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kubernetes系列教程(六)kubernetes资源管理和服务质量

发表于：2024-11-17 作者：千家信息网编辑

千家信息网最后更新 2024年11月17日，写在前面上一篇文章中kubernetes系列教程（五）深入掌握核心概念pod初步介绍了yaml学习kubernetes中重要的一个概念pod，接下来介绍kubernetes系列教程pod的resour

千家信息网最后更新 2024年11月17日kubernetes系列教程(六)kubernetes资源管理和服务质量

写在前面

上一篇文章中kubernetes系列教程（五）深入掌握核心概念pod初步介绍了yaml学习kubernetes中重要的一个概念pod，接下来介绍kubernetes系列教程pod的resource资源管理和pod的Quality of service服务质量。

1. Pod资源管理

1.1 resource定义

容器运行过程中需要分配所需的资源，如何与cggroup联动配合呢？答案是通过定义resource来实现资源的分配，资源的分配单位主要是cpu和memory，资源的定义分两种：requests和limits，requests表示请求资源，主要用于初始kubernetes调度pod时的依据，表示必须满足的分配资源;limits表示资源的限制，即pod不能超过limits定义的限制大小，超过则通过cggroup限制，pod中定义资源可以通过下面四个字段定义：

spec.container[].resources.requests.cpu 请求cpu资源的大小，如0.1个cpu和100m表示分配1/10个cpu；
spec.container[].resources.requests.memory 请求内存大小，单位可用M，Mi，G，Gi表示；
spec.container[].resources.limits.cpu 限制cpu的大小，不能超过阀值，cggroup中限制的值；
spec.container[].resources.limits.memory 限制内存的大小，不能超过阀值，超过会发生OOM；

1、开始学习如何定义pod的resource资源,如下以定义nginx-demo为例，容器请求cpu资源为250m，限制为500m，请求内存资源为128Mi，限制内存资源为256Mi，当然也可以定义多个容器的资源，多个容器相加就是pod的资源总资源，如下：

[root@node-1 demo]#cat nginx-resource.yaml apiVersion: v1kind: Podmetadata:  name: nginx-demo  labels:    name: nginx-demospec:  containers:  - name: nginx-demo    image: nginx:1.7.9    imagePullPolicy: IfNotPresent    ports:    - name: nginx-port-80      protocol: TCP      containerPort: 80    resources:      requests:        cpu: 0.25        memory: 128Mi      limits:        cpu: 500m        memory: 256Mi

2、应用pod的配置定义(如之前的pod还存在，先将其删除kubectl delete pod ),或pod命名为另外一个名

[root@node-1 demo]# kubectl apply -f nginx-resource.yaml pod/nginx-demo created

3、查看pod资源的分配详情

[root@node-1 demo]# kubectl get podsNAME                    READY   STATUS    RESTARTS   AGEdemo-7b86696648-8bq7h   1/1     Running   0          12ddemo-7b86696648-8qp46   1/1     Running   0          12ddemo-7b86696648-d6hfw   1/1     Running   0          12dnginx-demo              1/1     Running   0          94s[root@node-1 demo]# kubectl describe pods nginx-demo  Name:         nginx-demoNamespace:    defaultPriority:     0Node:         node-3/10.254.100.103Start Time:   Sat, 28 Sep 2019 12:10:49 +0800Labels:       name=nginx-demoAnnotations:  kubectl.kubernetes.io/last-applied-configuration:                {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"labels":{"name":"nginx-demo"},"name":"nginx-demo","namespace":"default"},"sp...Status:       RunningIP:           10.244.2.13Containers:  nginx-demo:    Container ID:   docker://55d28fdc992331c5c58a51154cd072cd6ae37e03e05ae829a97129f85eb5ed79    Image:          nginx:1.7.9    Image ID:       docker-pullable://nginx@sha256:e3456c851a152494c3e4ff5fcc26f240206abac0c9d794affb40e0714846c451    Port:           80/TCP    Host Port:      0/TCP    State:          Running      Started:      Sat, 28 Sep 2019 12:10:51 +0800    Ready:          True    Restart Count:  0    Limits:        #限制资源      cpu:     500m      memory:  256Mi    Requests:      #请求资源      cpu:        250m      memory:     128Mi    Environment:      ...省略...

