文章目录
K8s集群部署
一、初始化集群
1.在master节点进行初始化操作
Kubernetes 1.8开始要求关闭系统的Swap，如果不关闭，默认配置下kubelet将无法启动，关闭系统的Swap方法如下:
swapoff -a
开始初始化
kubeadm init --kubernetes-version=v1.20.4 --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=自己IP --ignore-preflight-errors=Swap
如显示以下消息则成功完成初始化
并 复制以下内容
[addons] Applied essential addon: kube-proxy
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 10.9.29.106:6443 --token x8awau.rxteung7iir394e8 \
--discovery-token-ca-cert-hash sha256:273528cee3b448a4c92394b0844021ea2514c1c895742ca5835f35d3fecac494
其中有以下关键内容：
[kubelet]生成kubelet的配置文件”/var/lib/kubelet/config.yaml”
[certificates]生成相关的各种证书
[kubeconfig]生成相关的kubeconfig文件
[bootstraptoken]生成token记录下来，后边使用kubeadm join往集群中添加节点时会用到
2.在master节点配置使用kubectl
依据复制内容的提示进行配置
假如你希望用一个普通用户运行集群，执行如下操作
rm -rf $HOME/.kube
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
假如你使用 root 用户运行集群，执行如下命令
export KUBECONFIG=/etc/kubernetes/admin.conf
3.查看当前node节点
kubectl get nodes
二、配置网路插件
1.master节点下载yaml配置文件
cd ~ && mkdir flannel && cd flannel
wget https://github.com/flannel-io/flannel/blob/master/Documentation/kube-flannel.yml
需要修改自己的网卡，有多少写多少
注意是 ens33 或者 eth0
[root@k8s-master flannel]# cat 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', '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: quay.io/coreos/flannel:v0.13.1-rc2
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:v0.13.1-rc2
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
- --iface=ens33 #在我这里修改
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-cf
2.启动
kubectl apply -f ~/flannel/kube-flannel.yml
3.查看
[root@k8s-master flannel]# kubectl get pods --namespace kube-system
NAME READY STATUS RESTARTS AGE
coredns-74ff55c5b-cjc8x 1/1 Running 0 20m
coredns-74ff55c5b-stf4z 1/1 Running 0 20m
etcd-k8s-master 1/1 Running 0 20m
kube-apiserver-k8s-master 1/1 Running 0 20m
kube-controller-manager-k8s-master 1/1 Running 0 20m
kube-flannel-ds-2m646 1/1 Running 0 76s
kube-proxy-4qqqr 1/1 Running 0 20m
kube-scheduler-k8s-master 1/1 Running 0 20m
[root@k8s-master flannel]# kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 20m
[root@k8s-master flannel]# kubectl get svc --namespace kube-system
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP,9153/TCP 20m
[root@k8s-master flannel]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master Ready control-plane,master 20m v1.20.4
只有网络插件也安装配置完成之后，才能会显示为ready状态
三、配置所有node节点加入集群
在所有node节点操作，此命令为初始化master成功后返回的结果
注意是在node节点
之前复制的 token在这里使用
swapoff -a
kubeadm join 10.9.29.106:6443 --token x8awau.rxteung7iir394e8 \
--discovery-token-ca-cert-hash sha256:273528cee3b448a4c92394b0844021ea2514c1c895742ca5835f35d3fecac494
四、集群检测
节点加入到集群之后再次查看
[root@k8s-master flannel]# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-74ff55c5b-cjc8x 1/1 Running 0 31m
coredns-74ff55c5b-stf4z 1/1 Running 0 31m
etcd-k8s-master 1/1 Running 0 31m
kube-apiserver-k8s-master 1/1 Running 0 31m
kube-controller-manager-k8s-master 1/1 Running 0 31m
kube-flannel-ds-2m646 1/1 Running 0 12m *
kube-proxy-4qqqr 1/1 Running 0 31m
kube-scheduler-k8s-master 1/1 Running 0 31m
[*]遇到异常状态0/1的pod长时间启动不了可删除它等待集群创建新的pod资源
kubectl delete pod kube-flannel-ds-sr6tq -n kube-system
pod "kube-flannel-ds-sr6tq" deleted
删除后，稍等片刻再次查看，发现状态为正常
