Kubernetes:Nodes/Pods在用kubeadm构建集群后没有用kubectl显示

Question

我正在尝试使用kubeadm工具创建一个Kubernetes cluster。为此，我安装了此处指定的受支持的docker version

我也可以成功安装kubeadm。我用以下命令启动了集群

sudo kubeadm init --pod-network-cidr=10.244.0.0/14 --apiserver-advertise-address=172.16.0.11

我得到了使用kubeadm join加入集群的消息，如下所示

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/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 172.16.0.11:6443 --token ptdibx.r2uu0s772n6fqubc 
--discovery-token-ca-cert-hash sha256:f3e36a8e82fb8166e0faf407235f12e256daf87d0a6d0193394f4ce31b50255c   

用于网络目的的flannel

$ kubectl apply -f    https://raw.githubusercontent.com/coreos/flannel/2140ac876ef134e0ed5af15c65e414cf26827915/Documentation/kube-flannel.yml
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds-amd64 created
daemonset.apps/kube-flannel-ds-arm64 created

之后，当我尝试检查kubectl命令以检查pods/nodes状态时，它失败了

$ sudo kubectl get nodes
error: no configuration has been provided, try setting KUBERNETES_MASTER environment variable
$ sudo kubectl get pods --all-namespaces
error: no configuration has been provided, try setting KUBERNETES_MASTER environment variable
$ echo $KUBECONFIG 
/etc/kubernetes/admin.conf:/home/ltestzaman/.kube/config

Docker和kubernetes版本如下：

$ sudo kubeadm version
kubeadm version: &version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.2",      
GitCommit:"52c56ce7a8272c798dbc29846288d7cd9fbae032", GitTreeState:"clean",  
BuildDate:"2020-04-16T11:54:15Z", GoVersion:"go1.13.9", Compiler:"gc", Platform:"linux/amd64"}
$ sudo docker version
Client:
Version:      17.03.0-ce
API version:  1.26
Go version:   go1.7.5
Git commit:   3a232c8
Built:        Tue Feb 28 08:10:07 2017
OS/Arch:      linux/amd64
Server:
Version:      17.03.0-ce