4、Pod的资源如何分配呢？毫无疑问是从node上分配的，当我们创建一个pod的时候如果设置了requests，kubernetes的调度器kube-scheduler会执行两个调度过程：filter过滤和weight称重，kube-scheduler会根据请求的资源过滤，把符合条件的node筛选出来，然后再进行排序，把最满足运行pod的node筛选出来，然后再特定的node上运行pod。调度算法和细节可以参考下kubernetes调度算法介绍。如下是node-3节点资源的分配详情：

[root@node-1 ~]# kubectl describe node node-3...省略...Capacity:    #节点上资源的总资源情况，1个cpu，2g内存，110个pod cpu:                1 ephemeral-storage:  51473888Ki hugepages-2Mi:      0 memory:             1882352Ki pods:               110Allocatable: #节点容许分配的资源情况，部分预留的资源会排出在Allocatable范畴 cpu:                1 ephemeral-storage:  47438335103 hugepages-2Mi:      0 memory:             1779952Ki pods:               110System Info: Machine ID:                 0ea734564f9a4e2881b866b82d679dfc System UUID:                FFCD2939-1BF2-4200-B4FD-8822EBFFF904 Boot ID:                    293f49fd-8a7c-49e2-8945-7a4addbd88ca Kernel Version:             3.10.0-957.21.3.el7.x86_64 OS Image:                   CentOS Linux 7 (Core) Operating System:           linux Architecture:               amd64 Container Runtime Version:  docker://18.6.3 Kubelet Version:            v1.15.3 Kube-Proxy Version:         v1.15.3PodCIDR:                     10.244.2.0/24Non-terminated Pods:         (3 in total) #节点上运行pod的资源的情况，除了nginx-demo之外还有多个pod  Namespace                  Name                           CPU Requests  CPU Limits  Memory Requests  Memory Limits  AGE  ---------                  ----                           ------------  ----------  ---------------  -------------  ---  default                    nginx-demo                     250m (25%)    500m (50%)  128Mi (7%)       256Mi (14%)    63m  kube-system                kube-flannel-ds-amd64-jp594    100m (10%)    100m (10%)  50Mi (2%)        50Mi (2%)      14d  kube-system                kube-proxy-mh3gq               0 (0%)        0 (0%)      0 (0%)           0 (0%)         12dAllocated resources:  #已经分配的cpu和memory的资源情况  (Total limits may be over 100 percent, i.e., overcommitted.)  Resource           Requests     Limits  --------           --------     ------  cpu                350m (35%)   600m (60%)  memory             178Mi (10%)  306Mi (17%)  ephemeral-storage  0 (0%)       0 (0%)Events:

1.2 资源分配原理

Pod的定义的资源requests和limits作用于kubernetes的调度器kube-sheduler上，实际上cpu和内存定义的资源会应用在container上，通过容器上的cggroup实现资源的隔离作用，接下来我们介绍下资源分配的原理。

spec.containers[].resources.requests.cpu 作用在CpuShares，表示分配cpu 的权重，争抢时的分配比例
spec.containers[].resources.requests.memory 主要用于kube-scheduler调度器，对容器没有设置意义
spec.containers[].resources.limits.cpu 作用CpuQuota和CpuPeriod，单位为微秒，计算方法为：CpuQuota/CpuPeriod，表示最大cpu最大可使用的百分比，如500m表示允许使用1个cpu中的50%资源
spec.containers[].resources.limits.memory 作用在Memory，表示容器最大可用内存大小，超过则会OOM

以上面定义的nginx-demo为例，研究下pod中定义的requests和limits应用在docker生效的参数：

1、查看pod所在的node节点，nginx-demo调度到node-3节点上

[root@node-1 ~]# kubectl get pods -o wide nginx-demoNAME         READY   STATUS    RESTARTS   AGE   IP            NODE     NOMINATED NODE   READINESS GATESnginx-demo   1/1     Running   0          96m   10.244.2.13   node-3

