问题描述
当我们使用 kubeadm join 命令将 Node 节点加入集群时，你会发现所有 kubectl 命令均不可用（呈现阻塞状态，并不会返回响应结果），我们可以在 Node 节点中通过 kubeadm reset 命令将 Node 节点下线，此时回到 Master 节点再使用 watch kubectl get pods --all-namespaces 可以看到下图中报错了，coredns-xxx-xxx 状态为 CrashLoopBackOff
解决方案
从上面的错误信息不难看出应该是出现了网络问题，而我们在安装过程中只使用了一个网络插件 Calico ，那么该错误是不是由 Calico 引起的呢？带着这个疑问我们去到 Calico 官网再看一下它的说明，官网地址：https://docs.projectcalico.org/v3.7/getting-started/kubernetes/
在它的 Quickstart 里有两段话（属于特别提醒），截图如下：
上面这段话的主要意思是：当 kubeadm 安装完成后不要关机，继续完成后续的安装步骤；这也说明了安装 Kubernetes 的过程不要出现中断一口气搞定（不过这不是重点）(*￣rǒ￣)
上面这段话的主要意思是：如果你的网络在 192.168.0.0/16 网段中，则必须选择一个不同的 Pod 网络；恰巧咱们的网络范围（我虚拟机的 IP 范围是 192.168.141.0/24）和该网段重叠 (ノへ￣、)；好吧，当时做单节点集群时因为没啥问题而忽略了 ♪(∇*)
so，能够遇到这个问题主要是因为虚拟机 IP 范围刚好和 Calico 默认网段重叠导致的，所以想要解决这个问题，咱们就需要修改 Calico 的网段了（当然也可以改虚拟机的），换句话说就是大家重装一下 o (一︿一 +) o
按照以下标准步骤重装即可
重置 Kubernetes
kubeadm reset
# 输出如下
[reset] WARNING: Changes made to this host by 'kubeadm init' or 'kubeadm join' will be reverted.
[reset] Are you sure you want to proceed? [y/N]: y
[preflight] Running pre-flight checks
W0604 01:55:28.517280 22688 reset.go:234] [reset] No kubeadm config, using etcd pod spec to get data directory
[reset] No etcd config found. Assuming external etcd
[reset] Please manually reset etcd to prevent further issues
[reset] Stopping the kubelet service
[reset] unmounting mounted directories in "/var/lib/kubelet"
[reset] Deleting contents of stateful directories: [/var/lib/kubelet /etc/cni/net.d /var/lib/dockershim /var/run/kubernetes]
[reset] Deleting contents of config directories: [/etc/kubernetes/manifests /etc/kubernetes/pki]
[reset] Deleting files: [/etc/kubernetes/admin.conf /etc/kubernetes/kubelet.conf /etc/kubernetes/bootstrap-kubelet.conf /etc/kubernetes/controller-manager.conf /etc/kubernetes/scheduler.conf]
The reset process does not reset or clean up iptables rules or IPVS tables.
If you wish to reset iptables, you must do so manually.
For example:
iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X
If your cluster was setup to utilize IPVS, run ipvsadm --clear (or similar)
to reset your system's IPVS tables.
