kubernetes中Pod资源的操作
一、资源限制：pod和container的资源请求和限制：
spec.containers[].resources.limits.cpu ???????#cpu上限
spec.containers[].resources.limits.memory ??#内存上限
spec.containers[].resources.requests.cpu ????#创建时分配的基本cpu资源
spec.containers[].resources.requests.memory ?#创建时分配的基本内存资源
示例（在master1上操作）：# vim pod2.yamlapiVersion: v1kind: Podmetadata: name: frontend ???#Pod资源的名称spec: containers: - name: db ???#容器1的名称 ?image: mysql ?env: ?- name: MYSQL_ROOT_PASSWORD ??value: "password" ?resources: ??requests: ???memory: "64Mi" ???cpu: "250m" ??limits: ???memory: "128Mi" ???cpu: "500m" - name: wp ???#容器2的名称 ?image: wordpress ?resources: ??requests: ???memory: "64Mi" ???cpu: "250m" ??limits: ???memory: "128Mi" ???cpu: "500m"#插入完成后，按Esc退出插入模式，输入:wq保存退出`创建资源`# kubectl apply -f pod2.yamlpod/frontend created`查看资源详细信息`# kubectl describe pod frontendName: ???????frontendNamespace: ????defaultPriority: ?????0PriorityClassName: <none>Node: ???????192.168.18.148/192.168.18.148 ???#被分配到的节点为node1......此处省略多行Events: Type ?Reason ??Age ?From ??????????Message ---- ?------ ??---- ---- ??????????------- Normal Scheduled 89s ?default-scheduler ???Successfully assigned default/frontend to 192.168.18.148 Normal Pulling ?88s ?kubelet, 192.168.18.148 pulling image "mysql" Normal Pulled ??23s ?kubelet, 192.168.18.148 Successfully pulled image "mysql" Normal Created ?23s ?kubelet, 192.168.18.148 Created container Normal Started ?22s ?kubelet, 192.168.18.148 Started container Normal Pulling ?22s ?kubelet, 192.168.18.148 pulling image "wordpress" ???#处于镜像拉取wordpress状态# kubectl get podsNAME ???????????????READY ?STATUS ?RESTARTS ?AGEfrontend ?????????????2/2 ??Running ?0 ????4m26s#此时两个容器就会处于Running运行状态`查看对应节点上Pod资源的占用情况`# kubectl describe nodes 192.168.18.148Name: ???????192.168.18.148......此处省略多行Allocated resources: (Total limits may be over 100 percent, i.e., overcommitted.) Resource Requests ??Limits -------- -------- ??------ cpu ???550m (55%) ?1100m (110%) ???#核心资源 memory ?228Mi (13%) 556Mi (32%) ???#上限资源`查看命名空间`# kubectl get nsNAME ????STATUS ?AGEdefault ???Active ?13dkube-public ?Active ?13dkube-system ?Active ?13d#只要不用-n指定，出现的就是默认的这三个二、重启策略：1：Always：当容器终止推出后，总是重启容器，默认策略
2：Onfailure：当容器异常退出（退出码为非0）时，重启容器
3：Never：当容器终止退出，从不重启资源
注意：k8s中不支持重启pod资源，只有删除重建
