使用kubeadm创建kubernets集群

参考:  http://docs.kubernetes.org.cn/459.html

     https://blog.csdn.net/gui951753/article/details/83316976#_1

     http://www.mamicode.com/info-detail-2544943.html

     https://blog.csdn.net/nklinsirui/article/details/80581286#debian-ubuntu

     https://cloud.tencent.com/info/852b3e3d1ad1bc020eaacd3bef724443.html

 

 

1. 规划

IP节点角色工作职责
172.10.30.100 master 对外暴露API,对内提供工作流的调度和配置
172.10.30.101 node1 承载着k8s运行的实际任务
172.10.30.102 node2 同node1相同

 

 

2. 部署前提

  • 主机名称解析,(在/etc/hosts文件编辑相关信息即可)

172.10.30.100 master

172.10.30.101 node1

172.10.30.102 node2

将上述配置文件拷贝到集群中的所有节点,包括master节点和node节点。

 

  •  时间同步(使用chrony服务实现)
yum -y install chrony 

vim /etc/chrony.conf

~~~
server master
#server 1.centos.pool.ntp.org iburst
#server 2.centos.pool.ntp.org iburst
#server 3.centos.pool.ntp.org iburst
~~~~
#注释掉原有的server内容,把原有的时钟同步服务设置为master结点上的时钟同步。
  • 关闭所有节点的iptables和firewalld以及selinux
iptables -F
systemctl stop firewalld
systemctl disable firewalld

sed -i '/^SELINUX=/s/SELINUX=.*/SELINUX=disabled/g' /etc/selinux/config
setenforce 0
 
  • 禁止iptables对bridge数据进行处理

cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF sysctl -p /etc/sysctl.conf # 不起作用
sysctl -p  /etc/sysctl.d/k8s.conf #这样可以
  • 关闭swap
swapoff -a 
sed 's/.*swap.*/#&/' /etc/fstab

 

 

 

3. docker 安装

参考: https://docs.docker.com/install/linux/docker-ce/centos/#uninstall-old-versions

这里安装特定的版本 docker-ce-18.06。

需要注意的是,Kubernetes 1.13已经针对Docker的1.11.1, 1.12.1, 1.13.1, 17.03, 17.06, 17.09, 18.06等版本做了验证,最低支持的Docker版本是1.11.1,最高支持是18.06,而Docker最新版本已经是18.09了,故我们安装时需要指定版本为18.06.1-ce

#移除旧版docker
yum
remove docker \ docker-client \ docker-client-latest \ docker-common \ docker-latest \ docker-latest-logrotate \ docker-logrotate \ docker-selinux \ docker-engine-selinux \ docker-engine #依赖 yum install -y yum-utils \ device-mapper-persistent-data \ lvm2 #docke-ce 官方yum 源 yum-config-manager \ --add-repo \ https://download.docker.com/linux/centos/docker-ce.repo

#阿里的docke-ce yum源 二者用其一
wget -P /etc/yum.repos.d/ https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo #从阿里云获取docker-ce的镜像文件,-P指定下载文件存放的目录
#查看docker版本 yum list docker-ce --showduplicates | sort -r
#安装
yum install docker-ce-18.06.1.ce-3.el7 -y


systemctl start docker

systemctl enable docker

 

4. kubectl、kubelete、kubeadm安装

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
setenforce 0
yum install -y kubelet kubeadm kubectl systemctl enable kubelet && systemctl start kubelet

 

5. 使用kubeadm创建一个单Master集群

5.1初始化Master节点

K8s的控制面板组件运行在Master节点上,包括etcd和API server(Kubectl便是通过API server与k8s通信)。

在执行初始化之前,我们还有一下3点需要注意:

1.选择一个网络插件,并检查它是否需要在初始化Master时指定一些参数,比如我们可能需要根据选择的插件来设置--pod-network-cidr参数。参考:Installing a pod network add-on

2.kubeadm使用eth0的默认网络接口(通常是内网IP)做为Master节点的advertise address,如果我们想使用不同的网络接口,可以使用--apiserver-advertise-address=<ip-address>参数来设置。如果适应IPv6,则必须使用IPv6d的地址,如:--apiserver-advertise-address=fd00::101

3.使用kubeadm config images pull来预先拉取初始化需要用到的镜像,用来检查是否能连接到Kubenetes的Registries。

Kubenetes默认Registries地址是k8s.gcr.io,很明显,在国内并不能访问gcr.io,因此在kubeadm v1.13之前的版本,安装起来非常麻烦,但是在1.13版本中终于解决了国内的痛点,其增加了一个--image-repository参数,默认值是k8s.gcr.io,我们将其指定为国内镜像地址:registry.aliyuncs.com/google_containers,其它的就可以完全按照官方文档来愉快的玩耍了。

