使用kubeadm部署kubernetes集群
通过docker,我们可以在单个主机上快速部署各个应用,但是实际的生产环境里,不会单单存在一台主机,这就需要用到docker集群管理工具了,本文将简单介绍使用docker集群管理工具kubernetes进行集群部署。
1 环境规划与准备
本次搭建使用了三台主机,其环境信息如下:
| 节点功能 | 主机名 | IP |
| ——————|:—————-:|——————-:|
| master | master |192.168.1.11 |
| slave1 | slave1 |192.168.1.12 |
| slave2 | slave2 |192.168.1.13 |
在三台主机的/etc/hosts文件中添加以下内容
vim /etc/hosts #添加以下信息 192.168.1.11 master 192.168.1.12 slave1 192.168.1.13 slave2
关闭swap
swapoff -a
再把/etc/fstab文件中带有swap的行注释。
关闭SELinux
setenforce 0 vim /etc/sysconfig/selinux #修改SELINUX属性 SELINUX=disabled
设置iptables
cat <<EOF > /etc/sysctl.d/k8s.conf > net.bridge.bridge-nf-call-ip6tables = 1 > net.bridge.bridge-nf-call-iptables = 1 > EOF sysctl --system
安装socat等工具
yum install -y ebtables socat
2 kubernetes安装
2.1 安装docker
官方推荐安装docker版本为1.12
#yum安装docker yum install -y docker #设置docker开机启动 systemctl enable docker #启动docker systemctl start docker
验证docker版本
docker --version #以下为输出的版本信息 Docker version 1.12.6, build 85d7426/1.12.6
2.2 安装kubectl、kubelet、kubeadm
2.2.1 添加yum源
常用yum源均没有这几个安装包,需要添加专门的yum源
cat <<EOF > /etc/yum.repos.d/kubernetes.repo [kubernetes] name=Kubernetes baseurl= enabled=1 gpgcheck=0 EOF #官方文档中的yum源为google,国内无法使用
2.2.2 安装kubectl、kubelet、kubeadm
yum install -y kubelet kubeadm kubectl
2.2.3 启动kubelet
#设置开机启动kubelet systemctl enable kubelet #启动kubelet systemctl start kubelet
查询kubelet的状态
systemctl status kubelet
初次安装的情况下kubelet应未启动成功,我们会按下面的步骤初始化集群后会自动启动的。
3 kubernetes集群配置
3.1 master节点配置
3.1.1 初始化master
根据官方文档进行初始化:
kubeadm init --apiserver-advertise-address 192.168.1.11 --pod-network-cidr 10.244.0.0/16 #--apiserver-advertise-address 192.168.1.11为master节点IP,部分文档也指定为0.0.0.0 #--pod-network-cidr 10.244.0.0/16为pod网络cidr
出现如下错误:
[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters. unable to get URL "https://storage.googleapis.com/kubernetes-release/release/stable-1.7.txt": Get https://storage.googleapis.com/kubernetes-release/release/stable-1.7.txt: net/http: TLS handshake timeout
需要指定kubernetes-version。
首先查询版本
kubeadm versionkubeadm version: &version.Info{Major:"1", Minor:"7", GitVersion:"v1.7.5",…………
版本为1.7.5,然后启动参数中加入版本:
kubeadm init --apiserver-advertise-address 192.168.1.11 --pod-network-cidr 10.244.0.0/16 --kubernetes-version=v1.7.5
3.1.2 master节点依赖镜像
执行过程中会卡在如下步骤:
[apiclient] Created API client, waiting for the control plane to become ready
因为kubenetes初始化启动会依赖某些镜像,而这些镜像默认会到google下载,我们需要手动下载下来这些镜像后再进行初始化。
使用CTRL+C结束当前进程,然后到/etc/kubernetes/manifests/目录下查看各个yaml文件,还有其他需要的镜像文件,汇总后如下:
gcr.io/google_containers/etcd-amd64:3.0.17 gcr.io/google_containers/kube-apiserver-amd64:v1.7.5 gcr.io/google_containers/kube-controller-manager-amd64:v1.7.5 gcr.io/google_containers/kube-scheduler-amd64:v1.7.5 gcr.io/google_containers/pause-amd64:3.0 gcr.io/google_containers/kube-proxy-amd64:v1.7.5 quay.io/coreos/flannel gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4 gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4 gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4
因直接下载这些google镜像,下载不下来,我们通过下载dockerHUB/阿里云上的镜像,然后更改tag。
#etcd-amd64:3.0.17 docker pull sylzd/etcd-amd64-3.0.17 docker tag docker.io/sylzd/etcd-amd64-3.0.17:latest gcr.io/google_containers/etcd-amd64:3.0.17 #kube-apiserver-amd64:v1.7.5 docker pull registry.cn-hangzhou.aliyuncs.com/google-containers/kube-apiserver-amd64:v1.7.5 docker tag registry.cn-hangzhou.aliyuncs.com/google-containers/kube-apiserver-amd64:v1.7.5 gcr.io/google_containers/kube-apiserver-amd64:v1.7.5#kube-controller-manager-amd64:v1.7.5 docker pull registry.cn-hangzhou.aliyuncs.com/google-containers/kube-controller-manager-amd64:v1.7.5 docker tag registry.cn-hangzhou.aliyuncs.com/google-containers/kube-controller-manager-amd64:v1.7.5 gcr.io/google_containers/kube-controller-manager-amd64:v1.7.5#kube-scheduler-amd64:v1.7.5 docker pull registry.cn-hangzhou.aliyuncs.com/google-containers/kube-scheduler-amd64:v1.7.5 docker tag registry.cn-hangzhou.aliyuncs.com/google-containers/kube-scheduler-amd64:v1.7.5 gcr.io/google_containers/kube-scheduler-amd64:v1.7.5#pause-amd64:3.0 docker pull