删除 kubectl 配置
rm -fr ~/.kube/
启用 IPVS
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
导出并修改配置文件
kubeadm config print init-defaults --kubeconfig ClusterConfiguration > kubeadm.yml
配置文件修改如下
apiVersion: kubeadm.k8s.io/v1beta1
bootstrapTokens:
- groups:
- system:bootstrappers:kubeadm:default-node-token
token: abcdef.0123456789abcdef
ttl: 24h0m0s
usages:
- signing
- authentication
kind: InitConfiguration
localAPIEndpoint:
advertiseAddress: 192.168.141.150
bindPort: 6443
nodeRegistration:
criSocket: /var/run/dockershim.sock
name: kubernetes-master-01
taints:
- effect: NoSchedule
key: node-role.kubernetes.io/master
---
apiServer:
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta1
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: "192.168.141.200:6444"
controllerManager: {}
dns:
type: CoreDNS
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.14.2
networking:
dnsDomain: cluster.local
# 主要修改在这里，替换 Calico 网段为我们虚拟机不重叠的网段（这里用的是 Flannel 默认网段）
podSubnet: "10.244.0.0/16"
serviceSubnet: 10.96.0.0/12
scheduler: {}
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
featureGates:
SupportIPVSProxyMode: true
mode: ipvs
kubeadm 初始化
kubeadm init --config=kubeadm.yml --experimental-upload-certs | tee kubeadm-init.log
# 输出如下
[init] Using Kubernetes version: v1.14.2
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Activating the kubelet service
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [kubernetes-master-01 localhost] and IPs [192.168.141.150 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [kubernetes-master-01 localhost] and IPs [192.168.141.150 127.0.0.1 ::1]
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kubernetes-master-01 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.141.150 192.168.141.200]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "admin.conf" kubeconfig file
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 24.507568 seconds
[upload-config] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.14" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Storing the certificates in ConfigMap "kubeadm-certs" in the "kube-system" Namespace
[upload-certs] Using certificate key:
a662b8364666f82c93cc5cd4fb4fabb623bbe9afdb182da353ac40f1752dfa4a
[mark-control-plane] Marking the node kubernetes-master-01 as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node kubernetes-master-01 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: abcdef.0123456789abcdef
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: CoreDNS
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[addons] Applied essential addon: kube-proxy
Your Kubernetes control-plane has initialized successfully!
To start using your cluster, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
https://kubernetes.io/docs/concepts/cluster-administration/addons/
You can now join any number of the control-plane node running the following command on each as root:
kubeadm join 192.168.141.200:6444 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:2ea8c138021fb1e184a24ed2a81c16c92f9f25c635c73918b1402df98f9c8aad \
--experimental-control-plane --certificate-key a662b8364666f82c93cc5cd4fb4fabb623bbe9afdb182da353ac40f1752dfa4a
Please note that the certificate-key gives access to cluster sensitive data, keep it secret!
As a safeguard, uploaded-certs will be deleted in two hours; If necessary, you can use
"kubeadm init phase upload-certs --experimental-upload-certs" to reload certs afterward.
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.141.200:6444 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:2ea8c138021fb1e184a24ed2a81c16c92f9f25c635c73918b1402df98f9c8aad
配置 kubectl
# 配置 kubectl
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
# 验证是否成功
kubectl get node
下载 Calico 配置文件并修改
wget https://docs.projectcalico.org/v3.7/manifests/calico.yaml
修改第 611 行，将 192.168.0.0/16 修改为 10.244.0.0/16，可以通过如下命令快速查找
- 显示行号：
:set number - 查找字符：
/要查找的字符，输入小写n下一个匹配项，输入大写N上一个匹配项
安装 Calico
kubectl apply -f calico.yaml
# 输出如下
configmap/calico-config created
customresourcedefinition.apiextensions.k8s.io/felixconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamblocks.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/blockaffinities.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamhandles.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamconfigs.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/bgppeers.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/bgpconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ippools.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/hostendpoints.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/clusterinformations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworkpolicies.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworksets.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/networkpolicies.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/networksets.crd.projectcalico.org created
clusterrole.rbac.authorization.k8s.io/calico-kube-controllers created
clusterrolebinding.rbac.authorization.k8s.io/calico-kube-controllers created
clusterrole.rbac.authorization.k8s.io/calico-node created
clusterrolebinding.rbac.authorization.k8s.io/calico-node created
daemonset.extensions/calico-node created
serviceaccount/calico-node created
deployment.extensions/calico-kube-controllers created
serviceaccount/calico-kube-controllers created
加入 Master 节点
# 示例如下，别忘记两个备用节点都要加入哦
kubeadm join 192.168.141.200:6444 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:2ea8c138021fb1e184a24ed2a81c16c92f9f25c635c73918b1402df98f9c8aad \
--experimental-control-plane --certificate-key a662b8364666f82c93cc5cd4fb4fabb623bbe9afdb182da353ac40f1752dfa4a
# 输出如下
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[preflight] Running pre-flight checks before initializing the new control plane instance
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[download-certs] Downloading the certificates in Secret "kubeadm-certs" in the "kube-system" Namespace
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kubernetes-master-02 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 192.168.141.151 192.168.141.200]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [kubernetes-master-02 localhost] and IPs [192.168.141.151 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [kubernetes-master-02 localhost] and IPs [192.168.141.151 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[certs] Using the existing "sa" key
[kubeconfig] Generating kubeconfig files
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[check-etcd] Checking that the etcd cluster is healthy
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.14" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Activating the kubelet service
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
[etcd] Announced new etcd member joining to the existing etcd cluster
[etcd] Wrote Static Pod manifest for a local etcd member to "/etc/kubernetes/manifests/etcd.yaml"
[etcd] Waiting for the new etcd member to join the cluster. This can take up to 40s
[upload-config] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[mark-control-plane] Marking the node kubernetes-master-02 as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node kubernetes-master-02 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
This node has joined the cluster and a new control plane instance was created:
* Certificate signing request was sent to apiserver and approval was received.
