1 前置知识点
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Mater节点和多台Node节点，搭建简单，但是由单机故障风险，适合用于测试环境
- 多主多从：多台Master节点和多台Node节点，搭建麻烦，安全性高，适用于生产环境。
1.2 安装方式
Kubernetes 多有多种部署方式，目前主流的方式由kubeadm、minikube、二进制包
- minikube：一个用于快速搭建单节点kubernetes的工具
- kubeadm：一个用快速搭建kubernetes集群的工具
- 二进制包：从官网下载每个组件的二进制包，以此去安装，此方式对于理解 kubernetes 组件更加有效
新手推荐 kubeadm
1.3 kubeadm 部署方式介绍
kubeadm 是官方社区推出的一个用于快速部署 kubernetes 集群的工具，这个工具能通过两条指令完成一个 kubernetes 集群的部署：
- 创建一个Master 节点 kubeadm init
- 将Node 节点加入到当前集群中$ kubeadm join <Master 节点的IP 和端口>
kubeadm 安装集群要求 centos7.5 及以上
1.4 安装要求
在开始之前，部署Kubernetes 集群机器需要满足以下几个条件：
- 一台或多台机器，操作系统CentOS7.x-86_x64
- 硬件配置：2GB 或更多RAM，2 个CPU 或更多CPU，硬盘30GB 或更多
- 集群中所有机器之间网络互通
- 可以访问外网，需要拉取镜像
- 禁止swap 分区
1.5 最终目标
- 在所有节点上安装 Docker 和 kubeadm
- 部署 Kubernetes Master
- 部署容器网络插件
- 部署 Kubernetes Node，将节点加入 Kubernetes 集群中
- 部署 Dashboard Web 页面，可视化查看 Kubernetes 资源
2 安装部署
| 角色 | hostname | ip | 组件 |
|---|---|---|---|
| master | node101 | 192.168.81.101 | docker，kubectl，kubeadm，kubelet |
| node1 | node102 | 192.168.81.102 | docker，kubectl，kubeadm，kubelet |
| node2 | node103 | 192.168.81.103 | docker，kubectl，kubeadm，kubelet |
以下没有特定说明在 Master 还是 Node 上操作，默认全部节点需要操作。
2.1 hostname及解析
不管搭建设什么集群，切记设置好 hostname，比较方便。两个步骤完成设置：
- 临时设置。hostname 节点名称
- vim /etc/hostname
设置完成后要添加解析 hostname 主机名的IP映射，vim /etc/hosts 直接修改
192.168.81.101 node101
192.168.81.102 node102
192.168.81.103 node103
hostname node101
vim /etc/hostname
node101
2.2 时间同步
Kubernetes 要求据群众的节点时间必须精确一致，这里直接使用chronyd服务从网络同步时间。企业中建议配置内部的时间同步服务器。
# 启动chronyd服务
systemctl start chronyd
# 设置chronyd服务开机自启动
systemctl enable chronyd
# chronyd 服务启动稍等几秒钟，就可以使用data命令验证时间了
date
2.3 禁用iptables 和 firewalld 服务
Kubernetes 和 docker 在运行中会产生大量的 iptables 规则，为了不让系统规则跟他们混淆，直接关闭系统的规则，生产系统建议开启，需要开放哪些端口或者IP，手动配置。
# 关闭 firewalld 服务
systemctl stop firewalld
systemctl disable firewalld
# 关闭iptanles服务
systemctl stop iptables
systemctl disable iptables
2.4 禁用 selinux
selinux 是 linux 系统下的一个安全服务，如果不关闭它，在安装集群中可能会被限制
# 临时关闭
setenforce 0
# 永久禁用
vim /etc/selinux/config
SELINUX=disabled
2.5 禁swap用分区
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，将磁盘空间虚拟成内存来使用，启用swap设备会对系统的性能产生非常负面的影响，因此 Kubernetes 要求每个节点都要禁用swap设备，但是如果因为某些原因确实不能关闭swap分区，就需要在集群安装的过程中通过明确的参数进行配置说明。
# 临时关闭
swapoff -a
# 永久关闭，编辑分区配置文件 /etc/fstab，注释掉 wap 分区一行
#/dev/mapper/centos-swap swap swap defaults 0 0
2.6 修改linxu的内核参数
# 修改linux的内核参数，添加网桥过滤和地址转发功能
# 编辑 /etc/sysctl.d/k8s.conf 文件，添加如下配置：
net.bridge.bridge-nf-call-iptables=1
net.bridge.bridge-nf-call-ip6tables=1
net.ipv4.ip_forward=1
net.ipv4.tcp_tw_recycle=0
vm.swappiness=0
vm.overcommit_memory=1
vm.panic_on_oom=0
fs.inotify.max_user_watches=89100
fs.file-max=52706963
fs.nr_open=52706963
net.ipv6.conf.all.disable_ipv6=1
net.netfilter.nf_conntrack_max=2310720
# 加载网桥过滤模块
modprobe br_netfilter
modprobe ip_conntrack
