k8s基本概念
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RAM，2个CPU或更多CPU，硬盘30GB或更多
- 可以访问外网，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
- 禁止swap分区
2. 准备环境
| 角色 | IP |
|---|---|
| master | 10.0.0.200 |
| node1 | 10.0.0.201 |
| node2 | 10.0.0.202 |
# 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
# master
hostnamectl set-hostname master
# node1
hostnamectl set-hostname node1
# node2
hostnamectl set-hostname node2
# 在master添加hosts
cat >> /etc/hosts << EOF
10.0.0.200 master
10.0.0.201 node1
10.0.0.202 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。
3.1 安装Docker
yum install -y wget
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
yum -y install docker
systemctl enable docker && systemctl start docker
$ cat > /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF
3.2 添加阿里云YUM软件源
$ 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
由于版本更新频繁，这里可以指定版本号部署：
# 指定版本号，若不指定为latest
# yum install -y kubelet-1.16.3 kubeadm-1.16.3 kubectl-1.16.3
yum install -y kubelet kubeadm kubectl
systemctl enable kubelet && systemctl start kubelet
4. 部署Kubernetes Master
在Master执行。
kubeadm init --apiserver-advertise-address=10.0.0.200 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.20.4 --service-cidr=10.96.0.0/12 --pod-network-cidr=10.244.0.0/16
# --apiserver-advertise-address API服务器所公布的其正在监听的IP地址
# --image-repository 选择用于拉取控制平面镜像的容器仓库，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。
# --kubernetes-version 如果上方安装kubelet没有指定版本号，这里也可不指定，需要注意不同版本之间的兼容，不兼容会有报错，指定兼容版本即可。
# --service-cidr 为服务的虚拟 IP 地址另外指定 IP 地址段
# --pod-network-cidr 指明 pod 网络可以使用的 IP 地址段。
如果提示找不到coredns:v1.8.0，就先在kubeadm init后加 --ignore-preflight-errors=all忽略报错。kubeadm init结束后，继续后面的步骤。
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
在Node执行。
向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：
$ kubeadm join 192.168.1.11:6443 --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
6. 部署CNI网络插件
vi 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 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
hostNetwork: true
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:
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
kubectl apply -f kube-flannel.yml
kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-7f89b7bc75-5bk98 1/1 Running 0 22m
coredns-7f89b7bc75-cz8vq 1/1 Running 0 22m
etcd-master 1/1 Running 0 22m
kube-apiserver-master 1/1 Running 0 22m
kube-controller-manager-master 1/1 Running 0 22m
kube-flannel-ds-amd64-2cpdk 1/1 Running 0 7m3s
kube-flannel-ds-amd64-4xntj 1/1 Running 0 7m3s
kube-flannel-ds-amd64-khqfw 1/1 Running 0 7m3s
kube-proxy-7rc7h 1/1 Running 0 22m
kube-proxy-fncg8 1/1 Running 0 16m
kube-proxy-rd6kl 1/1 Running 0 16m
kube-scheduler-master 1/1 Running 0 22m
kubectl get pod -n kube-system -o wide
在kubectl get pods -n kube-system，如果发现有ImagePullBackOff或者ErrImagePull，例如coredns-545d6fc579-4jw9w镜像是ImagePullBackOff状态，那么执行
kubectl get pods coredns-545d6fc579-4jw9w -n kube-system -o yaml | grep image:
查看没有拉去下来的镜像的全称，例如：
registry.aliyuncs.com/google_containers/coredns/coredns:v1.8.0无法下载下来，然后手动docker pull拉取下来(有时候只是镜像的命名问题而提示找不到镜像)：docker pull coredns/coredns:1.8.0，然后手动将拉去下来的镜像改以下tag:
sudo docker tag coredns/coredns:1.8.0 registry.aliyuncs.com/google_containers/coredns/coredns:v1.8.0
7. 测试kubernetes集群
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
访问地址：http://NodeIP:Port
8. 安装dashboard
-
下载yaml
wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.4/aio/deploy/recommended.yaml
关于raw.githubusercontent.com failed: Connection -
修改yaml
-
执行安装
kubectl apply -f recommended.yaml -
创建 serviceaccount
kubectl create serviceaccount dashboard-admin -n kube-system -
创建clusterrolebinding为dashboard sa授权集群权限cluster-admin
kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin -
查看dashboard所在node 可以用
kubectl get pods -A -o wide,然后找到dashboard 所在的node节点.
使用token 登陆,获取token:kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')
关于dashboard的pod一直处于pending状态：
kubectl delete -f recommended.yaml
vi recommended.yaml
将所有
nodeSelector:
"kubernetes.io/os": linux
注释掉
kubectl apply -f recommended.yaml
为匿名用户绑定管理员权限
kubectl create clusterrolebinding test:anonymous --clusterrole=cluster-admin --user=system:anonymous
