Kubernetes学习目录
1、初始化Master
1.1、初始化命令
kubeadm init --kubernetes-version=1.25.7 \
--apiserver-advertise-address=192.168.10.26 \
--service-cidr=10.96.0.0/12 \
--pod-network-cidr=10.244.0.0/16 \
--image-repository=registry.aliyuncs.com/google_containers \
--ignore-preflight-errors=Swap
注意：
--apiserver-advertise-address 要设定为当前集群的master地址由于kubeadm init命令默认去外网获取镜像，这里我们使用--image-repository来指定使用国内镜像
--kubernetes-version选项的版本号用于指定要部署的Kubenretes程序版本，它需要与当前的kubeadm支持的版本保持一致；该参数是必须的
--pod-network-cidr选项用于指定分Pod分配使用的网络地址，它通常应该与要部署使用的网络插件（例如flannel、calico等）的默认设定保持一致，10.244.0.0/16是flannel默认使用的网络；
--service-cidr用于指定为Service分配使用的网络地址，它由kubernetes管理，默认即为10.96.0.0/12；
--ignore-preflight-errors=Swap 如果没有该项，必须保证系统禁用Swap设备的状态。一般最好加上
--image-repository 用于指定我们在安装kubernetes环境的时候，从哪个镜像里面下载相关的docker镜像，如果需要用本地的仓库，那么就用本地的仓库地址即可如：
--image-repository 10.0.0.19:80/google_containers ，因为提前下载，打标签为默认，所以这里不用配置
1.2、初始化成功的打印日志的介绍
# 运行成功，显示如下
Your Kubernetes control-plane has initialized successfully!
# 配置kubectl可以访问的方法
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:
# 加入集群的方法
kubeadm join 192.168.10.26:6443 --token chsuee.cxw3s9mdyodk8ehk \
--discovery-token-ca-cert-hash sha256:5cd4bd62fa2c5bd83eb50c40dd941d3fdcd31edc9b7a169d3442ee2da6363218
1.3、配置kubectl可访问apiserver
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
[root@master1 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master1 NotReady control-plane 5m15s v1.26.2
2、集群的重置
如果因为特殊因素导致，集群创建失败，我们可以通过两条命令实现环境的快速还原
2.1、Master重置清空方法
# Master节点重置
kubeadm reset;
rm -rf /etc/kubernetes;
rm -rf ~/.kube ;
rm -rf /etc/cni/; # 清除容器的网络接口
systemctl restart containerd.service
2.2、Node重置清空方法
rm -rf /etc/cni/net.d;
kubeadm reset;
# 需要重启一下这个服务，避免网络插件有问题
systemctl restart containerd.service
3、网络插件的安装
3.1、当前的网络现状
[root@master1 ~]# journalctl -xefu kubelet
Mar 14 00:08:05 master1 kubelet[3013]: E0314 00:08:05.891756 3013 kubelet.go:2475] "Container runtime network not ready"
networkReady="NetworkReady=false reason:NetworkPluginNotReady message:Network plugin returns error: cni plugin not initialized"
结果显示：
里面提示，cni网络报错，我们需要配置一下网络才可以正常解决这个问题
3.2、安装CNI-flannel插件
# 下载地址
kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml
apiVersion: v1
kind: Namespace
metadata:
labels:
k8s-app: flannel
pod-security.kubernetes.io/enforce: privileged
name: kube-flannel
---
apiVersion: v1
kind: ServiceAccount
metadata:
labels:
k8s-app: flannel
name: flannel
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
k8s-app: flannel
name: flannel
rules:
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- get
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
- apiGroups:
- networking.k8s.io
resources:
- clustercidrs
verbs:
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
labels:
k8s-app: flannel
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
---
apiVersion: v1
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"
}
}
kind: ConfigMap
metadata:
labels:
app: flannel
k8s-app: flannel
tier: node
name: kube-flannel-cfg
namespace: kube-system
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
labels:
app: flannel
k8s-app: flannel
tier: node
name: kube-flannel-ds
namespace: kube-system
spec:
selector:
matchLabels:
app: flannel
