【kubernetes 问题排查】使用 kubeadm 部署问题汇总

目录

• 引言
• 问题汇总
  • • The connection to the server localhost:8080 was refused - did you specify the right host or port?
    • kubectl get cs 出现 Unhealthy
    • failed to run Kubelet: misconfiguration: kubelet cgroup driver: “systemd“ is different from docker
    • Unable to connect to the server: x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kubernetes")
    • Kubeadm：如何解决kubectl get cs显示scheduler Unhealthy，controller-manager Unhealthy
    • 解决 Kubernetes 中 Kubelet 组件报 failed to get cgroup 错误
    • 解决k8s"failed to set bridge addr: "cni0" already has an IP address different from 10.244.1.1/24"
    • 排查coredns 解析不到domain
    • 集群证书到期
• 部署高可用 HAProxy
  • • Haproxy
    • Keepalived

引言

再使用kubeadm部署集群时会多少遇到一些问题，这里做下记录，方便后面查找问题时有方向，同时也为刚要入坑的你指明下方向，让你少走点弯路

问题汇总

The connection to the server localhost:8080 was refused - did you specify the right host or port?

# root 用户
  export KUBECONFIG=/etc/kubernetes/admin.conf
 
# 非root
  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

kubectl get cs 出现 Unhealthy

修改 /etc/kubernetes/manifests/kube-scheduler.yaml 和 /etc/kubernetes/manifests/kube-controller-manager.yaml 注释掉 - --port=0

failed to run Kubelet: misconfiguration: kubelet cgroup driver: “systemd“ is different from docker

{
  "exec-opts": ["native.cgroupdriver=systemd"], 
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2",
  "storage-opts": [
    "overlay2.override_kernel_check=true"
  ] 
}

Unable to connect to the server: x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kubernetes")

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
kubectl get nodes
export KUBECONFIG=/etc/kubernetes/kubelet.conf
kubectl get node

Kubeadm：如何解决kubectl get cs显示scheduler Unhealthy，controller-manager Unhealthy

root用户
配置文件路径为：
/etc/kubernetes/manifests/kube-scheduler.yaml
/etc/kubernetes/manifests/kube-controller-manager.yaml
user账号
$HOME/.kube/
将两个配置文件中 –port 注释掉

解决 Kubernetes 中 Kubelet 组件报 failed to get cgroup 错误

http://www.mydlq.club/article/80/

解决k8s"failed to set bridge addr: "cni0" already has an IP address different from 10.244.1.1/24"

具体原因

ifconfig cni0 down
ip link delete cni0

• 查看kubelet日志

journalctl -xeu kubelet

排查coredns 解析不到domain

思路：在pod中使用 ping/dig 进行测试，由于集群是一个扁平化的网络在集群节点上可以互通,故可以使用coredns ip进行测试

使用dig @<coredns ip> baidu.com +trace 进行

集群证书到期

更新证书

kubeadm certs renew all # 注意不更新kubelet的

更新kubelet证书，默认采用证书轮换自动续期，如果已经到期了需要重新生成kubelet.conf

mv /etc/kubernetes/kubelet.conf .
mv /var/lib/kubelet/pki/kubelet-client* .
# 替换NODE为节点名称 可能需要--config kubeadm.conf
kubeadm config print init-defaults > kubeadm.conf
kubeadm kubeconfig user --org system:nodes --client-name system:node:$NODE --config /root/kubeadm.conf> kubelet.conf
# 修改kubelet.conf apiserver 
cp kubelet.conf /etc/kubernetes/kubelet.conf
systemctl restart kubelet

https://v1-22.docs.kubernetes.io/docs/setup/production-environment/tools/kubeadm/troubleshooting-kubeadm/#kubelet-client-cert

部署高可用 HAProxy

Haproxy

<details>
<summary>查看 haproxy.cfg 配置文件</summary>
 
``` bash
global
log 127.0.0.1 local0
log 127.0.0.1 local1 notice
maxconn 4096
#chroot /usr/share/haproxy
#user haproxy
#group haproxy
#daemon
stats socket /var/lib/haproxy/stats
 
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000
 
frontend kube-apiserver
bind *:6444
mode tcp
timeout client 1h
log global
option tcplog
 
default_backend kube-apiserver
 
 
 
backend kube-apiserver
option httpchk GET /healthz
http-check expect status 200
mode tcp
option ssl-hello-chk
balance     roundrobin
balance roundrobin
  server k8s-master01 192.168.4.41:6443 check #主要配置这里
  server k8s-master02 192.168.4.42:6443 check
  server k8s-master03 172.17.0.66:6443 check
 
```
</details>
 
``` bash
docker run -d --restart=always --name haproxy -p 6444:6444 \
    -v ~/haproxy.cfg:/usr/local/etc/haproxy/haproxy.cfg \
    haproxy
```

Keepalived

• ip address associated with VRID 160 not present in MASTER advert : xx.xx.xx.xx

  可能是keepalive master的virtual_router_id和局域网内的其它的keepalive master的virtual_router_id有冲突
  修改 /etc/keepalived/keepalived.conf 中的 virtual_router_id 重启即可

• 配置文件详解

https://blog.csdn.net/u012758088/article/details/76599500

  #!/bin/bash
  VIRTUAL_IP=192.168.4.200 # 设置虚拟IP
  INTERFACE=eth0 #所使用的的网卡
  NETMASK_BIT=24
  CHECK_PORT=6444
  RID=10
  VRID=160 #虚拟路由ID 需要唯一
  MCAST_GROUP=224.0.0.18
 
  docker run -itd --restart=always --name=Keepalived-K8S \
          --net=host --cap-add=NET_ADMIN \
          -e VIRTUAL_IP=$VIRTUAL_IP \
          -e INTERFACE=$INTERFACE \
          -e CHECK_PORT=$CHECK_PORT \
          -e RID=$RID \
          -e VRID=$VRID \
          -e NETMASK_BIT=$NETMASK_BIT \
          -e MCAST_GROUP=$MCAST_GROUP \
          wise2c/keepalived-k8s

使用 ip addr 即可看到所设置网卡上的虚拟IP(PS:ifconfig是看不到的)