kubernetes集群类型
kubernetes集群大体上分为两类：一主多从和多主多从
- 一主多从：一台Master节点和多台Node节点，搭建简单，但有单机故障风险，适合于测试环境部署
- 多主多从：多台Matser节点和多台Node节点，搭建麻烦，安全性高，适用于生产环境
kubernetes安装方式
kuberbnetes有多种部署方式，目前主流的方式有kubeadm、minikube、二机制包
- kubeadm：一个快速搭建kubernetes集群的工具
- minikube：一个快速搭建单点kubernetes的工具
- 二进制包：从官网下载每个组件的二进制包，依次安装
kubenetes环境安装服务器配置
本人用的是真实的三台云服务器，不是虚拟机，使用虚拟机的话需要另行配置，如果服务器有docker且版本过高的话请卸载并安装稳定版本卸载docker
| 角色 | ip | 组件 |
| master | 123.249.4.17 | docker，kubectl，kubeadm，kubelet |
| Node1 | 120.46.9.98 | docker，kubectl，kubeadm，kubelet |
| Node2 | 120.46.51.145 | docker，kubectl，kubeadm，kubelet |
检查服务器版本
kubernetes安装对Centos版本有要求，要在7.5或以上
cat /etc/redhat-release
主机域名解析
vim /etc/hosts123.249.4.17 master
120.46.9.98 node1
120.46.51.145 node2
注意:最后一行留空格，否则可能不生效
时间同步
kubernetes要求集群中的时间节点必须精确一致，这里直接使用chronyd服务从网络获取时间
#启动chroynd服务
systemctl start chronyd
#设置choroynd开机自启动
systemctl enable chronyd
禁用iptables和firewalld服务
kubernetes和docker运行中会产生大量的iptables规则，为了避免系统规则跟他们混淆，直接关闭系统规则
#关闭firewalld服务
systemctl stop firewalld
systemctl disable firewalld
#关闭iptables服务
systemctl stop iptables
systemctl disable iptables
禁用selinux
selinux是linux系统下的一个安全服务，如果不关闭它，在安装集群的过程中会产生比较奇葩的问题
vim /etc/selinux/config
#修改值为disable
SETLINUX = disadble
#修改之后重启整个linux服务
禁用swap分区
swap分区指的是虚拟内存分区，它的作用是在物理内存使用完之后，将磁盘空间拟成内存来使用
启用swap分区会对系统的性能产生负面影响，因此kubernetes要求每个节点都要禁用swap设备，如果不能关闭分区，在集群安装过程中通过参数配置说明
vim /etc/fstab
注释掉分区中的swap分区内容，此操作也需要重启系统
修改linux内核参数
kubernetes的强制要求修改的内核参数
编辑/etc/sysctl.d/kubernetes.conf文件，无此文件，使用默认创建的新文件即可，添加如下配置：
vim /etc/sysctl.d/kubernetes.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
重新加载配置
sysctl -p
加载网桥过滤模块
modprobe br_netfilter
查看网桥过滤模块是否加载成功
lsmod | grep br_netfilter
配置ipvs功能
kubernetes中service有两种代理模型，一种基于iptables的，一种是基于ipvs的，两种比较的话，ipvs明显性能更高一些，但是如果要使用ipvs，需要手动载入
#安装ipset和ipvsadm
yum install ipset ipvsadm -y
#添加需要加载的模块写入脚本文件
cat <<EOF > /etc/sysconfig/modules/ipvs.modules
#! /bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF
#为脚本文件添加执行权限
chmod +x /etc/sysconfig/modules/ipvs.modules
#执行脚本文件
/bin/bash /etc/sysconfig/modules/ipvs.modules
#查看对应模块是否加载成功
lsmod ｜ grep -e ip_vs -e nf_conntrack_ipv4
至此，完成所有步骤之后，重启所有服务器
#重启服务器
reboot kubernetes环境安装
需要在每台服务器分别安装Docker（18.06.3.ce-3.el7） kubeadm、kubelet 、kubectl(v1.17.4)程序(无特殊强调都是在三台机器上共同操作)
安装Docker
#切换镜像源
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
#查看当前镜像源中支持的docker版本
yum list docker-ce --showduplicates
#安装特定版本的docker-ce 必须指定–setopt=obsoletes=0，否则yum会自动安装更高版本
yum install --setopt=obsoletes=0 docker-ce-18.06.3.ce-3.el7 -y
#如果最新版安装 yum install docker 正常安装到此结束即可
#添加一个配置文件，Docker在默认情况下使用的Cgroup Driver为cgroupfs，而kubernetes推荐使用#systemd来代替cgroupfs
mkdir /etc/docker
cat <<EOF > /etc/docker/daemon.json
{
"exec-opts" : ["native.cgroupdriver = systemd"],
"registry-mirrors" : ["https://qaisuteo.mirror.aliyuncs.com"]
}
EOF
#启动Docker
systemctl start docker
#设置开机自启动
systemctl enable docker
检查Docker是否正在使用systemd的cgroup驱动
docker info | grep Cgroup
安装kubernetes组件
#由于kubernetes的镜像源在国外，速度比较慢，这里切换成国内的镜像源
# 编辑/etc/yum.repos.d/kubernetes.repo，添加下面的配置
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=0
