自学k8s-kubeadm部署过程中遇到的dial tcp 127.0.0.1:10251: connect: connection refused错误

问题现象

部署完master节点以后，执行kubectl get cs命令来检测组件的运行状态时，报如下错误：

[root@k8s-master yum.repos.d]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS      MESSAGE                                                                                       ERROR
scheduler            Unhealthy   Get "http://127.0.0.1:10251/healthz": dial tcp 127.0.0.1:10251: connect: connection refused   
controller-manager   Unhealthy   Get "http://127.0.0.1:10252/healthz": dial tcp 127.0.0.1:10252: connect: connection refused   
etcd-0               Healthy     {"health":"true"}                                                                             
[root@k8s-master yum.repos.d]# wget http://127.0.0.1:10251/healthz
--2020-11-14 00:10:51--  http://127.0.0.1:10251/healthz
Connecting to 127.0.0.1:10251... failed: Connection refused.

原因分析

出现这种情况，是/etc/kubernetes/manifests/下的kube-controller-manager.yaml和kube-scheduler.yaml设置的默认端口是0导致的，解决方式是注释掉对应的port即可，操作如下：

　

[root@k8s-master manifests]# ls
etcd.yaml  kube-apiserver.yaml  kube-controller-manager.yaml  kube-scheduler.yaml
[root@k8s-master manifests]# pwd
/etc/kubernetes/manifests
[root@k8s-master manifests]#

kube-controller-manager.yaml文件修改：注释掉27行
1 apiVersion: v1
2 kind: Pod
3 metadata:
4 creationTimestamp: null
5 labels:
6 component: kube-controller-manager
7 tier: control-plane
8 name: kube-controller-manager
9 namespace: kube-system
10 spec:
11 containers:
12 - command:
13 - kube-controller-manager
14 - --allocate-node-cidrs=true
15 - --authentication-kubeconfig=/etc/kubernetes/controller-manager.conf
16 - --authorization-kubeconfig=/etc/kubernetes/controller-manager.conf
17 - --bind-address=127.0.0.1
18 - --client-ca-file=/etc/kubernetes/pki/ca.crt
19 - --cluster-cidr=10.244.0.0/16
20 - --cluster-name=kubernetes
21 - --cluster-signing-cert-file=/etc/kubernetes/pki/ca.crt
22 - --cluster-signing-key-file=/etc/kubernetes/pki/ca.key
23 - --controllers=*,bootstrapsigner,tokencleaner
24 - --kubeconfig=/etc/kubernetes/controller-manager.conf
25 - --leader-elect=true
26 - --node-cidr-mask-size=24
27 # - --port=0
28 - --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt
29 - --root-ca-file=/etc/kubernetes/pki/ca.crt
30 - --service-account-private-key-file=/etc/kubernetes/pki/sa.key
31 - --service-cluster-ip-range=10.1.0.0/16
32 - --use-service-account-credentials=true

kube-scheduler.yaml配置修改：注释掉19行,- --port=0
1 apiVersion: v1
2 kind: Pod
3 metadata:
4 creationTimestamp: null
5 labels:
6 component: kube-scheduler
7 tier: control-plane
8 name: kube-scheduler
9 namespace: kube-system
10 spec:
11 containers:
12 - command:
13 - kube-scheduler
14 - --authentication-kubeconfig=/etc/kubernetes/scheduler.conf
15 - --authorization-kubeconfig=/etc/kubernetes/scheduler.conf
16 - --bind-address=127.0.0.1
17 - --kubeconfig=/etc/kubernetes/scheduler.conf
18 - --leader-elect=true
19 # - --port=0

然后在master节点上重启kubelet，systemctl restart kubelet.service，然后重新查看就正常了

[root@k8s-master manifests]# vim kube-controller-manager.yaml
[root@k8s-master manifests]# vim kube-scheduler.yaml
[root@k8s-master manifests]# vim kube-controller-manager.yaml
[root@k8s-master manifests]# systemctl restart kubelet.service
[root@k8s-master manifests]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS    MESSAGE             ERROR
scheduler            Healthy   ok                  
controller-manager   Healthy   ok                  
etcd-0               Healthy   {"health":"true"}   
[root@k8s-master manifests]#