kvm instance network sometimes fail when use bridge, how to fix this?

xiedeacc

10/10/23, 11:17 AM

my host and guests OS all are ubuntu server 22.04. bridge created by host use below netplan config, host and guest can reach each other. but when I use kubeadm init to init a k8s cluster, http request to guest itself sametimes timeout, so whole init will fail. how to fix this problem?

➜  /root cat /etc/netplan/01-netcfg.yaml
network:
  version: 2
  ethernets:
    enp5s0:
      dhcp4: false
      dhcp6: false
  bridges:
    br0:
      interfaces: [enp5s0]
      dhcp4: false
      dhcp6: false
      addresses: [192.168.101.20/24]
      routes:
        - to: default
          via: 192.168.101.1
          metric: 100
      nameservers:
        addresses: [192.168.101.1]
      mtu: 1500

I also enable below parameters for br_netfilter

vi /etc/sysctl.d/99-netfilter-bridge.conf
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1

some kubeadm log, we can see some request responsed well, but some timedout

I1010 10:17:41.644715    7039 round_trippers.go:473]     Accept: application/json, */*
I1010 10:17:41.736712    7039 round_trippers.go:574] Response Status: 422 Unprocessable Entity in 91 milliseconds
I1010 10:17:41.737253    7039 round_trippers.go:463] PUT https://192.168.101.24:6443/api/v1/namespaces/kube-system/services/kube-dns?timeout=10s
I1010 10:17:41.737267    7039 round_trippers.go:469] Request Headers:
I1010 10:17:41.737275    7039 round_trippers.go:473]     Accept: application/json, */*
I1010 10:17:41.737282    7039 round_trippers.go:473]     Content-Type: application/json
I1010 10:17:41.737288    7039 round_trippers.go:473]     User-Agent: kubeadm/v1.25.2 (linux/amd64) kubernetes/5835544
I1010 10:17:51.738173    7039 round_trippers.go:574] Response Status:  in 10000 milliseconds
Put "https://192.168.101.24:6443/api/v1/namespaces/kube-system/services/kube-dns?timeout=10s": net/http: request canceled (Client.Timeout exceeded while awaiting headers)
unable to create/update the DNS service
k8s.io/kubernetes/cmd/kubeadm/app/phases/addons/dns.createDNSService
        cmd/kubeadm/app/phases/addons/dns/dns.go:275
k8s.io/kubernetes/cmd/kubeadm/app/phases/addons/dns.createCoreDNSAddon

237

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networking

ubuntu

timeout

kvm-virtualization

c4f4t0r

10/10/23, 11:30 AM

check if you have any iptables rules on the host.

xiedeacc

10/10/23, 2:26 PM

no any iptables rules

xiedeacc

10/10/23, 2:27 PM

kubeadm init success on physical machine

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