2、获取容器的id号，可以通过kubectl describe pods nginx-demo的containerID获取到容器的id，或者登陆到node-3节点通过名称过滤获取到容器的id号，默认会有两个pod：一个通过pause镜像创建，另外一个通过应用镜像创建

[root@node-3 ~]# docker container  list |grep nginx55d28fdc9923        84581e99d807           "nginx -g 'daemon of…"   2 hours ago         Up 2 hours                                   k8s_nginx-demonginx-demo_default_66958ef7-507a-41cd-a688-7a4976c6a71e_02fe0498ea9b5        k8s.gcr.io/pause:3.1   "/pause"                 2 hours ago         Up 2 hours                                   k8s_POD_nginx-demo_default_66958ef7-507a-41cd-a688-7a4976c6a71e_0

3、查看docker容器详情信息

[root@node-3 ~]# docker container inspect 55d28fdc9923[...部分输出省略...    {        "Image": "sha256:84581e99d807a703c9c03bd1a31cd9621815155ac72a7365fd02311264512656",        "ResolvConfPath": "/var/lib/docker/containers/2fe0498ea9b5dfe1eb63eba09b1598a8dfd60ef046562525da4dcf7903a25250/resolv.conf",        "HostConfig": {            "Binds": [                "/var/lib/kubelet/pods/66958ef7-507a-41cd-a688-7a4976c6a71e/volumes/kubernetes.io~secret/default-token-5qwmc:/var/run/secrets/kubernetes.io/serviceaccount:ro",                "/var/lib/kubelet/pods/66958ef7-507a-41cd-a688-7a4976c6a71e/etc-hosts:/etc/hosts",                "/var/lib/kubelet/pods/66958ef7-507a-41cd-a688-7a4976c6a71e/containers/nginx-demo/1cc072ca:/dev/termination-log"            ],            "ContainerIDFile": "",            "LogConfig": {                "Type": "json-file",                "Config": {                    "max-size": "100m"                }            },            "UTSMode": "",            "UsernsMode": "",            "ShmSize": 67108864,            "Runtime": "runc",            "ConsoleSize": [                0,                0            ],            "Isolation": "",            "CpuShares": 256,        CPU分配的权重，作用在requests.cpu上            "Memory": 268435456,     内存分配的大小，作用在limits.memory上            "NanoCpus": 0,            "CgroupParent": "kubepods-burstable-pod66958ef7_507a_41cd_a688_7a4976c6a71e.slice",            "BlkioWeight": 0,            "BlkioWeightDevice": null,            "BlkioDeviceReadBps": null,            "BlkioDeviceWriteBps": null,            "BlkioDeviceReadIOps": null,            "BlkioDeviceWriteIOps": null,            "CpuPeriod": 100000,    CPU分配的使用比例，和CpuQuota一起作用在limits.cpu上            "CpuQuota": 50000,            "CpuRealtimePeriod": 0,            "CpuRealtimeRuntime": 0,            "CpusetCpus": "",            "CpusetMems": "",            "Devices": [],            "DeviceCgroupRules": null,            "DiskQuota": 0,            "KernelMemory": 0,            "MemoryReservation": 0,            "MemorySwap": 268435456,            "MemorySwappiness": null,            "OomKillDisable": false,            "PidsLimit": 0,            "Ulimits": null,            "CpuCount": 0,            "CpuPercent": 0,            "IOMaximumIOps": 0,            "IOMaximumBandwidth": 0,        },       }]

1.3. cpu资源测试

pod中cpu的限制主要通过requests.cpu和limits.cpu来定义，limits是不能超过的cpu大小，我们通过stress镜像来验证，stress是一个cpu和内存的压侧工具，通过指定args参数的定义压侧cpu的大小。监控pod的cpu和内存可通过kubectl top的方式来查看，依赖于监控组件如metric-server或promethus，当前没有安装，我们通过docker stats的方式来查看。