如何使集群工作？

admin.conf的输出如下：

$ sudo cat /etc/kubernetes/admin.conf
apiVersion: v1
clusters:
- cluster:
certificate-authority-data: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSUN5RENDQWJDZ0F3SUJBZ0lCQURBTkJna3Foa2lHOXcwQkFRc0ZBREFWTVJNd0VRWURWUVFERXdwcmRXSmwKY201bGRHVnpN
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UWd4TGsyWE05K0pxc0hYRkRPWHB2YXYxdXNyeXNYMldOZzlOOVFaeDVucFA2UTRpYkQrZDFjWFcyL0oKY0ZXUjhBSDliaG5hZlhLRUhiUVZWT0R2UTcwbFRmNXVtVlQ4Qk5ZUjRQTmlCWjFxVDNMNnduWlYrekl6a0ZKMwp0
eVVNK0prUy80K2dMazI3b01HMFZ4Rnpjd1ozREMxWEFqRXVxb3FrYVF5UGUzMk9XZmZ2N082TjhxeWNCNkdnClNxbWxNWldBMk1DL0J1cFpZWXRYNkUyYUtNUloxZjkzRlpCaFdYNG9DYjVQSGdSUEdoNTFiNERKZExoYlk4
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K2g1U09Ddms1YncwbEYKODhZNnlTaHk3U1B6amRNUHdRcks5cmhWY1ZXK1VvS3d6SE80aUZHdWpmNDR0WHRydTY4L1NGVm5uVnRHWkYyKwo2WmJYeE81Z3I2c1NBQU9NK0E1RmtkQlNmcXZDdmwvUzZFQk04V2czaGNjOUZL
cEFCV0tadHNoRlMxOD0KLS0tLS1FTkQgQ0VSVElGSUNBVEUtLS0tLQo=
server: https://172.16.0.11:6443
name: kubernetes
contexts:contexts:
- context:
cluster: kubernetes
user: kubernetes-admin
name: kubernetes-admin@kubernetes
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:
- name: kubernetes-admin
user:
client-certificate-data: LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSUM4akNDQWRxZ0F3SUJBZ0lJS2RLRGs4MUpNKzh3RFFZSktvWklodmNOQVFFTEJRQXdGVEVUTUJFR0ExVUUKQXhNS2EzVmlaWEp
1WlhSbGN6QWVGdzB5TURBME1UZ3hNelU0TXpKYUZ3MHlNVEEwTVRneE16VTRNelphTURReApGekFWQmdOVkJBb1REbk41YzNSbGJUcHRZWE4wWlhKek1Sa3dGd1lEVlFRREV4QnJkV0psY201bGRHVnpMV0ZrCmJXbHVNSUl
CSWpBTkJna3Foa2lHOXcwQkFRRUZBQU9DQVE4QU1JSUJDZ0tDQVFFQW44elI0RlVVM2F1QjluVGkKeWxJV1ZpZ3JkV1dHSXY0bmhsRnZuQU1mWVJyVklrMGN6eTZPTmZBQzNrb01tZ3ZPQnA5MmpsWmlvYXpJUGg1aAovaUR
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1TkNkeWp1cQpIVzQrMU5HdWZSczJWZW1kaGZZN2VORDJrSnJXNldHUnYyeWlBbDRQUGYzYURVbGpFYm9jVmx0RjZHTXhRRVU2CkJtaEJUWGMrVndaSXRzVnRPNTUzMHBDSmZwamJrRFZDZWFFUlBYK2RDd3hiTnh0ZWpacGZ
XT28zNGxTSGQ3TFYKRDc5UHAzYW1qQXpyamFqZE50QkdJeHFDc3lZWE9Rd1BVL2Nva1RJVHRHVWxLTVV5aUdOQk5rQ3NPc3RiZHI2RApnQVRuREg5YWdNck9CR2xVaUlJN0Qvck9rU3IzU2QvWnprSGdMM1c4a3V5dXFUWWp
wazNyNEFtU3NXS1M4UUdNCjZ6bHUwRk4rYnVJbGRvMnBLNmhBZlBnSTBjcDZWQWk1WW5lQVVGQ2EyL2pJeXI3cXRiND0KLS0tLS1FTkQgQ0VSVElGSUNBVEUtLS0tLQo=
client-key-data: LS0tLS1CRUdJTiBSU0EgUFJJVkFURSBLRVktLS0tLQpNSUlFb3dJQkFBS0NBUUVBbjh6UjRGVVUzYXVCOW5UaXlsSVdWaWdyZFdXR0l2NG5obEZ2bkFNZllSclZJazBjCnp5Nk9OZkFDM2tvTW1
ndk9CcDkyamxaaW9heklQaDVoL2lEcWpRN3czeHBYVDdUMU9ZMksvZlcrdUtTUVFSN1UKTHVuMzgxMGhjVlFKbk1mZXhQYmxzNjZHdE94T1YvZFBtbXBBMlBZcy9JcFlrS1BIajZzb29DV1NSRDFGSHhtUgp1YWFheGkvSFh
Bd0k4NkQ3TW5ZL3QrNklBUjIrNlEzS2NqT0RXRFpUaWx2MjFwQlhQWnVvRU53aGdLNm1oSlFOClVGZzlWZUU0Q3g0SkQrYVhuYVJRbTMyd2J3b2hheTU4Ny9BZ1I0aDMzV04zSENYT1RlKytmeHpYQ0Z4cE9TVGIKbXc2TDV
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BZjZUMzM4Tjg5ZEo2Wi93QUlOdWNYCi0tLS0tRU5EIFJTQSBQUklWQVRFIEtFWS0tLS0tCg==

不确定为什么大多数条目都是null，如下所示

$ sudo kubectl config view
apiVersion: v1
clusters: null
contexts: null
current-context: ""
kind: Config
preferences: {}
users: null

Answer 1

很可能kubeconfig文件设置不正确。

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

或者，如果你是root用户，你可以运行：

export KUBECONFIG=/etc/kubernetes/admin.conf

这也应该工作

sudo kubectl get nodes --kubeconfig=/etc/kubernetes/admin.conf 

Answer 2

将环境变量KUBECONFIG更改为/home/ltestzaman/.kube/config，它可以进行

$ echo $KUBECONFIG 
/home/ltestzaman/.kube/config
$ kubectl get nodes --all-namespaces
NAME             STATUS   ROLES    AGE    VERSION
kubemaster-001   Ready    master   117m   v1.18.2

或者需要提及——由@Arghya Sadhu 识别的配置

$ sudo kubectl get nodes --kubeconfig=/etc/kubernetes/admin.conf
NAME             STATUS   ROLES    AGE    VERSION
kubemaster-001   Ready    master   120m   v1.18.2

Answer 3

您必须启动kubernetes集群。使用minikube start，或者如果您正在连接任何云服务，请确保kubernetes已启动。