CentOS7使用kubeadm安装k8s

2022-04-26 本文已影响0人张氏小毛驴

CentOS7使用kubeadm安装k8s

0.前言

文章使用的k8s版本为1.10.0

系统为CentOS7

总共有三台机器：

Name	IP	Role
ceph1	172.16.32.70	Master
ceph2	172.16.32.107	Node
ceph3	172.16.32.71	Node

1.准备工作

Master和Node中都需要操作的：

环境问题
- 添加hostname
```
[root@ceph1 ~]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

172.16.32.70 ceph1
172.16.32.107 ceph2
172.16.32.71 ceph3
```
- 关闭防火墙
  
  systemctl stop firewalld
  
  systemctl disable firewalld
- 禁用SELINUX
  
  sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/sysconfig/selinux
  
  setenforce 0
  
  这里/etc/sysconfig/selinux中SELINUX=enforcing这一项不一定默认是这个，也可能是permissive，最好就是打开文件进行修改为disabled。
- 关闭swap
  
  swapoff -a
  
  上述命令在系统重启后会失效，可以修改配置文件达到永久关闭swap：
  
  打开/etc/fstab,注释掉有关swap的那一句:
  
  /dev/mapper/centos-swap swap swap defaults 0 0
- 设置系统路由参数,创建/etc/sysctl.d/k8s.conf ,添加以下内容
```
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
```
  添加完成后，执行以下命令使修改能生效：
  
  modprobe br_netfilter
  
  sysctl -p /etc/sysctl.d/k8s.conf

安装docker

安装命令

yum install -y docker
systemctl start docker
systemctl enable docker

添加docker加速器和私有镜像仓库地址

[root@ceph1 ~]# cat /etc/docker/daemon.json 
{
  "registry-mirrors": ["https://p7t6rz3f.mirror.aliyuncs.com"],
  "insecure-registries": ["172.16.32.48:5000"]
}

重新加载启动docker服务

systemctl daemon-reload
systemctl restart docker

安装kubeadm，kubelet，kubectl
- 添加阿里云源
```
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
        http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
```
- 开始安装
  
  yum makecache fast && yum install -y kubelet-1.10.0-0 kubeadm-1.10.0-0 kubectl-1.10.0-0
- 配置kubelet
  
  1.首先查看docker的Cgroup类型，docker info |grep Cgroup ,kubelet配置文件的**KUBELET_CGROUP_ARGS=--cgroup-driver=xxx **需要与docker的一致，如果不一致就修改。
  
  2.添加一句Environment="KUBELET_EXTRA_ARGS=--fail-swap-on=false"
  
  原因是：更改系统要关闭swap这个限制。
  
  3.重新加载服务systemctl daemon-reload

2.开始集群安装

由于无法拉取k8s.gcr.io的镜像，需要本地先拉取，再修改tag

将拉取镜像并修改tag的操作写入到一个shell脚本里：

master:

#!/bin/bash

docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/etcd-amd64:3.1.12
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/flannel:v0.10.0-amd64
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-apiserver-amd64:v1.10.0
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-scheduler-amd64:v1.10.0
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-controller-manager-amd64:v1.10.0
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-proxy-amd64:v1.10.0
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/k8s-dns-kube-dns-amd64:1.14.8
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/k8s-dns-dnsmasq-nanny-amd64:1.14.8
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/k8s-dns-sidecar-amd64:1.14.8
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/pause-amd64:3.1

docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/etcd-amd64:3.1.12 k8s.gcr.io/etcd-amd64:3.1.12
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/flannel:v0.10.0-amd64 quay.io/coreos/flannel:v0.10.0-amd64
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-apiserver-amd64:v1.10.0 k8s.gcr.io/kube-apiserver-amd64:v1.10.0
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-scheduler-amd64:v1.10.0 k8s.gcr.io/kube-scheduler-amd64:v1.10.0
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-controller-manager-amd64:v1.10.0 k8s.gcr.io/kube-controller-manager-amd64:v1.10.0
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-proxy-amd64:v1.10.0 k8s.gcr.io/kube-proxy-amd64:v1.10.0
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/k8s-dns-kube-dns-amd64:1.14.8 k8s.gcr.io/k8s-dns-kube-dns-amd64:1.14.8
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/k8s-dns-dnsmasq-nanny-amd64:1.14.8 k8s.gcr.io/k8s-dns-dnsmasq-nanny-amd64:1.14.8
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/k8s-dns-sidecar-amd64:1.14.8 k8s.gcr.io/k8s-dns-sidecar-amd64:1.14.8
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/pause-amd64:3.1 k8s.gcr.io/pause-amd64:3.1

node:

#!/bin/bash

docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-proxy-amd64:v1.10.0
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/flannel:v0.10.0-amd64
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/pause-amd64:3.1
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kubernetes-dashboard-amd64:v1.8.3
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/heapster-influxdb-amd64:v1.3.3
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/heapster-grafana-amd64:v4.4.3
docker pull registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/heapster-amd64:v1.5.3

docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/flannel:v0.10.0-amd64 quay.io/coreos/flannel:v0.10.0-amd64
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/pause-amd64:3.1 k8s.gcr.io/pause-amd64:3.1
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kube-proxy-amd64:v1.10.0 k8s.gcr.io/kube-proxy-amd64:v1.10.0
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/kubernetes-dashboard-amd64:v1.8.3 k8s.gcr.io/kubernetes-dashboard-amd64:v1.8.3
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/heapster-influxdb-amd64:v1.3.3 k8s.gcr.io/heapster-influxdb-amd64:v1.3.3
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/heapster-grafana-amd64:v4.4.3 k8s.gcr.io/heapster-grafana-amd64:v4.4.3
docker tag registry.cn-hangzhou.aliyuncs.com/zhanye-zhang/heapster-amd64:v1.5.3 k8s.gcr.io/heapster-amd64:v1.5.3

在Master执行初始化

kubeadm init --kubernetes-version=v1.10.0 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=172.16.32.70

这里的参数：

--kubernetes-version 集群版本

--pod-network-cidr Pod网段（后续使用flannel作为网络插件)

--apiserver-advertise-address apiserver的通信地址(Master的IP地址)

等待几分钟，就可以安装完成。。提示信息如下：

[root@localhost init]# kubeadm init --kubernetes-version=v1.10.0 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=172.16.32.70
[init] Using Kubernetes version: v1.10.0
[init] Using Authorization modes: [Node RBAC]
[preflight] Running pre-flight checks.
        [WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
        [WARNING FileExisting-crictl]: crictl not found in system path
Suggestion: go get github.com/kubernetes-incubator/cri-tools/cmd/crictl
[preflight] Starting the kubelet service
[certificates] Generated ca certificate and key.
[certificates] Generated apiserver certificate and key.
[certificates] apiserver serving cert is signed for DNS names [ceph1 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 172.16.32.70]
[certificates] Generated apiserver-kubelet-client certificate and key.
[certificates] Generated etcd/ca certificate and key.
[certificates] Generated etcd/server certificate and key.
[certificates] etcd/server serving cert is signed for DNS names [localhost] and IPs [127.0.0.1]
[certificates] Generated etcd/peer certificate and key.
[certificates] etcd/peer serving cert is signed for DNS names [ceph1] and IPs [172.16.32.70]
[certificates] Generated etcd/healthcheck-client certificate and key.
[certificates] Generated apiserver-etcd-client certificate and key.
[certificates] Generated sa key and public key.
[certificates] Generated front-proxy-ca certificate and key.
[certificates] Generated front-proxy-client certificate and key.
[certificates] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/admin.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/kubelet.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/controller-manager.conf"
[kubeconfig] Wrote KubeConfig file to disk: "/etc/kubernetes/scheduler.conf"
[controlplane] Wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/manifests/kube-apiserver.yaml"
[controlplane] Wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/manifests/kube-controller-manager.yaml"
[controlplane] Wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/manifests/kube-scheduler.yaml"
[etcd] Wrote Static Pod manifest for a local etcd instance to "/etc/kubernetes/manifests/etcd.yaml"
[init] Waiting for the kubelet to boot up the control plane as Static Pods from directory "/etc/kubernetes/manifests".
[init] This might take a minute or longer if the control plane images have to be pulled.
[apiclient] All control plane components are healthy after 23.003060 seconds
[uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[markmaster] Will mark node ceph1 as master by adding a label and a taint
[markmaster] Master ceph1 tainted and labelled with key/value: node-role.kubernetes.io/master=""
[bootstraptoken] Using token: nz9430.5xujb6kf7pcu5qkw
[bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstraptoken] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstraptoken] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[addons] Applied essential addon: kube-dns
[addons] Applied essential addon: kube-proxy