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
# 安装kubeadm、kubelet和kubectl
yum install --setopt=obsoletes=0 kubeadm-1.17.4-0 kubelet-1.17.4-0 kubectl-1.17.4-0 -y
# 配置kubelet的cgroup，编辑/etc/sysconfig/kubelet，添加下面的配置，里面有个空配置,删除即可
KUBELET_CGROUP_ARGS="--cgroup-driver=systemd"
KUBE_PROXY_MODE="ipvs"
#设置kubelet开机自启
systemctl enable kubelet
准备集群镜像
# 在安装kubernetes集群之前，必须要提前准备好集群需要的镜像，所需镜像可以通过下面命令查看
kubeadm config images list
# 下载镜像
# 此镜像在kubernetes的仓库中，由于网络原因，无法连接，下面提供了一种替换方案
images=(
kube-apiserver:v1.17.4
kube-controller-manager:v1.17.4
kube-scheduler:v1.17.4
kube-proxy:v1.17.4
pause:3.1
etcd:3.4.3-0
coredns:1.6.5
)
for imageName in ${images[@]};do
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName k8s.gcr.io/$imageName
docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
done
集群初始化
下面的操作只需要在master节点上执行，这里特别提示一下，如果是公有云，要写内网地址，不要写公网地址（大坑）
# 创建集群，注意将apiserver的ip地址换成自己的master地址
kubeadm init \
--kubernetes-version=v1.17.4 \
--pod-network-cidr=10.244.0.0/16 \
--service-cidr=10.96.0.0/12 \
--apiserver-advertise-address=192.168.0.12
复制下关键信息 ，按要求执行即可，不要复制下面的，复制集群创建成功提示的命令
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/
Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.0.12:6443 --token lkjig2.ti134s5qc59pypb2 \
--discovery-token-ca-cert-hash sha256:8693c29dda251a4f45306426178c90cae9294e19650dc7e1915564cebe80558d [root@ecs-601-0003 ~]# mkdir -p $HOME/.kube
[root@ecs-601-0003 ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@ecs-601-0003 ~]# sudo chown $(id -u):$(id -g) $HOME/.kube/config
如果要重新初始化
kubeadm reset
清理信息 之后再次进行初始化操作
cd ~ 进入根目录
ll -a 查看是否存在.kube文件
rm -rf /root/.kube
systemctl restart docker ## 重启docker
systemctl restart kubelet ## 重启kubelet
rm -rf /etc/cni/net.d
下面的操作只需要在node节点上执行
kubeadm join 192.168.0.12:6443 --token lkjig2.ti134s5qc59pypb2 \
--discovery-token-ca-cert-hash sha256:8693c29dda251a4f45306426178c90cae9294e19650dc7e1915564cebe80558d
在master上查看节点信息
安装网络插件
kubernetes支持多种网络插件，比如flannel、calico、canal等等，任选一种使用即可，本次选择flannel
只在master节点执行即可，插件使用的是DaemonSet的控制器，它会在每个节点上都运行
直接使用这个kube-flannel.yml ，https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml中的镜像地址是访问不到的
cat <<EOF > kube-flannel.yml
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
name: psp.flannel.unprivileged
annotations:
seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
privileged: false
volumes:
- configMap
- secret
- emptyDir
- hostPath
allowedHostPaths:
- pathPrefix: "/etc/cni/net.d"
- pathPrefix: "/etc/kube-flannel"
- pathPrefix: "/run/flannel"
readOnlyRootFilesystem: false
# Users and groups
runAsUser:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
fsGroup:
rule: RunAsAny
# Privilege Escalation
allowPrivilegeEscalation: false
defaultAllowPrivilegeEscalation: false
# Capabilities
allowedCapabilities: ['NET_ADMIN']
defaultAddCapabilities: []
requiredDropCapabilities: []
# Host namespaces
hostPID: false
hostIPC: false
hostNetwork: true
hostPorts:
- min: 0
max: 65535
# SELinux
seLinux:
