相关资料
kubernetes 网络插件列表：kubernetes.io/zh-cn/docs/…
flannel 网络插件：github.com/flannel-io/…
安装步骤
我们 kubeadm init 初始化好集群后，获取节点信息看一下，STATUS 值为 NotReady，是因为没有安装网络插件导致
root@server-01:~# kubectl get nodes
NAME STATUS ROLES AGE VERSION
server-01 NotReady control-plane 28m v1.34.1
可以提前使用 crictl 拉镜像备用，会快点，具体镜像参考文件 github.com/flannel-io/… 中的 image
root@server-03:~# crictl pull ghcr.io/flannel-io/flannel-cni-plugin:v1.8.0-flannel1
WARN[0000] Config "/etc/crictl.yaml" does not exist, trying next: "/usr/bin/crictl.yaml"
WARN[0000] Image connect using default endpoints: [unix:///run/containerd/containerd.sock unix:///run/crio/crio.sock unix:///var/run/cri-dockerd.sock]. As the default settings are now deprecated, you should set the endpoint instead.
Image is up to date for sha256:bb28ded63816ef094b17e6d91e875e41e239c6b1eedfbdbbf07048b799af63e0
root@server-03:~# crictl pull ghcr.io/flannel-io/flannel:v0.27.4
WARN[0000] Config "/etc/crictl.yaml" does not exist, trying next: "/usr/bin/crictl.yaml"
WARN[0000] Image connect using default endpoints: [unix:///run/containerd/containerd.sock unix:///run/crio/crio.sock unix:///var/run/cri-dockerd.sock]. As the default settings are now deprecated, you should set the endpoint instead.
Image is up to date for sha256:e83704a1773124a27dda6471ae26962cd6fac4fa8df3dac15034f8729a9ed3ab
安装插件
root@server-01:~# kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml
namespace/kube-flannel created
serviceaccount/flannel created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
报错
root@server-01:~# kubectl get pods -A
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-flannel kube-flannel-ds-njtqv 0/1 Error 2 (25s ago) 29s
kube-system coredns-66bc5c9577-kr6n7 0/1 ContainerCreating 0 50m
kube-system coredns-66bc5c9577-rhgnh 0/1 ContainerCreating 0 50m
kube-system etcd-server-01 1/1 Running 0 50m
kube-system kube-apiserver-server-01 1/1 Running 0 50m
kube-system kube-controller-manager-server-01 1/1 Running 0 50m
kube-system kube-proxy-fm9cz 1/1 Running 0 50m
kube-system kube-scheduler-server-01 1/1 Running 0 50m
root@server-01:~# kubectl logs -n kube-flannel kube-flannel-ds-njtqv
Defaulted container "kube-flannel" out of: kube-flannel, install-cni-plugin (init), install-cni (init)
I1030 09:36:50.334879 1 main.go:215] CLI flags config: {etcdEndpoints:http://127.0.0.1:4001,http://127.0.0.1:2379 etcdPrefix:/coreos.com/network etcdKeyfile: etcdCertfile: etcdCAFile: etcdUsername: etcdPassword: version:false kubeSubnetMgr:true kubeApiUrl: kubeAnnotationPrefix:flannel.alpha.coreos.com kubeConfigFile: iface:[] ifaceRegex:[] ipMasq:true ipMasqRandomFullyDisable:false ifaceCanReach: subnetFile:/run/flannel/subnet.env publicIP: publicIPv6: subnetLeaseRenewMargin:60 healthzIP:0.0.0.0 healthzPort:0 iptablesResyncSeconds:5 iptablesForwardRules:true blackholeRoute:false netConfPath:/etc/kube-flannel/net-conf.json setNodeNetworkUnavailable:true}
W1030 09:36:50.334999 1 client_config.go:659] Neither --kubeconfig nor --master was specified. Using the inClusterConfig. This might not work.
I1030 09:36:50.346561 1 kube.go:139] Waiting 10m0s for node controller to sync
I1030 09:36:50.346605 1 kube.go:537] Starting kube subnet manager
I1030 09:36:51.346887 1 kube.go:163] Node controller sync successful
I1030 09:36:51.346966 1 main.go:241] Created subnet manager: Kubernetes Subnet Manager - server-01
I1030 09:36:51.346972 1 main.go:244] Installing signal handlers
I1030 09:36:51.347653 1 main.go:523] Found network config - Backend type: vxlan
E1030 09:36:51.347807 1 main.go:278] Failed to check br_netfilter: stat /proc/sys/net/bridge/bridge-nf-call-iptables: no such file or director
br_netfilter 内核模块未加载，这是 Flannel 运行的必要条件。
# 1. 加载 br_netfilter 模块
sudo modprobe br_netfilter
# 2. 确认模块已加载
lsmod | grep br_netfilter
# 3. 设置开机自动加载
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF
# 4. 配置必要的系统参数
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward = 1
EOF
# 5. 应用系统参数
sudo sysctl --system
# 6. 验证参数已生效
sysctl net.bridge.bridge-nf-call-iptables
sysctl net.bridge.bridge-nf-call-ip6tables
sysctl net.ipv4.ip_forward
删除错误的 Pod，让它自动重建
kubectl delete pod -n kube-flannel kube-flannel-ds-njtqv
重建完成后查看 pod 和 node 信息
root@server-01:~# kubectl get pods -A
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-flannel kube-flannel-ds-g84gc 1/1 Running 0 18s
kube-system coredns-66bc5c9577-kr6n7 1/1 Running 0 57m
kube-system coredns-66bc5c9577-rhgnh 1/1 Running 0 57m
kube-system etcd-server-01 1/1 Running 0 57m
kube-system kube-apiserver-server-01 1/1 Running 0 57m
kube-system kube-controller-manager-server-01 1/1 Running 0 57m
kube-system kube-proxy-fm9cz 1/1 Running 0 57m
kube-system kube-scheduler-server-01 1/1 Running 0 57m
root@server-01:~# kubectl get nodes -A
NAME STATUS ROLES AGE VERSION
server-01 Ready control-plane 57m v1.34.1
pod 成功运行，node 状态 ready