* The Kubelet was informed of the new secure connection details.
* Control plane (master) label and taint were applied to the new node.
* The Kubernetes control plane instances scaled up.
* A new etcd member was added to the local/stacked etcd cluster.
To start administering your cluster from this node, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
Run 'kubectl get nodes' to see this node join the cluster.
加入 Node 节点
# 示例如下
kubeadm join 192.168.141.200:6444 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:2ea8c138021fb1e184a24ed2a81c16c92f9f25c635c73918b1402df98f9c8aad
# 输出如下
> --discovery-token-ca-cert-hash sha256:2ea8c138021fb1e184a24ed2a81c16c92f9f25c635c73918b1402df98f9c8aad
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.14" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Activating the kubelet service
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
验证是否可用
kubectl get node
# 输出如下，我们可以看到 Node 节点已经成功上线 ━━(￣ー￣*|||━━
NAME STATUS ROLES AGE VERSION
kubernetes-master-01 Ready master 19m v1.14.2
kubernetes-master-02 Ready master 4m46s v1.14.2
kubernetes-master-03 Ready master 3m23s v1.14.2
kubernetes-node-01 Ready <none> 74s v1.14.2
watch kubectl get pods --all-namespaces
# 输出如下，coredns 也正常运行了
Every 2.0s: kubectl get pods --all-namespaces kubernetes-master-01: Tue Jun 4 02:31:43 2019
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system calico-kube-controllers-8646dd497f-hz5xp 1/1 Running 0 9m9s
kube-system calico-node-2z892 1/1 Running 0 9m9s
kube-system calico-node-fljxv 1/1 Running 0 6m39s
kube-system calico-node-vprlw 1/1 Running 0 5m16s
kube-system calico-node-xvqcx 1/1 Running 0 3m7s
kube-system coredns-8686dcc4fd-5ndjm 1/1 Running 0 21m
kube-system coredns-8686dcc4fd-zxtql 1/1 Running 0 21m
kube-system etcd-kubernetes-master-01 1/1 Running 0 20m
kube-system etcd-kubernetes-master-02 1/1 Running 0 6m37s
kube-system etcd-kubernetes-master-03 1/1 Running 0 5m14s
kube-system kube-apiserver-kubernetes-master-01 1/1 Running 0 20m
kube-system kube-apiserver-kubernetes-master-02 1/1 Running 0 6m37s
kube-system kube-apiserver-kubernetes-master-03 1/1 Running 0 5m14s
kube-system kube-controller-manager-kubernetes-master-01 1/1 Running 1 20m
kube-system kube-controller-manager-kubernetes-master-02 1/1 Running 0 6m37s
kube-system kube-controller-manager-kubernetes-master-03 1/1 Running 0 5m14s
kube-system kube-proxy-68jqr 1/1 Running 0 3m7s
kube-system kube-proxy-69bnn 1/1 Running 0 6m39s
kube-system kube-proxy-vvhp5 1/1 Running 0 5m16s
kube-system kube-proxy-ws6wx 1/1 Running 0 21m
kube-system kube-scheduler-kubernetes-master-01 1/1 Running 1 20m
kube-system kube-scheduler-kubernetes-master-02 1/1 Running 0 6m37s
kube-system kube-scheduler-kubernetes-master-03 1/1 Running 0 5m14s
至此，Kubernetes 高可用集群算是彻底部署成功
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