1.列出pod并排序
2.找出pod中的错误日志
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$ kubectl logs mypod-798fcd9949-lk9rc | grep error > xx.log
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3.创建一个pod ，并调度到某个节点上
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| $ cat > pod.yaml << EOF
apiVersion: v1
kind: Pod
metadata:
name: nginx
labels:
env: test
spec:
containers:
- name: nginx
image: nginx
imagePullPolicy: IfNotPresent
nodeSelector:
disktype: ssd
EOF
$ kubectl create -f pod.yaml
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4.列出正常节点的个数
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| $ kubectl get node | grep -w Ready
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5.pod中挂载volume
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| apiVersion: v1
kind: Pod
metadata:
name: test-pd
spec:
containers:
- image: k8s.gcr.io/test-webserver
name: test-container
volumeMounts:
- mountPath: /cache
name: cache-volume
volumes:
- name: cache-volume
emptyDir: {}
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更详细用法参考官方文档：https://kubernetes.io/docs/concepts/storage/volumes/
6.提供一个pod，添加init-container ,在container中添加一个空文件，启动的时候。在另一个containre中检测是否有这个文件，否则退出
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| apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: nginx-pod
name: nginx-pod
spec:
containers:
- image: nginx
name: nginx-pod
command: ['sh','-c','if [ -f "a.txt" ]; then echo xx ;fi']
ports:
- containerPort: 80
resources: {}
volumeMounts:
- name: workdir
mountPath: /usr/nginx/html
dnsPolicy: ClusterFirst
initContainers:
- image: busybox
name: initcheck
command: ['sh','-c','touch /tmp/index.html']
volumeMounts:
- name: workdir
mountPath: /tmp
volumes:
- name: workdir
emptyDir: {}
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7.创建pod，再创建一个service
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| apiVersion: v1
kind: Pod
metadata:
name: nats
labels:
app: nats
spec:
containers:
- name: nats
image: nats
---
apiVersion: v1
kind: Service
metadata:
name: nats
spec:
selector:
app: nats
ports:
- port: 4222
nodePort: 32222
type: NodePort
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8.在一个pod中创建2个容器，如redis+nginx
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| apiVersion: v1
kind: Pod
metadata:
name: demo
spec:
containers:
- image: nginx
name: nginx
- image: redis
name: redis
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9.找到指定service下的pod中，cpu利用率按高到底排序
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| $ kubectl top pods --selector="app=demo" | grep -v NAME | sort -k 2 -nr
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10.创建一个简单的daemonset
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| apiVersion: apps/v1
kind: DaemonSet
metadata:
name: fluentd-elasticsearch
namespace: kube-system
labels:
k8s-app: fluentd-logging
spec:
selector:
matchLabels:
name: fluentd-elasticsearch
template:
metadata:
labels:
name: fluentd-elasticsearch
spec:
tolerations:
- key: node-role.kubernetes.io/master
effect: NoSchedule
containers:
- name: fluentd-elasticsearch
image: quay.io/fluentd_elasticsearch/fluentd:v2.5.2
resources:
limits:
memory: 200Mi
requests:
cpu: 100m
memory: 200Mi
volumeMounts:
- name: varlog
mountPath: /var/log
- name: varlibdockercontainers
mountPath: /var/lib/docker/containers
readOnly: true
terminationGracePeriodSeconds: 30
volumes:
- name: varlog
hostPath:
path: /var/log
- name: varlibdockercontainers
hostPath:
path: /var/lib/docker/containers
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11.deployment的扩容 ，scale命令
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| $ kubectl scale --replicas=4 deployment demo
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12 创建secret，有一个paasword字段（手动base64加密），创建两个pod引用该secret，一个用env ,一个用volume来调用
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| $ echo -n 'admin' | base64
YWRtaW4=
$ echo -n '1f2d1e2e67df' | base64
MWYyZDFlMmU2N2Rm
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现在可以像这样写一个 secret 对象：
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| apiVersion: v1
kind: Secret
metadata:
name: mysecret
type: Opaque
data:
username: YWRtaW4=
password: MWYyZDFlMmU2N2Rm
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使用 kubectl apply 创建 secret：
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| $ kubectl apply -f ./secret.yaml
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Pod 中使用 Secret 作为环境变量的示例：
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| apiVersion: v1
kind: Pod
metadata:
name: secret-env-pod
spec:
containers:
- name: mycontainer
