kubernetes增删改查，k8s_crud
Kubernetes 中所有的内容都抽象为资源，资源实例化（被调用、被执行了）之后，叫做对象。
环境配置
配置 kubectl 命令别名
echo "alias k='kubectl'" >> ~/.bashrc
echo "alias kd='kubectl describe'" >> ~/.bashrc
echo "alias kg='kubectl get'" >> ~/.bashrc
echo "alias ka='kubectl apply'" >> ~/.bashrc
echo "alias kdl='kubectl delete'" >> ~/.bashrc
source ~/.bashrc
创建普通用户并授权
useradd -m -s /bin/bash igo 2>/dev/null || true
echo 'igo:igo@123' | chpasswd
printf '%s\n' 'igo ALL=(ALL) NOPASSWD:ALL' > /etc/sudoers.d/igo
chmod 440 /etc/sudoers.d/igo
mkdir -p /home/igo/.kube
chown -R igo.igo /home/igo
cp /root/.kube/config /home/igo/.kube/
一条命令加载 kubectl 并创建 config 目录
# 版本号从 docker ps | grep rancher 获取
VER=v1.19.16
VER=v1.25.16 && \
curl -fsSL -o /usr/local/bin/kubectl "https://dl.k8s.io/release/${VER}/bin/linux/amd64/kubectl" && \
chmod +x /usr/local/bin/kubectl && \
kubectl version --client 2>&1 | head -15 && \
mkdir -p /root/.kube
sudo cp kubectlv1.19.16 /usr/local/bin/kubectl
sudo chmod +x /usr/local/bin/kubectl && \
kubectl version --client 2>&1 | head -15
sudo cp kubectlv1.25.16 /usr/local/bin/kubectl
sudo chmod +x /usr/local/bin/kubectl && \
kubectl version --client 2>&1 | head -15
RKE 集群环境
集群管理员权限：
cp /etc/kubernetes/ssl/kubecfg-kube-controller-manager.yaml ~/.kube/config
节点权限：
cp /etc/kubernetes/ssl/kubecfg-kube-node.yaml ~/.kube/config
RKE2 集群环境
echo "export PATH=\$PATH:/var/lib/rancher/rke2/bin" >> ~/.bashrc
echo "export KUBECONFIG=/etc/rancher/rke2/rke2.yaml" >> ~/.bashrc
source ~/.bashrc
查询
节点资源查询
查看已分配的资源：
kubectl describe node k8s-pre-34 | grep -A 15 "Allocated resources"
kubectl describe nodes | awk '/^Name:/{print "\n" $0} /^Allocated resources:/{p=1} p{print} /^Events:/{p=0}'
查看节点 CPU / 内存：
kubectl get nodes -o custom-columns=NAME:.metadata.name,CPU:.status.allocatable.cpu,MEMORY:.status.allocatable.memory | \
awk 'NR==1; NR>1{printf "%s\t%s\t%.1fGi\n", $1, $2, $3/1024/1024}' | column -t
** 查所有node当前负载：**
#!/bin/bash
echo '==================== 节点容量与实时负载 ===================='
printf '%-18s %6s %10s %6s %12s %12s %6s\n' \
NODE CPUS CPU_USE CPU% MEM_TOTAL MEM_USED MEM%
for name in $(kubectl get no --no-headers -o custom-columns=NAME:.metadata.name); do
cpu_cap=$(kubectl get no "$name" -o jsonpath='{.status.capacity.cpu}')
mem_ki=$(kubectl get no "$name" -o jsonpath='{.status.capacity.memory}')
mem_ki=${mem_ki%Ki}
if [ -n "$mem_ki" ]; then mem_cap="$((mem_ki / 1024 / 1024))Gi"; else mem_cap='-'; fi
read -r cpu_use cpu_pct mem_use mem_pct <<< "$(
kubectl top no --no-headers 2>/dev/null | awk -v n="$name" '$1 == n { print $2, $3, $4, $5 }'
)"
[ -z "$cpu_use" ] && cpu_use=- cpu_pct=- mem_use=- mem_pct=-
printf '%-18s %6s %10s %6s %12s %12s %6s\n' \
"$name" "$cpu_cap" "$cpu_use" "$cpu_pct" "$mem_cap" "$mem_use" "$mem_pct"
done
查指定node的mem,cpu前2POD
