3.Kubernetes集群
Kubernetes用于协调高度可用的计算机集群,这些计算机群集被连接作为单个单元工作。Kubernetes 在一个集群
上以更有效的方式自动分发和调度容器应用程序。Kubernetes集群由两种类型的资源组成:
Master是集群的调度节点
Nodes是应用程序实际运行的工作节点
接下来为大家讲解一下如何快速部署一套Kubernetes集群,K8S集群部署有几种方式:kubeadm、minikube和二
进制包。前两者属于自动部署,简化部署操作,我们这里强烈推荐初学者使用二进制包部署,因为自动部署屏蔽了
很多细节,使得对各个模块感知很少,非常不利用学习。
3.1 环境准备与规划
推荐配置2核2G
Docker version 17.05.0-ce
查看默认防火墙状态(关闭后显示not running ,开启后显示 running)
firewall-cmd --state
关闭防火墙
systemctl stop firewalld.service
禁止firewall开机启动
systemctl disable firewalld.service
获取Kubernetes二进制包
https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.9.md
页面表格中找到Server Binaries中的kubernetes-server-linux-amd64.tar.gz文件,下载到本地。
该压缩包中包括了k8s需要运行的全部服务程序文件
3.2 Master安装
3.3.1 Docker安装
(1)设置yum源
vi /etc/yum.repos.d/docker.repo
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/$releasever/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
(2)安装docker
yum install docker-engine
(3)安装后查看docker版本
docker -v
3.3.2 etcd服务
etcd做为Kubernetes集群的主要服务,在安装Kubernetes各服务前需要首先安装和启动。
下载etcd二进制文件
https://github.com/etcd-io/etcd/releases
上传到master
可以使用lrzsz,如果没有安装,可以通过yum进行安装 yum install lrzsz
将将etcd和etcdctl文件复制到/usr/bin目录
配置systemd服务文件 /usr/lib/systemd/system/etcd.service
[Unit]
Description=Etcd Server
After=network.target
[Service]
Type=simple
EnvironmentFile=-/etc/etcd/etcd.conf
WorkingDirectory=/var/lib/etcd/
ExecStart=/usr/bin/etcd
Restart=on-failure
[Install]
WantedBy=multi-user.target
启动与测试etcd服务
systemctl daemon-reload
systemctl enable etcd.service
mkdir -p /var/lib/etcd/
systemctl start etcd.service
etcdctl cluster-health
3.3.3 kube-apiserver服务
解压后将kube-apiserver、kube-controller-manager、kube-scheduler以及管理要使用的kubectl二进制命令文件
放到/usr/bin目录,即完成这几个服务的安装。
cp kube-apiserver kube-controller-manager kube-scheduler kubectl /usr/bin/
下面是对kube-apiserver服务进行配置
编辑systemd服务文件 vi /usr/lib/systemd/system/kube-apiserver.service
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/kubernetes/kubernetes
After=etcd.service
Wants=etcd.service
[Service]
EnvironmentFile=/etc/kubernetes/apiserver
ExecStart=/usr/bin/kube-apiserver $KUBE_API_ARGS
Restart=on-failure
Type=notify
[Install]
WantedBy=multi-user.target
配置文件
创建目录:mkdir /etc/kubernetes
vi /etc/kubernetes/apiserver
KUBE_API_ARGS="--storage-backend=etcd3 --etcd-servers=http://127.0.0.1:2379
--insecure-bind-
address=0.0.0.0
--insecure-port=8080 --service-cluster-ip-range=169.169.0.0/16 --service-node-
port-range=1-65535 --admission-
control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ServiceAccount,Defaul
tStorageClass,ResourceQuota --logtostderr=true --log-dir=/var/log/kubernetes --v=2"
3.3.4 kube-controller-manager服务
kube-controller-manager服务依赖于kube-apiserver服务:
配置systemd服务文件:vi /usr/lib/systemd/system/kube-controller-manager.service
[Unit]
Description=Kubernetes Controller Manager
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=kube-apiserver.service
Requires=kube-apiserver.service
[Service]
EnvironmentFile=-/etc/kubernetes/controller-manager
ExecStart=/usr/bin/kube-controller-manager $KUBE_CONTROLLER_MANAGER_ARGS
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
配置文件 vi /etc/kubernetes/controller-manager
KUBE_CONTROLLER_MANAGER_ARGS="--master=http://193.168.126.140:8080 --logtostderr=true --log-
dir=/var/log/kubernetes --v=2"
3.3.5 kube-scheduler服务
kube-scheduler服务也依赖于kube-apiserver服务。
配置systemd服务文件:vi /usr/lib/systemd/system/kube-scheduler.service
[Unit]
Description=Kubernetes Scheduler
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=kube-apiserver.service
