What is Kubernetes IPVS mode?

Question

Accepted Answer

**IPVS** — high-performance load balancing for Services.

```bash
# Check kube-proxy mode
kubectl get configmap kube-proxy -n kube-system -o yaml | grep mode

# Switch to IPVS
kubectl edit configmap kube-proxy -n kube-system
# Set: mode: "ipvs"

# Restart kube-proxy
kubectl rollout restart daemonset kube-proxy -n kube-system

# Verify IPVS rules
ipvsadm -Ln
ipvsadm -Ln -t 10.96.0.10:53  # DNS service
ipvsadm -Ln --stats  # Statistics

# Check IPVS scheduler
ipvsadm -Ln | grep -i "sched"

# Debug IPVS
ipvsadm -Ln --rate  # Connection rates
conntrack -L  # Connection tracking
```

```yaml
# kube-proxy ConfigMap
apiVersion: v1
kind: ConfigMap
metadata:
  name: kube-proxy
  namespace: kube-system
data:
  config.conf: |
    mode: "ipvs"
    ipvs:
      scheduler: "rr"  # Round Robin
      strictARP: false
      syncPeriod: "30s"
      minSyncPeriod: "2s"
    iptables:
      masqueradeAll: false
      masqueradeBit: 14
```

**IPVS Scheduling Algorithms:**
- rr: Round Robin.
- lc: Least Connections.
- dh: Destination Hashing.
- sh: Source Hashing.
- sed: Shortest Expected Delay.
- nq: Never Queue.

**Benefits over iptables:**
- O(1) lookup vs O(n).
- More load balancing algorithms.
- Better performance at scale.

DevOps: What is Kubernetes IPVS mode?