Your Kubernetes master 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 machines by running the following on each node
as root:

  kubeadm join 172.16.32.70:6443 --token nz9430.5xujb6kf7pcu5qkw --discovery-token-ca-cert-hash sha256:7e6af34aa62a2fa79c8f6e56781193b7ebbabd0e883b099a378f850686bd9730

根据提示To start using your cluster, you need to run the following as a regular user操作

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

验证集群

[root@localhost init]# kubectl get nodes
NAME      STATUS    ROLES     AGE       VERSION
ceph1     NotReady     master    2h        v1.10.0

在还没安装Pod的网络插件前，get nodes 都会显示是NotReady

3.安装网络插件

下载官方yaml文件

wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

由于之前已经把官方的镜像下载好，这里不需要修改镜像地址

执行

kubectl create -f kube-flannel.yaml

过一会使用命令kubectl get pods -n kube-system 查看：

[root@localhost init]# kubectl get pods -n kube-system
NAME                                    READY     STATUS    RESTARTS   AGE
etcd-ceph1                              1/1       Running   0          3h
kube-apiserver-ceph1                    1/1       Running   0          2h
kube-controller-manager-ceph1           1/1       Running   0          2h
kube-dns-86f4d74b45-2cdgj               3/3       Running   0          3h
kube-flannel-ds-amd64-n7gdx             1/1       Running   0          2h
kube-proxy-2r6wl                        1/1       Running   0          3
kube-scheduler-ceph1                    1/1       Running   0          3h

所有Pod都处于Running状态，再次执行kubectl get nodes可看到Master已经变为Ready。

4.节点加入集群

以上步骤除了准备工作以及node下载镜像的shell脚本外，其他都是在Master上操作。在Master已经部署好的前提下，将Node节点加入集群(执行master初始化成功后输出的命令)：

kubeadm join 172.16.32.70:6443 --token nz9430.5xujb6kf7pcu5qkw --discovery-token-ca-cert-hash sha256:7e6af34aa62a2fa79c8f6e56781193b7ebbabd0e883b099a378f850686bd9730

过一会，在Master上查看node：

[root@localhost init]# kubectl get nodes
NAME      STATUS    ROLES     AGE       VERSION
ceph1     Ready     master    2h        v1.10.0
ceph2     Ready     <none>    2h        v1.10.0
ceph3     Ready     <none>    2h        v1.10.0

5.验证DNS是否正常

创建一个Pod验证

apiVersion: v1
kind: Pod
metadata:
  name: busybox
  namespace: default
spec:
  containers:
  - name: busybox
    image: busybox
    command:
      - sleep
      - "3600"
    imagePullPolicy: IfNotPresent
  restartPolicy: Always

执行

kubectl create -f busybox.yaml

验证

等待busybox的Pod状态变为Running时执行：

kubectl exec -ti busybox -- nslookup kubernetes.default

如果输出：

[root@localhost test]# kubectl exec -ti busybox -- nslookup kubernetes.default
Server:    10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local

Name:      kubernetes.default
Address 1: 10.96.0.1 kubernetes.default.svc.cluster.local

表示DNS正常工作。

CentOS7使用kubeadm安装k8s