1、通过stress镜像定义一个pod，分配0.25个cores和最大限制0.5个core使用比例

[root@node-1 demo]# cat cpu-demo.yaml apiVersion: v1kind: Podmetadata:  name: cpu-demo  namespace: default  annotations:     kubernetes.io/description: "demo for cpu requests and"spec:  containers:  - name: stress-cpu    image: vish/stress    resources:      requests:        cpu: 250m      limits:        cpu: 500m    args:    - -cpus    - "1"

2、应用yaml文件生成pod

[root@node-1 demo]# kubectl apply -f cpu-demo.yaml pod/cpu-demo created

3、查看pod资源分配详情

[root@node-1 demo]# kubectl describe pods cpu-demo Name:         cpu-demoNamespace:    defaultPriority:     0Node:         node-2/10.254.100.102Start Time:   Sat, 28 Sep 2019 14:33:12 +0800Labels:       Annotations:  kubectl.kubernetes.io/last-applied-configuration:                {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{"kubernetes.io/description":"demo for cpu requests and"},"name":"cpu-demo","nam...              kubernetes.io/description: demo for cpu requests andStatus:       RunningIP:           10.244.1.14Containers:  stress-cpu:    Container ID:  docker://14f93767ad37b92beb91e3792678f60c9987bbad3290ae8c29c35a2a80101836    Image:         progrium/stress    Image ID:      docker-pullable://progrium/stress@sha256:e34d56d60f5caae79333cee395aae93b74791d50e3841986420d23c2ee4697bf    Port:              Host Port:         Args:      -cpus      1    State:          Waiting      Reason:       CrashLoopBackOff    Last State:     Terminated      Reason:       Error      Exit Code:    1      Started:      Sat, 28 Sep 2019 14:34:28 +0800      Finished:     Sat, 28 Sep 2019 14:34:28 +0800    Ready:          False    Restart Count:  3    Limits:         #cpu限制使用的比例      cpu:  500m    Requests:       #cpu请求的大小      cpu:  250m

4、登陆到特定的node节点，通过docker container stats查看容器的资源使用详情

在pod所属的node上通过top查看，cpu的使用率限制百分比为50%。

通过上面的验证可以得出结论，我们在stress容器中定义使用1个core，通过limits.cpu限定可使用的cpu大小是500m，测试验证pod的资源已在容器内部或宿主机上都严格限制在50%（node机器上只有一个cpu，如果有2个cpu则会分摊为25%）。

1.4 memory资源测试

1、通过stress镜像测试验证requests.memory和limits.memory的生效范围，limits.memory定义容器可使用的内存资源大小，当超过内存设定的大小后容器会发生OOM，如下定义一个测试的容器，最大内存不能超过512M,使用stress镜像--vm-bytes定义压侧内存大小为256Mi

[root@node-1 demo]# cat memory-demo.yaml apiVersion: v1kind: Podmetadata:  name: memory-stress-demo  annotations:    kubernetes.io/description: "stress demo for memory limits"spec:  containers:  - name: memory-stress-limits    image: polinux/stress    resources:      requests:        memory: 128Mi      limits:        memory: 512Mi    command: ["stress"]    args: ["--vm", "1", "--vm-bytes", "256M", "--vm-hang", "1"]

2、应用yaml文件生成pod

[root@node-1 demo]# kubectl apply -f memory-demo.yaml pod/memory-stress-demo created[root@node-1 demo]# kubectl get pods memory-stress-demo -o wide NAME                 READY   STATUS    RESTARTS   AGE   IP            NODE     NOMINATED NODE   READINESS GATESmemory-stress-demo   1/1     Running   0          41s   10.244.1.19   node-2

