kuberenetes 升级后新加入节点报错

问题简述

原本用kubeadm安装的的kubernetes 1.11.x集群升级到1.12.x 后（使用kubeadm upgrade升级）发现无法将新的node加入到集群中，会出现以下报错信息

[preflight] running pre-flight checks
    [WARNING RequiredIPVSKernelModulesAvailable]: the IPVS proxier will not be used, because the following required kernel modules are not loaded: [ip_vs_sh ip_vs ip_vs_rr ip_vs_wrr] or no builtin kernel ipvs support: map[ip_vs_rr:{} ip_vs_wrr:{} ip_vs_sh:{} nf_conntrack_ipv4:{} ip_vs:{}]
you can solve this problem with following methods:
 1. Run 'modprobe -- ' to load missing kernel modules;
2. Provide the missing builtin kernel ipvs support

[discovery] Trying to connect to API Server "172.19.170.254:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://172.19.170.254:6443"
[discovery] Requesting info from "https://172.19.170.254:6443" again to validate TLS against the pinned public key
[discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server "172.19.170.254:6443"
[discovery] Successfully established connection with API Server "172.19.170.254:6443"
[kubelet] Downloading configuration for the kubelet from the "kubelet-config-1.12" ConfigMap in the kube-system namespace
configmaps "kubelet-config-1.12" is forbidden: User "system:bootstrap:y1zgt7" cannot get configmaps in the namespace "kube-system"

修复方法

在master节点上执行步骤1-4，在从节点（将要加入集群的机器）上执行步骤5

步骤一

从现有的”ConfigMap kubelet-config-1.11” 创建一个新的ConfigMap “kubelet-config-1.12”

$ kubectl get cm --all-namespaces
$ kubectl -n kube-system get cm kubelet-config-1.11 -o yaml --export > kubelet-config-1.12-cm.yaml
$ vim kubelet-config-1.12-cm.yaml       #modify at the bottom:
                                        #name: kubelet-config-1.12
                                        #delete selfLink
$ kubectl -n kube-system create -f kubelet-config-1.12-cm.yaml

步骤二：获取令牌前缀

$ kubeadm token list           #if no output, then create a token:
$ kubeadm token create
TOKEN                       ...     ...
a0b1c2.svn4my9ifft4zxgg     ...     ...
# Token prefix is "a0b1c2"

步骤三

从现有角色“kubeadm：kubelet-config-1.11”创建一个新角色“kubeadm：kubelet-config-1.12”

$ kubectl get roles --all-namespaces
$ kubectl -n kube-system get role kubeadm:kubelet-config-1.11 -o yaml > kubeadm:kubelet-config-1.12-role.yaml
$ vim kubeadm\:kubelet-config-1.12-role.yaml    #modify the following:
                                                #name: kubeadm:kubelet-config-1.12
                                                #resourceNames: kubelet-config-1.12
                                                #delete creationTimestamp, resourceVersion, selfLink, uid (because --export option is not supported)    
$ kubectl -n kube-system create -f kubeadm\:kubelet-config-1.12-role.yaml

步骤四

从现有角色绑定 “kubeadm：kubelet-config-1.11” 创建一个新角色绑定 “kubeadm：kubelet-config-1.12”

$ kubectl get rolebindings --all-namespaces
$ kubectl -n kube-system get rolebinding kubeadm:kubelet-config-1.11 -o yaml > kubeadm:kubelet-config-1.12-rolebinding.yaml
$ vim kubeadm\:kubelet-config-1.12-rolebinding.yaml     #modify the following:
                                                            #metadata/name: kubeadm:kubelet-config-1.12
                                                            #roleRef/name: kubeadm:kubelet-config-1.12
                                                            #delete creationTimestamp, resourceVersion, selfLink, uid (because --export option is not supported)
- apiGroup: rbac.authorization.k8s.io                       #add these 3 lines as another group in "subjects:" at the bottom, with the 6 character token prefix from STEP 2
  kind: Group
  name: system:bootstrap:a0b1c2 
$ kubectl -n kube-system create -f kubeadm\:kubelet-config-1.12-rolebinding.yaml

步骤5：从工作节点启动kubeadm join

1
2
3

$ sudo kubeadm join --token <token> <master-IP>:6443 --discovery-token-ca-cert-hash sha256:<key-value> 
# If you receive 2 ERRORS, run kubeadm join again with the following options:
$ sudo kubeadm join --token <token> <master-IP>:6443 --discovery-token-ca-cert-hash sha256:<key-value> --ignore-preflight-errors=FileAvailable--etc-kubernetes-bootstrap-kubelet.conf,FileAvailable--etc-kubernetes-pki-ca.crt

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