# 配置完成后重新加载配置文件
sysctl -p /etc/sysctl.d/k8s.conf
# 查看网桥过滤模块是否添加成功
lsmod | grep br_netfilter
2.7 配置 ipvs
在 Kubernetes 中 service 有两种代理模型，一种是基于 iptables 的，一种是基于 ipvs的，两者比较的话，ipvs 的性能明显更要高一些，但是如果要使用它，需要手动载入 ipvs 模块
# 安装 ipset 和 ipvsadm
yum install ipset ipvsadm -y
# 添加需要加载得模块写入脚本文件
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
modprobe -- br_netfilter
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
# 查看对应得模块是否加载成功
lsmod | grep -e ip_vs -e nf_conntrack_ipv4
2.8 docker 安装
# 之前安装过docker 卸载
yum remove docker-*
# 更换镜像地址
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
# 检查支持版本
yum list docker-ce --showduplicates | sort -r
# 安装
yum install --setopt=obsoletes=0 docker-ce-18.06.3.ce-3.el7
# 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
cat > /etc/docker/daemon.json <<EOF
{
"registry-mirrors": ["https://bk6kzfqm.mirror.aliyuncs.com"],
"data-root": "/data/docker",
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2",
"storage-opts": [
"overlay2.override_kernel_check=true"
]
}
EOF
# 启动docker
systemctl restart docker
systemctl enable docker
#检查版本
docker version
2.9 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
# 添加配置文件
vim /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
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
设置kubelet开机自启动
systemctl enable kubelet
2.10 集群初始化
准备镜像
kubeadm config images list
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
初始化
在 Master 点操作如下
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=10.240.30.113
- kubernetes-version 为版本
- pod-network-cidr 指定 pod 网络
- service-cidr 指定 service 网络
- apiserver-advertise-address 指定 master 的 IP 地址
- image-repository registry.aliyuncs.com/google_containers 指定镜像源为阿里，前面已经拉取过镜像了，所以不需要在拉
# 安装过程中报错如果报错，查看日志
journalctl -xfeu kubelet
# 重置 kubeadm 的信息
kubeadm reset
在 Master 点创建必要的文件，是 kubectl 以后要执行的配置文件
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
其他子节点执行，安装成功后会有信息告诉你
kubeadm join 192.168.81.101:6443 --token d5ejth.9s60snjt5xlh9lnt \
--discovery-token-ca-cert-hash sha256:04aab4993001f66f607e959b120294eddcc8579a5ea7d7364f48d84caecc90c9
查看所有节点
kubectl get nodes
2.11 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
master 操作
创建文件，复制执内容到文件中
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
执行以下命令
kubectl apply -f kube-flannel.yml
查看节点状态，只要从 NotReady 到 Ready 就算成功
服务部署
部署一个nginx程序，测试下集群是否在正常工作，直接在master操作
# 部署nginx
kubectl create deployment nginx --image=nginx:1.14-alpine
# 暴露端口
kubectl expose deployment nginx --port=80 --type=NodePort
# 查看服务状态
[root@localhost package]# kubectl get pods,svc
NAME READY STATUS RESTARTS AGE
pod/nginx-6867cdf567-2l7tr 1/1 Running 0 50s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 71m
service/nginx NodePort 10.101.119.180 <none> 80:31543/TCP 35s
31543 这个端口就是外部端口，可以通过节点名称+端口号直接访问测试
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