visenzek8s/pause-amd64:3.0docker tag visenzek8s/pause-amd64:3.0 gcr.io/google_containers/pause-amd64:3.0#kube-proxy-amd64:v1.7.5 docker pull mirrorgooglecontainers/kube-proxy-amd64:v1.7.5 docker tag mirrorgooglecontainers/kube-proxy-amd64:v1.7.5 gcr.io/google_containers/kube-proxy-amd64:v1.7.5 #quay.io/coreos/flannel docker pull quay.io/coreos/flannel #k8s-dns-kube-dns-amd64:1.14.4 docker pull registry.cn-hangzhou.aliyuncs.com/google-containers/k8s-dns-kube-dns-amd64:1.14.4 docker tag registry.cn-hangzhou.aliyuncs.com/google-containers/k8s-dns-kube-dns-amd64:1.14.4 gcr.io/google_containers/k8s-dns-kube-dns-amd64:1.14.4#k8s-dns-sidecar-amd64:1.14.4 docker pull registry.cn-hangzhou.aliyuncs.com/google-containers/k8s-dns-sidecar-amd64:1.14.4 docker tag registry.cn-hangzhou.aliyuncs.com/google-containers/k8s-dns-sidecar-amd64:1.14.4 gcr.io/google_containers/k8s-dns-sidecar-amd64:1.14.4#k8s-dns-dnsmasq-nanny-amd64:1.14.4 docker pull mirrorgooglecontainers/k8s-dns-dnsmasq-nanny-amd64:1.14.4 docker tag mirrorgooglecontainers/k8s-dns-dnsmasq-nanny-amd64:1.14.4 gcr.io/google_containers/k8s-dns-dnsmasq-nanny-amd64:1.14.4
master节点初始化成功,结果如下:
Your Kubernetes master has initialized successfully!To start using your cluster, you need to run (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: http://kubernetes.io/docs/admin/addons/You can now join any number of machines by running the following on each nodeas root: kubeadm join --token 3f1db4.9f7ba7d52de40996 192.168.1.11:6443
需要记住kubeadm join —token这句,后面会用到
3.1.3 kubectl配置
#对于非root用户 mkdir -p $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config #对于root用户 export KUBECONFIG=/etc/kubernetes/admin.conf
3.1.4 pod network配置
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.9.1/Documentation/kube-flannel.yml
安装完network之后,你可以通过kubectl get pods —all-namespaces来查看kube-dns是否在running来判断network是否安装成功。
kubectl get pods --all-namespaces #运行正常的结果如下: NAMESPACE NAME READY STATUS RESTARTS AGEkube-system etcd-localhost.localdomain 1/1 Running 0 1hkube-system kube-apiserver-localhost.localdomain 1/1 Running 0 1hkube-system kube-controller-manager-localhost.localdomain 1/1 Running 3 1hkube-system kube-dns-2425271678-27g6v 3/3 Running 0 1hkube-system kube-flannel-ds-1mjq3 1/1 Running 1 1hkube-system kube-proxy-mtjwb 1/1 Running 0 1hkube-system kube-scheduler-localhost.localdomain 1/1 Running 0 1h
如果以上STATUS中存在不是Running的需要再进行解决。
由于安全原因,默认情况下pod不会被schedule到master节点上,可以通过下面命令解除这种限制:
kubectl taint nodes --all node-role.kubernetes.io/master-
3.2 slave节点配置
3.2.1 slave节点依赖镜像
slave节点需要以下镜像:
gcr.io/google_containers/kube-proxy-amd64:v1.7.5 quay.io/coreos/flannel gcr.io/google_containers/pause-amd64:3.0
在msater节点上导出镜像
docker save -o /opt/kube-pause.tar gcr.io/google_containers/pause-amd64:3.0 docker save -o /opt/kube-proxy.tar gcr.io/google_containers/kube-proxy-amd64:v1.7.5 docker save -o /opt/kube-flannel.tar quay.io/coreos/flannel
复制到slave主机/opt目录下,再导入即可:
docker load -i /opt/kube-flannel.tardocker load -i /opt/kube-proxy.tardocker load -i /opt/kube-pause.tar
3.2.2 slave节点加入集群
在两个slave节点上执行:
kubeadm join --token 3f1db4.9f7ba7d52de40996 192.168.1.11:6443
执行成功标志:
Node join complete:* Certificate signing request sent to master and response received.* Kubelet informed of new secure connection details.Run 'kubectl get nodes' on the master to see this machine join.
在mster节点上执行kubectl get nodes查看是否成功:
kubectl get nodesNAME STATUS AGE VERSIONmaster Ready 56m v1.7.5slave1 Ready 1m v1.7.5slave2 Ready 1m v1.7.5
可以看到,kubernetes集群已经部署成功,可以使用了。
参考资料
- Installing kubeadm,https://kubernetes.io/docs/setup/independent/install-kubeadm/
- 使用kubeadm在Red Hat 7/CentOS 7快速部署Kubernetes 1.7集群,http://dockone.io/article/2514
- CentOS7.3利用kubeadm安装kubernetes1.7.3完整版(官方文档填坑篇),https://www.cnblogs.com/liangDream/p/7358847.html
- How to execute “kubeadm init” v1.6.4 behind firewall,https://stackoverflow.com/questions/44432328/how-to-execute-kubeadm-init-v1-6-4-behind-firewall
- 使用 kubeadm 创建 kubernetes 1.9 集群,https://www.kubernetes.org.cn/3357.html
如有疑问,欢迎交流
原文地址:http://blog.51cto.com/11886896/2072527