k8s-app: flannel
template:
metadata:
labels:
app: flannel
k8s-app: flannel
tier: node
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/os
operator: In
values:
- linux
containers:
- args:
- --ip-masq
- --kube-subnet-mgr
command:
- /opt/bin/flanneld
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- name: EVENT_QUEUE_DEPTH
value: "5000"
image: docker.io/flannel/flannel:v0.21.3
name: kube-flannel
resources:
requests:
cpu: 100m
memory: 50Mi
securityContext:
capabilities:
add:
- NET_ADMIN
- NET_RAW
privileged: false
volumeMounts:
- mountPath: /run/flannel
name: run
- mountPath: /etc/kube-flannel/
name: flannel-cfg
- mountPath: /run/xtables.lock
name: xtables-lock
hostNetwork: true
initContainers:
- args:
- -f
- /flannel
- /opt/cni/bin/flannel
command:
- cp
image: docker.io/flannel/flannel-cni-plugin:v1.1.2
name: install-cni-plugin
volumeMounts:
- mountPath: /opt/cni/bin
name: cni-plugin
- args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
command:
- cp
image: docker.io/flannel/flannel:v0.21.3
name: install-cni
volumeMounts:
- mountPath: /etc/cni/net.d
name: cni
- mountPath: /etc/kube-flannel/
name: flannel-cfg
priorityClassName: system-node-critical
serviceAccountName: flannel
tolerations:
- effect: NoSchedule
operator: Exists
volumes:
- hostPath:
path: /run/flannel
name: run
- hostPath:
path: /opt/cni/bin
name: cni-plugin
- hostPath:
path: /etc/cni/net.d
name: cni
- configMap:
name: kube-flannel-cfg
name: flannel-cfg
- hostPath:
path: /run/xtables.lock
type: FileOrCreate
name: xtables-lock
flannel.yaml3.3、检查是否安装成功
# 查看节点数量
[root@master1 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master1 Ready control-plane 23h v1.26.2
master2 Ready <none> 23h v1.26.2
master3 Ready <none> 23h v1.26.2
# 查询命名空间名字
[root@master1 ~]# kubectl get ns
NAME STATUS AGE
default Active 23h
kube-flannel Active 116s
kube-node-lease Active 23h
kube-public Active 23h
kube-system Active 23h
# 查询是否有flannel运行
[root@master1 ~]# kubectl get pods -n kube-system | grep flannel
kube-flannel-ds-cd5x6 1/1 Running 0 4m33s
kube-flannel-ds-g9j8h 1/1 Running 0 4m49s
kube-flannel-ds-pb66w 1/1 Running 0 4m17s
3.4、多网卡flannel选择网口配置
# 如果Node有多个网卡的话，需要在kube-flannel.yml中使用--iface参数指定集群主机内网网卡
的名称，
# 否则可能会出现dns无法解析。容器无法通信的情况，需要将kube-flannel.yml下载到本地，
# flanneld启动参数加上--iface=<iface-name>
containers:
- name: kube-flannel
image: registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel:v0.10.0-amd64
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
- --iface=eth1
⚠ ⚠ ⚠ --iface=eth1 的值，是你当前的网卡
4、配置crictl
4.1、背景
因为docker查看不了k8s运行镜像的状态，所以要使用crictl查询
4.2、配置
cat >/etc/crictl.yaml<<'EOF'
runtime-endpoint: unix:///var/run/containerd/containerd.sock
image-endpoint: unix:///var/run/containerd/containerd.sock
timeout: 10
debug: false
EOF
4.3、测试
4.3.1、查询运行的pod
[root@node1 ~]# crictl pods
POD ID CREATED STATE NAME NAMESPACE ATTEMPT RUNTIME
98c512f3fb52d 49 minutes ago Ready nginx-deployment-5b47ccdd5c-b9pnc default 0 (default)
548537fb74473 15 hours ago Ready kube-flannel-ds-z4bgg kube-system 0 (default)
6d84a7ce7d3d5 15 hours ago Ready kube-proxy-t7n6h kube-system 0 (default)
4.3.2、批量删除多余的镜像
for image in `crictl images | grep v1.26 | awk '{print $1":"$2}'` ; do crictl rmi $image; done