3、查看资源的分配情况

[root@node-1 demo]# kubectl describe  pods memory-stress-demoName:         memory-stress-demoNamespace:    defaultPriority:     0Node:         node-2/10.254.100.102Start Time:   Sat, 28 Sep 2019 15:13:06 +0800Labels:       Annotations:  kubectl.kubernetes.io/last-applied-configuration:                {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{"kubernetes.io/description":"stress demo for memory limits"},"name":"memory-str...              kubernetes.io/description: stress demo for memory limitsStatus:       RunningIP:           10.244.1.16Containers:  memory-stress-limits:    Container ID:  docker://c7408329cffab2f10dd860e50df87bd8671e65a0f8abb4dae96d059c0cb6bb2d    Image:         polinux/stress    Image ID:      docker-pullable://polinux/stress@sha256:6d1825288ddb6b3cec8d3ac8a488c8ec2449334512ecb938483fc2b25cbbdb9a    Port:              Host Port:         Command:      stress    Args:      --vm      1      --vm-bytes      256Mi      --vm-hang      1    State:          Waiting      Reason:       CrashLoopBackOff    Last State:     Terminated      Reason:       Error      Exit Code:    1      Started:      Sat, 28 Sep 2019 15:14:08 +0800      Finished:     Sat, 28 Sep 2019 15:14:08 +0800    Ready:          False    Restart Count:  3    Limits:          #内存限制大小      memory:  512Mi    Requests:         #内存请求大小      memory:     128Mi    Environment:      Mounts:      /var/run/secrets/kubernetes.io/serviceaccount from default-token-5qwmc (ro)

4、查看容器内存资源的使用情况，分配256M内存，最大可使用为512Mi，利用率为50%，此时没有超过limits限制的大小，容器运行正常

5、当容器内部超过内存的大小会怎么样呢，我们将--vm-byte设置为513M，容器会尝试运行，超过内存后会OOM，kube-controller-manager会不停的尝试重启容器,RESTARTS的次数会不停的增加。

[root@node-1 demo]# cat memory-demo.yaml apiVersion: v1kind: Podmetadata:  name: memory-stress-demo  annotations:    kubernetes.io/description: "stress demo for memory limits"spec:  containers:  - name: memory-stress-limits    image: polinux/stress    resources:      requests:        memory: 128Mi      limits:        memory: 512Mi    command: ["stress"]    args: ["--vm", "1", "--vm-bytes", "520M", "--vm-hang", "1"] . #容器中使用内存为520M查看容器的状态为OOMKilled，RESTARTS的次数不断的增加，不停的尝试重启[root@node-1 demo]# kubectl get pods memory-stress-demo NAME                 READY   STATUS      RESTARTS   AGEmemory-stress-demo   0/1     OOMKilled   3          60s

2. Pod服务质量

服务质量QOS（Quality of Service）主要用于pod调度和驱逐时参考的重要因素，不同的QOS其服务质量不同，对应不同的优先级，主要分为三种类型的Qos：

BestEffort 尽最大努力分配资源，默认没有指定resource分配的Qos，优先级最低；
Burstable 可波动的资源，至少需要分配到requests中的资源，常见的QOS；
Guaranteed 完全可保障资源，requests和limits定义的资源相同，优先级最高。

2.1 BestEffort最大努力

1、Pod中没有定义resource，默认的Qos策略为BestEffort,优先级别最低，当资源比较进展是需要驱逐evice时，优先驱逐BestEffort定义的Pod，如下定义一个BestEffort的Pod

[root@node-1 demo]# cat nginx-qos-besteffort.yaml apiVersion: v1kind: Podmetadata:  name: nginx-qos-besteffort  labels:    name: nginx-qos-besteffortspec:  containers:  - name: nginx-qos-besteffort    image: nginx:1.7.9    imagePullPolicy: IfNotPresent    ports:    - name: nginx-port-80      protocol: TCP      containerPort: 80    resources: {}