# SELinux is unused in CaaSP
rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: flannel
rules:
- apiGroups: ['extensions']
resources: ['podsecuritypolicies']
verbs: ['use']
resourceNames: ['psp.flannel.unprivileged']
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: flannel
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: kube-flannel-cfg
namespace: kube-system
labels:
tier: node
app: flannel
data:
cni-conf.json: |
{
"name": "cbr0",
"cniVersion": "0.3.1",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
},
{
"type": "portmap",
"capabilities": {
"portMappings": true
}
}
]
}
net-conf.json: |
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "vxlan"
}
}
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-amd64
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- amd64
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-amd64
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-amd64
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-arm64
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- arm64
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-arm64
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-arm64
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-arm
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- arm
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-arm
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-arm
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-ppc64le
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- ppc64le
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-ppc64le
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-ppc64le
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds-s390x
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: beta.kubernetes.io/os
operator: In
values:
- linux
- key: beta.kubernetes.io/arch
operator: In
values:
- s390x
hostNetwork: true
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.11.0-s390x
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-s390x
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg
EOF
kubectl apply -f kube-flannel.yml
#查看状态
kubectl get pod -n kube-system
#如果不行可以卸载flannel
kubectl delete -f kube-flannel.yml
kubectl get nodes
如果出现 coredns模块一直处于pending状态，需要下载包解压到/opt/cni/bin目录，所有节点都要操作https://github.com/containernetworking/plugins/releases/download/v0.8.6/cni-plugins-linux-amd64-v0.8.6.tgz
tar zxvf cni-plugins-linux-amd64-v0.8.6.tgz -C /opt/cni/bi
再次查看节点状态
节点显示none，重新命名一下
kubectl label node <nodename> node-role.kubernetes.io/worker=worker
至此，集群搭建完毕，过程中有许多的坑和注意事项，每个版本之间也可能会有差异，如果要是离线搭建的话就更费劲了
在node节点使用kubectl命令
kubectl 命令在master节点好用，那么在node节点也是可以使用的，现在在node节点使用是这样的
原因就是kubectl的运行是需要进行配置的，它的配置文件是$HOME/.kube，如果想要在node节点运行此命令，需要将master上的.kube文件复制到node节点上才可以执行
scp -r HOME/.kube node1: HOME/测试kubernetes集群
在k8s集群中部署一个nginx服务，并外网访问。
# 1.部署nginx
kubectl create deployment nginx --image=nginx:1.18.0
# 2.暴露端口
kubectl expose deployment nginx --port=80 --type=NodePort
# 3.查看服务状态
kubectl get pods,service | kubectl get pods,svc
30171就是暴露出来对外访问端口，访问试一下
