环境
- virtual box 6.1
- centos 7.8
- docker 19.03
- kubernetes 1.20.2
安装必备软件
添加 Kubernetes 仓库
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=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
安装软件
yum install -y kubelet kubeadm kubectl
systemctl enable kubelet && systemctl start kubelet
kubeadm 创建集群
初始化主节点
kubeadm init --image-repository registry.aliyuncs.com/google_containers --apiserver-advertise-address 192.168.56.101 --pod-network-cidr 10.244.0.0/16
--pod-network-cidr 10.244.0.0/16 是后面 flannel 网络插件默认值。
最终会看到输出如下的内容：
Your Kubernetes control-plane has initialized successfully!
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
Alternatively, if you are the root user, you can run:
export KUBECONFIG=/etc/kubernetes/admin.conf
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 192.168.56.101:6443 --token ir22ai.to5rqixx90mscp4i --discovery-token-ca-cert-hash sha256:efe632e2b03d00b873b888702882d8127f83540677034a0226cec599cd139050
配置 kubectl
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
查看节点状态
[root@master ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master NotReady control-plane,master 2m v1.20.2
安装 flannel 插件
[root@master ~]# kubectl apply -f kube-flannel-aliyun.yml
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
flannel.yml 的内容见附录。
加入工作节点
以下命令根据 kubeadm init 的最终输出来，拷贝最后两行的 kubeadm join 命令。
[root@node1 ~]# kubeadm join 192.168.56.101:6443 --token ir22ai.to5rqixx90mscp4i > --discovery-token-ca-cert-hash sha256:efe632e2b03d00b873b888702882d8127f83540677034a0226cec599cd139050
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with ‘kubectl -n kube-system get cm kubeadm-config -o yaml‘
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run ‘kubectl get nodes‘ on the control-plane to see this node join the cluster.
再次查看节点状态
[root@master ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master Ready control-plane,master 9m23s v1.20.2
node1 Ready <none> 78s v1.20.2
node2 Ready <none> 68s v1.20.2
查看 POD 状态
[root@master ~]# kubectl get pod --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system coredns-7f89b7bc75-9mff4 1/1 Running 0 9m43s
kube-system coredns-7f89b7bc75-9qvqx 1/1 Running 0 9m43s
kube-system etcd-master 1/1 Running 0 9m52s
kube-system kube-apiserver-master 1/1 Running 0 9m52s
kube-system kube-controller-manager-master 1/1 Running 0 9m52s
kube-system kube-flannel-ds-jjldk 1/1 Running 0 105s
kube-system kube-flannel-ds-rjqln 1/1 Running 0 115s
kube-system kube-flannel-ds-zp5xn 1/1 Running 0 4m42s
kube-system kube-proxy-bs7ft 1/1 Running 0 115s
kube-system kube-proxy-g67nx 1/1 Running 0 9m43s
kube-system kube-proxy-w99js 1/1 Running 0 105s
kube-system kube-scheduler-master 1/1 Running 0 9m52s
如果在安装的过程中出现了问题，可以使用 kubeadm reset 命令还原状态。
kubectl 命令提示
yum install bash-completion
kubectl completion bash >/etc/bash_completion.d/kubectl
总结
介绍了使用 kubeadm 安装 Kubernetes 的方式。
附录
flannel.yml 内容
---
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‘, ‘NET_RAW‘]
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/v1
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/v1
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
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: kubernetes.io/os
operator: In
values:
- linux
hostNetwork: true
priorityClassName: system-node-critical
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: easzlab/flannel:v0.13.0-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: easzlab/flannel:v0.13.0-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", "NET_RAW"]
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