其次,我们还需要指定--kubernetes-version参数,因为它的默认值是stable-1,会导致从https://dl.k8s.io/release/stable-1.txt下载最新的版本号,我们可以将其指定为固定版本(最新版:v1.13.0)来跳过网络请求。

现在,我们就来试一下:

# 使用calico网络 --pod-network-cidr=192.168.0.0/16
sudo kubeadm init --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.13.0 --pod-network-cidr=192.168.0.0/16

输出

[init] Using Kubernetes version: v1.13.0
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Activating the kubelet service
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [master localhost] and IPs [172.10.30.100 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [master localhost] and IPs [172.10.30.100 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [master kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local] and IPs [10.96.0.1 172.10.30.100]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 26.004391 seconds
[uploadconfig] storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.13" in namespace kube-system with the configuration for the kubelets in the cluster
[patchnode] Uploading the CRI Socket information "/var/run/dockershim.sock" to the Node API object "master" as an annotation
[mark-control-plane] Marking the node master as control-plane by adding the label "node-role.kubernetes.io/master=''"
[mark-control-plane] Marking the node master as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: 485yy9.azkhnftmz2mf9me5
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[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: CoreDNS
[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 172.10.30.100:6443 --token 485yy9.azkhnftmz2mf9me5 --discovery-token-ca-cert-hash sha256:165d19adeaac9bd84837367b414a45b01879dbb8f36092a32b957223904e9c30
输出

这次非常顺利的就部署成功了,如果我们想使用非root用户操作kubectl,可以使用以下命令,这也是kubeadm init输出的一部分:

 

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

 

5.2 安装网络插件

参考: https://kubernetes.io/docs/concepts/cluster-administration/addons/

            http://docs.kubernetes.org.cn/459.html

为了让Pods间可以相互通信,我们必须安装一个网络插件,并且必须在部署任何应用之前安装,CoreDNS也是在网络插件安装之后才会启动的。

网络的插件完整列表,请参考 Networking and Network Policy

在安装之前,我们先查看一下当前Pods的状态: 

[kuber@master ~]$ kubectl get pods --all-namespaces
NAMESPACE     NAME                             READY   STATUS    RESTARTS   AGE
kube-system   coredns-78d4cf999f-8z6d6         0/1     Pending   0          3m34s
kube-system   coredns-78d4cf999f-l4dhk         0/1     Pending   0          3m34s
kube-system   etcd-master                      1/1     Running   0          2m54s
kube-system   kube-apiserver-master            1/1     Running   0          2m43s
kube-system   kube-controller-manager-master   1/1     Running   0          2m50s
kube-system   kube-proxy-4jmf5                 1/1     Running   0          3m34s
kube-system   kube-scheduler-master            1/1     Running   0          2m35s

如上,可以看到CoreDND的状态是Pending,这是因为我们还没有安装网络插件。

Calico是一个纯三层的虚拟网络方案,Calico 为每个容器分配一个 IP,每个 host 都是 router,把不同 host 的容器连接起来。与 VxLAN 不同的是,Calico 不对数据包做额外封装,不需要 NAT 和端口映射,扩展性和性能都很好。

默认情况下,Calico网络插件使用的的网段是192.168.0.0/16,在init的时候,我们已经通过--pod-network-cidr=192.168.0.0/16来适配Calico,当然你也可以修改calico.yml文件来指定不同的网段。

可以使用如下命令命令来安装Canal插件:详细参考: https://docs.projectcalico.org/v3.4/getting-started/kubernetes/

#######
[kuber@master ~]$ cat /etc/NetworkManager/conf.d/calico.conf
[keyfile]
unmanaged-devices=interface-name:cali*;interface-name:tunl*



########
kubectl apply -f \
https://docs.projectcalico.org/v3.4/getting-started/kubernetes/installation/hosted/etcd.yaml


##########

kubectl apply -f \
https://docs.projectcalico.org/v3.4/getting-started/kubernetes/installation/hosted/calico.yaml

######
[kuber@master ~]$ kubectl get pods --all-namespaces
NAMESPACE     NAME                                       READY   STATUS    RESTARTS   AGE
kube-system   calico-etcd-7w8dl                          1/1     Running   0          24m
kube-system   calico-kube-controllers-5d94b577bb-kswkt   1/1     Running   0          37m
kube-system   calico-node-vl9cf                          1/1     Running   0          7m1s
kube-system   coredns-78d4cf999f-9cz26                   1/1     Running   4          40m
kube-system   coredns-78d4cf999f-stf4z                   1/1     Running   4          40m
kube-system   etcd-master                                1/1     Running   0          39m
kube-system   kube-apiserver-master                      1/1     Running   0          39m
kube-system   kube-controller-manager-master             1/1     Running   0          39m
kube-system   kube-proxy-snh7v                           1/1     Running   0          40m
kube-system   kube-scheduler-master                      1/1     Running   0          39m

如上,STATUS全部变为了Running,表示安装成功,接下来就可以加入其他节点以及部署应用了。

 