[root@k8s-master flannel]# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-74ff55c5b-cjc8x 1/1 Running 0 45m
coredns-74ff55c5b-stf4z 1/1 Running 0 45m
etcd-k8s-master 1/1 Running 0 45m
kube-apiserver-k8s-master 1/1 Running 0 45m
kube-controller-manager-k8s-master 1/1 Running 0 45m
kube-flannel-ds-2m646 1/1 Running 0 26m
kube-flannel-ds-79vfz 1/1 Running 0 2m37s
kube-flannel-ds-wm7bc 1/1 Running 0 2m39s
kube-proxy-4qqqr 1/1 Running 0 45m
kube-proxy-b57j7 1/1 Running 0 2m39s
kube-proxy-k2w67 1/1 Running 0 2m37s
kube-scheduler-k8s-master 1/1 Running 0 45m
[root@k8s-master flannel]# kubectl get nodes -n kube-system
NAME STATUS ROLES AGE VERSION
k8s-master Ready control-plane,master 45m v1.20.4
k8s-node1 Ready <none> 2m40s v1.20.4
k8s-node2 Ready <none> 2m42s v1.20.4
1.清理集群
删除对集群的本地引用
kubectl config delete-cluster
删除节点
使用适当的凭证与控制平面节点通信，运行：
kubectl drain <node name> --delete-local-data --force --ignore-daemonsets
[*]在删除节点之前，请重置 kubeadm 安装的状态：
kubeadm reset
重置过程不会重置或清除 iptables 规则或 IPVS 表。如果你希望重置 iptables，则必须手动进行：
iptables -F && iptables -t nat -F && iptables -t mangle -F && iptables -X
如果要重置 IPVS 表，则必须运行以下命令：
ipvsadm -C
现在删除节点：
kubectl delete node <node name>
如果你想重新开始，只需运行 kubeadm init 或 kubeadm join 并加上适当的参数。
清理控制平面
你可以在控制平面主机上使用 kubeadm reset 来触发尽力而为的清理。
有关此子命令及其选项的更多信息，请参见 [ kubeadm reset ] 参考文档。
五、使用 kubernetes 工作
1.编写yaml文件
k8s推荐使用配置文件运行一个或者多个容器
配置文件可以是 yaml格式或者json文件
这里以运行nginx容器 为例
nginx.tml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
spec:
selector:
matchLabels:
app: nginx
replicas: 2
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.8
ports:
- containerPort: 80
2.运行 yaml 文件
kubectl apply -f nginx.yml
3.获取 pods 列表
运行此容器的节点会先下载容器的镜像，因此不一定会立刻就绪
kubectl get pods -l app=nginx
[root@k8s-master yaml]# kubectl get pods -l app=nginx
NAME READY STATUS RESTARTS AGE
nginx-deployment-64c9d67564-847kn 0/1 ContainerCreating 0 16s
nginx-deployment-64c9d67564-k5sjf 0/1 ContainerCreating 0 16s
4.查看某个 POD 的事件信息
kubectl describe pods 你的nginx名字
kubectl describe pods nginx-deployment-64c9d67564-k5sjf
下面的内容最后一行的 Pulling image 表示容器使用的镜像正在下载。
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 75s default-scheduler Successfully assigned default/nginx-deployment-64c9d67564-847kn to k8s-node1
Normal Pulling 67s kubelet Pulling image "nginx:1.8"
从上面的事件信息中的第一行可以看出此容器运行于哪个节点。
下面的内容表示容器已经成功运行了
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 46m default-scheduler Successfully assigned default/nginx-deployment-64c9d67564-847kn to k8s-node1
Normal Pulling 45m kubelet Pulling image "nginx:1.8"
Normal Pulled 43m kubelet Successfully pulled image "nginx:1.8" in 2m15.560747316s
Normal Created 43m kubelet Created container nginx
Normal Started 43m kubelet Started container nginx
六、kubernetes API 对象的滚动更新
1 修改之前的 YAML 文件
修改nginx.yml文件中的 image: 部分的值：
由原来的
image: nginx:1.8
修改为
image: nginx:1.9
之后执行如下命令进行生效
kubectl apply -f nginx.yml
在接下来的几分钟时间内，可以间歇性的反复使用如下命令来观察整个更新的过程（被调度的节点会依次执行下载镜像，运行容器的动作）。
kubectl get pods
kubectl describe pods
通过上面的更新示例，相信你可以体会到:
Kubernetes 会根据 YAML 文件的内容变化，自动进行具体的处理。
七、删除对象
kubectl delete -f nginx.yml
八、k8s 命令补全
k8s命令补全 官方文档
yum install bash-completion
echo 'source <(kubectl completion bash)' >>~/.bashr
版权声明：本文为Houaki原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接和本声明。