image: redis
env:
- name: SECRET_USERNAME
valueFrom:
secretKeyRef:
name: mysecret
key: username
- name: SECRET_PASSWORD
valueFrom:
secretKeyRef:
name: mysecret
key: password
restartPolicy: Never
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Pod 中使用 volume 挂在 secret 的例子：
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| apiVersion: v1
kind: Pod
metadata:
name: mypod
spec:
containers:
- name: mypod
image: redis
volumeMounts:
- name: foo
mountPath: "/etc/foo"
readOnly: true
volumes:
- name: foo
secret:
secretName: mysecret
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官方链接：https://kubernetes.io/docs/concepts/configuration/secret/
13.先将nginx:1.9的deployment，升级到nginx:1.11，记录下来(—record)，然后回滚到1.9
升级
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| $ kubectl set image deployments demo demo=nginx:1.11 --record
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回滚
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| $ kubectl rollout undo deployment demo
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14.使用 nslookup 查看service 和pod的dns
service 和pod 的创建用之前的 yaml
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$ kubectl run -it
$ nslookup svc-demo.kube-system.svc.cluster.local
$ nslookup 1-2-3-4.default.pod.cluster.local
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参考文档：https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/
15.etcdctl 来 备份etcd
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$ ETCDCTL_API=3 etcdctl --cacert=/opt/kubernetes/ssl/ca.pem --cert=/opt/kubernetes/ssl/server.pem --key=/opt/kubernetes/ssl/server-key.pem --endpoints=https://192.168.1.36:2379 snapshot save /data/etcd_backup_dir/etcd-snapshot-`date +%Y%m%d`.db
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参考文档地址：https://kubernetes.io/docs/tasks/administer-cluster/configure-upgrade-etcd/
16.static pod 的使用
找到 --pod-manifest-path=/etc/kubelet.d/ 配置的位置，然后把 pod 的 yaml 放进去
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| apiVersion: v1
kind: Pod
metadata:
name: static-web
labels:
role: myrole
spec:
containers:
- name: web
image: nginx
ports:
- name: web
containerPort: 80
protocol: TCP
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参考文档地址：https://kubernetes.io/docs/tasks/administer-cluster/static-pod/
17.在一个新的namespace创建pod
先创建 ns
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| # 创建 ns
$ kubectl create namespace test
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再创建 pod
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| apiVersion: v1
kind: Pod
metadata:
name: demo
namespace: test
spec:
containers:
- image: nginx
name: nginx
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18.pv 类型 hostpath 位置在/data，大小为1G, readonly 模式
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| apiVersion: v1
kind: PersistentVolume
metadata:
name: example-pv
spec:
capacity:
storage: 1Gi
volumeMode: Filesystem
accessModes:
- ReadOnlyMany
persistentVolumeReclaimPolicy: Delete
local:
path: /data
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- test-node
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参考文档地址：https://kubernetes.io/docs/concepts/storage/persistent-volumes/
20.给pod创建service
Pod 配置文件
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| apiVersion: v1
kind: Pod
metadata:
name: nginx
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
imagePullPolicy: IfNotPresent
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service 配置文件，通过 labels app=nginx 关联 pod
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| apiVersion: v1
kind: Service
metadata:
name: nginx
labels:
app: nginx
spec:
ports:
- port: 80
protocol: TCP
selector:
app: nginx
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21.使用node selector，选择disk为ssd的机器调度
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| apiVersion: v1
kind: Pod
metadata:
name: nginx
labels:
env: test
spec:
containers:
- name: nginx
image: nginx
imagePullPolicy: IfNotPresent
nodeSelector:
disktype: ssd
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22.排查apiserver连接不上问题：
下面例举一些可能导致的原因：
- 1、apiserver 有负载均衡，负载均衡服务有问题，或者负载均衡服务连接不上后端apiserver
- 2、TLS证书过期，分两种情况：
- 2.1、整个集群证书过期
- 2.2、ETCD证书和K8S集群证书分开颁发，只有ETCD集群证书过期，或者k8s内部证书过期
- 3、apiserver 服务连接过多，导致连接不上
- 4、k8s集群规则大，导致etcd集群响应慢，apiserver接口服务也受到影响（因为 apiserver 是k8s集群唯一数据查询与写入口）
还有其它原因，本文只例举这些。
23.把一个node弄成unavailable 并且把上边的pod重新调度去新的node上
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| $ kubectl drain ${node-name} --delete-local-data=true --ignore-daemonsets=true
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真题日期
参考链接
