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
# 将一个 Node 节点加入到当前集群中
$ kubeadm join <Master节点的IP和端口 >
1. 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或更多内存,2个CPU或更多CPU,硬盘30GB或更多
- 可以联网,需要拉取镜像,如果服务器不能上网,需要提前下载镜像并导入节点
2. 准备环境
角色 | IP |
master | 192.168.152.140 |
node1 | 192.168.152.141 |
node2 | 192.168.152.142 |
3台机器执行以下操作:
# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld
# 关闭selinux
sed -i 's/enforcing/disabled/' /etc/selinux/config # 永久
setenforce 0 # 临时
# 关闭swap
swapoff -a # 临时
sed -ri 's/.*swap.*/#&/' /etc/fstab # 永久
# 根据规划设置主机名
hostnamectl set-hostname <hostname>
# 如果终端上显示的主机名还是原来的,则关闭当前终端,另起一个终端即可。
# 配置主机名解析
cat >> /etc/hosts << EOF
192.168.152.140 master
192.168.152.141 node1
192.168.152.142 node2
EOF
# 将桥接的IPv4流量传递到iptables的链
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system # 生效
# 时间同步
yum install ntpdate -y
ntpdate time.windows.com
3. 所有节点安装Docker/kubeadm/kubelet
Kubernetes默认CRI(容器运行时)为Docker,因此先安装Docker。3台机器执行以下操作:
3.1 安装Docker
yum -y install yum-utils
yum-config-manager \
--add-repo \
https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
yum install -y docker-ce-18.09.3 docker-ce-cli-18.09.3 containerd.io
systemctl start docker
systemctl enable docker
$ cat > /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["https://9cpn8tt6.mirror.aliyuncs.com"]
}
EOF
#使配置文件生效
$ systemctl daemon-reload
#重启docker
$ systemctl restart docker
3.2 添加阿里云YUM软件源
3台机器执行以下操作:
$ cat > /etc/yum.repos.d/kubernetes.repo << EOF
[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
3.3 安装kubeadm,kubelet和kubectl
3台机器执行以下操作:
由于版本更新频繁,这里指定版本号部署(这里最好不要改版本,因为要注意与前面docker版本的兼容性,否则后续的 kubeadm init 会出问题):
$ yum install -y kubelet-1.18.0 kubeadm-1.18.0 kubectl-1.18.0
$ systemctl enable kubelet
4. 部署Kubernetes Master
在192.168.152.140(Master)执行:
$ kubeadm init \
--apiserver-advertise-address=192.168.152.140 \
--image-repository registry.aliyuncs.com/google_containers \
--kubernetes-version v1.18.0 \
--service-cidr=10.96.0.0/12 \
--pod-network-cidr=10.244.0.0/16
由于默认拉取镜像地址k8s.gcr.io国内无法访问,这里指定阿里云镜像仓库地址。
使用kubectl工具:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
$ kubectl get nodes
5. 加入Kubernetes Node
向集群添加新节点node1和node2,在node1,node2中执行在kubeadm init输出结果中的下面几行:
$ kubeadm join 192.168.152.140:6443 --token esce21.q6hetwm8si29qxwn \
--discovery-token-ca-cert-hash sha256:00603a05805807501d7181c3d60b478788408cfe6cedefedb1f97569708be9c5
默认token有效期为24小时,当过期之后,该token就不可用了。这时就需要重新创建token,操作如下:
$ kubeadm token create --print-join-command #将输出结果复制,在要加入的结点中粘贴执行
6. 部署CNI网络插件
以下操作只在master执行:
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
kube-flannel-ds-amd64-2pc95 1/1 Running 0 72s
如果以上kubectl apply命令连不上网,则可以用以下操作代替:
touch kube-flannel.yml #创建文件
vi kube-flannel.yml #编辑文件,内容如下
---
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
privilegedfalse
volumes
configMap
secret
emptyDir
hostPath
allowedHostPaths
pathPrefix"/etc/cni/net.d"
pathPrefix"/etc/kube-flannel"
pathPrefix"/run/flannel"
readOnlyRootFilesystemfalse
# Users and groups
runAsUser
rule RunAsAny
supplementalGroups
rule RunAsAny
fsGroup
rule RunAsAny
# Privilege Escalation
allowPrivilegeEscalationfalse
defaultAllowPrivilegeEscalationfalse
# Capabilities
allowedCapabilities'NET_ADMIN'
defaultAddCapabilities
requiredDropCapabilities
# Host namespaces
hostPIDfalse
hostIPCfalse
hostNetworktrue
hostPorts
min0
max65535
# SELinux
seLinux
# SELinux is unsed 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
{
"cniVersion": "0.2.0",
"name": "cbr0",
"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
hostNetworktrue
tolerations
operator Exists
effect NoSchedule
serviceAccountName flannel
initContainers
name install-cni
image lizhenliang/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 lizhenliang/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
privilegedfalse
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
kubectl apply -f kube-flannel.yml
kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
kube-flannel-ds-amd64-2pc95 1/1 Running 0 72s
7. 测试kubernetes集群
在master中执行:
在Kubernetes集群中创建一个pod,验证是否正常运行:
$ kubectl create deployment nginx --image=nginx
$ kubectl expose deployment nginx --port=80 --type=NodePort
$ kubectl get pod,svc
NAME READY STATUS RESTARTS AGE
pod/nginx-f89759699-lgg76 1/1 Running 0 2m34s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11m
service/nginx NodePort 10.106.148.244 <none> 80:31990/TCP 2m30s
使用浏览器访问:http://任意一个node结点访问的IP地址:31990
(31990对应上面输出结果中的那个端口号)