no='10.193.236.203'; echo "=== MEM Top2 @ $no ==="; kubectl top po -A --no-headers 2>/dev/null | awk -v n="$no" 'BEGIN{c="kubectl get po -A --field-selector spec.nodeName="n" --no-headers -o custom-columns=NS:.metadata.namespace,POD:.metadata.name";while((c|getline)>0)k[$1"\t"$2]=1;close(c)} k[$1"\t"$2]{print}' | sort -k4 -hr | head -2; echo "=== CPU Top2 @ $no ==="; kubectl top po -A --no-headers 2>/dev/null | awk -v n="$no" 'BEGIN{c="kubectl get po -A --field-selector spec.nodeName="n" --no-headers -o custom-columns=NS:.metadata.namespace,POD:.metadata.name";while((c|getline)>0)k[$1"\t"$2]=1;close(c)} k[$1"\t"$2]{print}' | sort -k3 -hr | head -2
查指定node的mem前2POD
no='10.193.236.203'; kubectl top po -A --no-headers 2>/dev/null | awk -v n="$no" 'BEGIN{c="kubectl get po -A --field-selector spec.nodeName="n" --no-headers -o custom-columns=NS:.metadata.namespace,POD:.metadata.name";while((c|getline)>0)k[$1"\t"$2]=1;close(c)} k[$1"\t"$2]{print}' | sort -k4 -hr | head -2
节点扩容后需要重启 kubelet 才会生效：
ansible 10.80.238.34,10.80.238.36 -m shell -a "systemctl restart kubelet"
Pod 相关查询
列出 Pod 里的 containers：
kubectl get pod jenkins-0 -n jenkins -o jsonpath="{range .spec.containers[*]}{.name}{'\t'}{.image}{'\n'}{end}"
查看 Deployment 环境变量：
kubectl get deploy mes-server-deployment -n mes-app -o jsonpath='{.spec.template.spec.containers[0].env}'
增加（创建）
创建资源
kubectl create -f kubernetes-demo.yaml # 使用预定义文件创建资源
kubectl apply -f ./igo01.yaml -f ./igo02.yaml # 使用多个文件
kubectl apply -f https://k8s.io/examples/application/mysql/mysql-pv.yaml
kubectl run nginx --image=nginx --replicas=3 --dry-run
交互式创建 MySQL 客户端 Pod
kubectl run -it --rm --image=mysql:5.6 --restart=Never mysql-client -- mysql -h mysql -ppassword
创建 CronJob
kubectl create cronjob hello \
--image=busybox:1.28 \
--schedule="*/1 * * * *" \
-- echo "Hello World"
给 Pod 添加标签
kubectl label pods/pod-demo env=production
YAML 方式创建多个 Pod
kubectl apply -f - <<EOF
apiVersion: v1
kind: Pod
metadata:
name: busybox-sleep
spec:
containers:
- name: busybox
image: busybox:1.28
args:
- sleep
- "1000000"
---
apiVersion: v1
kind: Pod
metadata:
name: busybox-sleep-less
spec:
containers:
- name: busybox
image: busybox:1.28
args:
- sleep
- "1000"
EOF
设置环境变量
kubectl set env deploy/mes-server-deployment TZ=Europe/Budapest -n mes-app
kubectl set env deploy --all TZ=Europe/Budapest -n mes-app
修改
修改标签
kubectl label pods/pod-demo env=testing --overwrite
副本扩容 / 缩容
kubectl scale --replicas=3 rs/igo # 将 ig o副本集调整到 3 副本
kubectl scale --current-replicas=2 --replicas=3 deployment/mysql # 如果当前是 2，调整到 3
端口转发
监听本地 5000 转发到 ig o-deployment 创建的 Pod 的 6000 端口：
kubectl port-forward deploy/igo-deployment 5000:6000
Deployment 扩容（补充）
# 查看 Deployment 副本数
kubectl get deployment rancher -n cattle-system
# 示例：将 cattle-system 命名空间下的 rancher Deployment 副本数改为 3
kubectl scale deployment rancher -n cattle-system --replicas=3
# 编辑 Deployment
kubectl edit deployment rancher -n cattle-system
删除
删除资源
kubectl label pods igo-pod bar- # 删除 igo-pod 容器的 bar 标签
kubectl delete pod igo-pod --now # 立刻删除
kubectl delete pods,deployment,svc -l name=myLabel # 按标签批量删除
kubectl delete -f ./igopod.json # 根据文件删除
删除 PVC / PV
kubectl delete pvc mysql-pv-claim
kubectl delete pv mysql-pv-volume
交互
进入 Pod 执行命令
kubectl exec --stdin --tty igo-pod -- /bin/sh
查看资源使用量（按 CPU 排序）
kubectl top pod POD_NAME --sort-by=cpu
文件拷贝
kubectl cp /tmp/foo_dir igo-pod:/tmp/bar_dir