Requires=kube-apiserver.service
[Service]
EnvironmentFile=-/etc/kubernetes/scheduler
ExecStart=/usr/bin/kube-scheduler $KUBE_SCHEDULER_ARGS
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
配置文件:vi /etc/kubernetes/scheduler
KUBE_SCHEDULER_ARGS="--master=http://193.168.126.140:8080 --logtostderr=true --log-
dir=/var/log/kubernetes --v=2"
3.3.6 启动
完成以上配置后,按顺序启动服务
systemctl daemon-reload
systemctl enable kube-apiserver.service
systemctl start kube-apiserver.service
systemctl enable kube-controller-manager.service
systemctl start kube-controller-manager.service
systemctl enable kube-scheduler.service
systemctl start kube-scheduler.service
检查每个服务的健康状态:
systemctl status kube-apiserver.service
systemctl status kube-controller-manager.service
systemctl status kube-scheduler.service
3.3 Node1安装
在Node1节点上,以同样的方式把从压缩包中解压出的二进制文件kubelet kube-proxy放到/usr/bin目录中。
在Node1节点上需要预先安装docker,请参考Master上Docker的安装,并启动Docker
3.3.1 kubelet服务
配置systemd服务文件:vi /usr/lib/systemd/system/kubelet.service
[Unit]
Description=Kubernetes Kubelet Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=docker.service
Requires=docker.service
[Service]
WorkingDirectory=/var/lib/kubelet
EnvironmentFile=-/etc/kubernetes/kubelet
ExecStart=/usr/bin/kubelet $KUBELET_ARGS
Restart=on-failure
KillMode=process
[Install]
WantedBy=multi-user.target
mkdir -p /var/lib/kubelet
配置文件:vi /etc/kubernetes/kubelet
KUBELET_ARGS="--kubeconfig=/etc/kubernetes/kubeconfig --hostname-override=193.168.126.142 --
logtostderr=false --log-dir=/var/log/kubernetes --v=2 --fail-swap-on=false"
用于kubelet连接Master Apiserver的配置文件
vi /etc/kubernetes/kubeconfig
apiVersion: v1
kind: Config
clusters:
- cluster:
server: http://193.168.126.140:8080
name: local
contexts:
- context:
cluster: local
name: mycontext
current-context: mycontext
3.3.2 kube-proxy服务
kube-proxy服务依赖于network服务,所以一定要保证network服务正常,如果network服务启动失败,常见解决方
案有以下几中:
1.和 NetworkManager 服务有冲突,这个好解决,直接关闭 NetworkManger 服务就好了, service
NetworkManager stop,并且禁止开机启动 chkconfig NetworkManager off 。之后重启就好了
3.和配置文件的MAC地址不匹配,这个也好解决,使用ip addr(或ifconfig)查看mac地址,
将/etc/sysconfig/network-scripts/ifcfg-xxx中的HWADDR改为查看到的mac地址
3.设定开机启动一个名为NetworkManager-wait-online服务,命令为:
systemctl enable NetworkManager-wait-online.service
4.查看/etc/sysconfig/network-scripts下,将其余无关的网卡位置文件全删掉,避免不必要的影响,即只留一个以
ifcfg开头的文件
配置systemd服务文件:vi /usr/lib/systemd/system/kube-proxy.service
[Unit]
Description=Kubernetes Kube-proxy Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=network.service
Requires=network.service
[Service]
EnvironmentFile=/etc/kubernetes/proxy
ExecStart=/usr/bin/kube-proxy $KUBE_PROXY_ARGS
Restart=on-failure
LimitNOFILE=65536
KillMode=process
[Install]
WantedBy=multi-user.target
配置文件:vi /etc/kubernetes/proxy
KUBE_PROXY_ARGS="--master=http://193.168.126.140:8080 --hostname-override=193.168.126.142 --
logtostderr=true --log-dir=/var/log/kubernetes --v=2"
3.3.3 启动
systemctl daemon-reload
systemctl enable kubelet
systemctl start kubelet
systemctl status kubelet
systemctl enable kube-proxy
systemctl start kube-proxy
systemctl status kube-proxy
3.4 Node2安装
请参考Node1安装,注意修改IP
3.5 健康检查与示例测试
查看集群状态
查看master集群组件状态
nginx-rc.yaml
apiVersion: v1
kind: ReplicationController
metadata:
name: nginx
spec:
replicas: 3
selector:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
kubectl create -f nginx-rc.yaml
nginx-svc.yaml
apiVersion: v1
kind: Service
metadata:
name: nginx
spec:
type: NodePort
ports:
- port: 80
nodePort: 33333
selector:
app: nginx
kubectl create -f nginx-svc.yaml
查看pod
查看具体pod详情