示例（在master1上操作）：`默认的重启策略是Always`# kubectl edit deploy#输入/restartPolicy查找restartPolicy: Always ???#没有设定重启策略时默认为Always# vim pod3.yamlapiVersion: v1kind: Podmetadata: name: foospec: containers: - name: busybox ?image: busybox ?args: ???#参数 ?- /bin/sh ?#在shell环境中 ?- -c ???#command命令 ?- sleep 30; exit 3 ??#容器启动后休眠30s，异常退出返回状态码为非0值#插入完成后，按Esc退出插入模式，输入:wq保存退出# kubectl apply -f pod3.yamlpod/foo created# kubectl get podsNAME ???????????????READY ?STATUS ??????RESTARTS ?AGEfoo ????????????????0/1 ??ContainerCreating ?0 ????18s#其中有RESTARTS重启值，此时为0# kubectl get podsNAME ???????????????READY ?STATUS ?RESTARTS ?AGEfoo ????????????????0/1 ??Error ??0 ????62s#此时出现Error报错，因为我i们刚刚设置的异常退出，一会再查看时RESTARTS重启值会变为1、`这个就是依照其中的重启策略去执行的`# kubectl get podsNAME ???????????????READY ?STATUS ?RESTARTS ?AGEfoo ????????????????1/1 ??Running ?1 ????3m13s`先删除之前创建的资源，因为会占用`# kubectl delete -f pod3.yamlpod "foo" deleted# kubectl delete -f pod2.yamlpod "frontend" deleted`添加重启策略Never`# vim pod3.yamlapiVersion: v1kind: Podmetadata: name: foospec: containers: - name: busybox ?image: busybox ?args: ?- /bin/sh ?- -c ?- sleep 10 ??????#修改休眠时间为10s restartPolicy: Never ??#添加重启策略#修改完成后，按Esc退出插入模式，输入:wq保存退出# kubectl apply -f pod3.yamlpod/foo created# kubectl get podsNAME ???????????????READY ?STATUS ?RESTARTS ?AGEfoo ????????????????1/1 ??Running ?0 ????14s# kubectl get podsNAME ???????????????READY ?STATUS ??RESTARTS ?AGEfoo ????????????????0/1 ??Completed ?0 ????65s#此时资源创建完成，不需要使用的状态下会自动休眠，因为之间添加了重启策略，所以不会进行重启三、健康检查：又称为探针（Probe）注意：规则可以同时定义livenessProbe 如果检查失败，将杀死容器，根据Pod的restartPolicy来操作
ReadinessProbe 如果检查失败，kubernetes会把Pod从service endpoints后端节点中中剔除
Probe支持三种检查方法：httpGet 发送http请求，返回200-400范围状态码为成功
exec 执行Shell命令返回状态码是0为成功
tcpSocket 发起TCP Socket建立成功
示例exec方式（在master1上操作）：# vim pod4.yamlapiVersion: v1kind: Podmetadata: labels: ?test: liveness name: liveness-execspec: containers: - name: liveness ?image: busybox ?args: ?- /bin/sh ?- -c ?- touch /tmp/healthy; sleep 30; rm -rf /tmp/healthy ??#创建一个空文件，休眠30s，删除这个空文件 ?livenessProbe: ???exec: ??#探测健康 ???command: ?#command命令 ???- cat ???#执行查看 ???- /tmp/healthy ??#创建的空文件 ??initialDelaySeconds: 5 ?#容器创建完成5秒之后开始健康检查 ??periodSeconds: 5 ????#检查的间隔频率为5秒`休眠之前检查状态返回值为0，30秒休眠结束之后再检查，因为没有这个文件了就会返回非0值``刷新资源`# kubectl apply -f pod4.yamlpod/liveness-exec created# kubectl get podsNAME ???????????????READY ?STATUS ??RESTARTS ?AGEliveness-exec ???????????1/1 ??Running ??0 ????24s# kubectl get podsNAME ???????????????READY ?STATUS ??RESTARTS ?AGEliveness-exec ???????????0/1 ??Completed ?0 ????53s# kubectl get podsNAME ???????????????READY ?STATUS ??RESTARTS ?AGEliveness-exec ???????????1/1 ??Running ??1 ????67s# kubectl get podsNAME ???????????????READY ?STATUS ??????RESTARTS ?AGEliveness-exec ???????????0/1 ??CrashLoopBackOff ?1 ????109s# kubectl get podsNAME ???????????????READY ?STATUS ??RESTARTS ?AGEliveness-exec ???????????1/1 ??Running ??2 ????2m5s#当中状态不断改变，就代表它正在不断的进行检查，然后不断的执行重启策略，其中的RESTARTS重启值也会随之增加
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