ง่ายที่สุดสำหรับมือใหม่
• SR-IOV: ใช้ SR-IOV สำหรับ High Performance ต้องมี NIC รองรับ
• VLAN: ตั้ง VLAN บน Physical Switch ให้ตรงกับ NAD Config
• Test: ใช้ iperf3 ทดสอบ Bandwidth ระหว่าง Pod บน Additional Network

Multus CNI คืออะไร

Meta CNI Plugin Kubernetes หลาย Network Interface Pod SR-IOV MACVLAN IPVLAN Bridge NFV Telco 5G Storage Management Data Control Plane

สรุป

Multus CNI Meta Plugin Kubernetes Multi-homed Pod NetworkAttachmentDefinition Macvlan SR-IOV IPVLAN Bridge Telco 5G Storage Management Production Network Design