5.3  master隔离

默认情况下,由于安全原因,集群并不会将pods部署在Master节点上。但是在开发环境下,我们可能就只有一个Master节点,这时可以使用下面的命令来解除这个限制:

 

kubectl taint nodes --all node-role.kubernetes.io/master-

## 输出
node/master untainted

 

 5.4 加工作节点

要为群集添加工作节点,需要为每台计算机执行以下操作:

  • SSH到机器
  • 成为root用户,(如: sudo su -)
  • 运行上面的kubeadm init命令输出的:kubeadm join --token <token> <master-ip>:<master-port> --discovery-token-ca-cert-hash sha256:<hash>

如果我们忘记了Master节点的加入token,可以使用如下命令来查看:

kubeadm token list

# 输出
TOKEN                     TTL       EXPIRES                USAGES                   DESCRIPTION                                                EXTRA GROUPS
6pkrlg.8glf2fqpuf3i489m   22h       2018-12-07T13:46:33Z   authentication,signing   The default bootstrap token generated by 'kubeadm init'.   system:bootstrappers:kubeadm:default-node-token

默认情况下,token的有效期是24小时,如果我们的token已经过期的话,可以使用以下命令重新生成:

kubeadm token create

# 输出
u2mt59.tyqpo0v5wf05lx2q

如果我们也没有--discovery-token-ca-cert-hash的值,可以使用以下命令生成:

openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'

# 输出
eebfe256113bee397b218ba832f412273ae734bd4686241fb910885d26efd222

现在,我们登录到工作节点服务器,然后运行如下命令加入集群(这也是上面init输出的一部分):

kubeadm join 172.10.30.100:6443 --token 8gl99n.iu0m7c669vm0d1b1 --discovery-token-ca-cert-hash sha256:e3107f0be5fa44f939a6460b0c980a89e6d491dca89f5a44bc6923e40acc8e0b

 

 

等待一会,我们可以在Master节点上使用kubectl get nodes命令来查看节点的状态:

[kuber@master ~]$ kubectl get nodes
NAME     STATUS   ROLES    AGE   VERSION
master   Ready    master   50m   v1.13.1
node1    Ready    <none>   56s   v1.13.1

如上全部Ready,大功告成,我们可以运行一些命令来测试一下集群是否正常。

 

 

5.5 测试

首先验证kube-apiserverkube-controller-managerkube-schedulerpod network 是否正常:

# 部署一个 Nginx Deployment,包含两个Pod
# https://kubernetes.io/docs/concepts/workloads/controllers/deployment/
kubectl create deployment nginx --image=nginx:alpine
kubectl scale deployment nginx --replicas=2

# 验证Nginx Pod是否正确运行,并且会分配192.168.开头的集群IP
kubectl get pods -l app=nginx -o wide

# 输出如下:
NAME                     READY   STATUS    RESTARTS   AGE   IP            NODE    NOMINATED NODE   READINESS GATES
nginx-54458cd494-p8jzs   1/1     Running   0          31s   192.168.1.2   node1   <none>           <none>
nginx-54458cd494-v2m4b   1/1     Running   0          24s   192.168.1.3   node1   <none>           <none>

 

再验证一下kube-proxy是否正常:

# 以 NodePort 方式对外提供服务 https://kubernetes.io/docs/concepts/services-networking/connect-applications-service/
kubectl expose deployment nginx --port=80 --type=NodePort

# 查看集群外可访问的Port
kubectl get services nginx

# 输出
NAME    TYPE       CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
nginx   NodePort   10.110.49.49   <none>        80:31899/TCP   4s

# 可以通过任意 NodeIP:Port 在集群外部访问这个服务,本示例中部署的2台集群IP分别是172.17.20.210和172.17.20.211
curl http://172.17.20.210:31899
curl http://172.17.20.211:31899

 

最后验证一下dnspod network是否正常:

# 运行Busybox并进入交互模式
kubectl run -it curl --image=radial/busyboxplus:curl

# 输入`nslookup nginx`查看是否可以正确解析出集群内的IP,已验证DNS是否正常
[ root@curl-66959f6557-6sfqh:/ ]$ nslookup nginx

# 输出
Server:    10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local

Name:      nginx
Address 1: 10.110.49.49 nginx.default.svc.cluster.local

# 通过服务名进行访问,验证kube-proxy是否正常
[ root@curl-66959f6557-6sfqh:/ ]$ curl http://nginx/

# 输出如下:
# <!DOCTYPE html> ---省略

# 分别访问一下2个Pod的内网IP,验证跨Node的网络通信是否正常
[ root@curl-66959f6557-6sfqh:/ ]$ curl http://192.168.1.2/
[ root@curl-66959f6557-6sfqh:/ ]$ curl http://192.168.1.3/

 

posted @ 2018-12-19 14:51  你的泪我的眼  阅读(...)  评论(... 编辑 收藏