2、创建pod并查看Qos策略，qosClass为BestEffort

[root@node-1 demo]# kubectl apply -f nginx-qos-besteffort.yaml pod/nginx-qos-besteffort created查看Qos策略[root@node-1 demo]# kubectl get pods nginx-qos-besteffort -o yamlapiVersion: v1kind: Podmetadata:  annotations:    kubectl.kubernetes.io/last-applied-configuration: |      {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"labels":{"name":"nginx-qos-besteffort"},"name":"nginx-qos-besteffort","namespace":"default"},"spec":{"containers":[{"image":"nginx:1.7.9","imagePullPolicy":"IfNotPresent","name":"nginx-qos-besteffort","ports":[{"containerPort":80,"name":"nginx-port-80","protocol":"TCP"}],"resources":{}}]}}  creationTimestamp: "2019-09-28T11:12:03Z"  labels:    name: nginx-qos-besteffort  name: nginx-qos-besteffort  namespace: default  resourceVersion: "1802411"  selfLink: /api/v1/namespaces/default/pods/nginx-qos-besteffort  uid: 56e4a2d5-8645-485d-9362-fe76aad76e74spec:  containers:  - image: nginx:1.7.9    imagePullPolicy: IfNotPresent    name: nginx-qos-besteffort    ports:    - containerPort: 80      name: nginx-port-80      protocol: TCP    resources: {}    terminationMessagePath: /dev/termination-log...省略...status:  hostIP: 10.254.100.102  phase: Running  podIP: 10.244.1.21  qosClass: BestEffort  #Qos策略  startTime: "2019-09-28T11:12:03Z"

3、删除测试Pod

[root@node-1 demo]# kubectl delete pods nginx-qos-besteffort pod "nginx-qos-besteffort" deleted

2.2 Burstable可波动

1、Pod的服务质量为Burstable，仅次于Guaranteed的服务质量，至少需要一个container定义了requests，且requests定义的资源小于limits资源

[root@node-1 demo]# cat nginx-qos-burstable.yaml apiVersion: v1kind: Podmetadata:  name: nginx-qos-burstable  labels:    name: nginx-qos-burstablespec:  containers:  - name: nginx-qos-burstable    image: nginx:1.7.9    imagePullPolicy: IfNotPresent    ports:    - name: nginx-port-80      protocol: TCP      containerPort: 80    resources:       requests:        cpu: 100m        memory: 128Mi      limits:        cpu: 200m        memory: 256Mi

2、应用yaml文件生成pod并查看Qos类型

[root@node-1 demo]# kubectl apply -f nginx-qos-burstable.yaml pod/nginx-qos-burstable created查看Qos类型[root@node-1 demo]# kubectl describe pods nginx-qos-burstable Name:         nginx-qos-burstableNamespace:    defaultPriority:     0Node:         node-2/10.254.100.102Start Time:   Sat, 28 Sep 2019 19:27:37 +0800Labels:       name=nginx-qos-burstableAnnotations:  kubectl.kubernetes.io/last-applied-configuration:                {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"labels":{"name":"nginx-qos-burstable"},"name":"nginx-qos-burstable","namespa...Status:       RunningIP:           10.244.1.22Containers:  nginx-qos-burstable:    Container ID:   docker://d1324b3953ba6e572bfc63244d4040fee047ed70138b5a4bad033899e818562f    Image:          nginx:1.7.9    Image ID:       docker-pullable://nginx@sha256:e3456c851a152494c3e4ff5fcc26f240206abac0c9d794affb40e0714846c451    Port:           80/TCP    Host Port:      0/TCP    State:          Running      Started:      Sat, 28 Sep 2019 19:27:39 +0800    Ready:          True    Restart Count:  0    Limits:      cpu:     200m      memory:  256Mi    Requests:      cpu:        100m      memory:     128Mi    Environment:      Mounts:      /var/run/secrets/kubernetes.io/serviceaccount from default-token-5qwmc (ro)Conditions:  Type              Status  Initialized       True   Ready             True   ContainersReady   True   PodScheduled      True Volumes:  default-token-5qwmc:    Type:        Secret (a volume populated by a Secret)    SecretName:  default-token-5qwmc    Optional:    falseQoS Class:       Burstable  #服务质量是可波动的BurstableNode-Selectors:  Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s                 node.kubernetes.io/unreachable:NoExecute for 300sEvents:  Type    Reason     Age   From               Message  ----    ------     ----  ----               -------  Normal  Scheduled  95s   default-scheduler  Successfully assigned default/nginx-qos-burstable to node-2  Normal  Pulled     94s   kubelet, node-2    Container image "nginx:1.7.9" already present on machine  Normal  Created    94s   kubelet, node-2    Created container nginx-qos-burstable  Normal  Started    93s   kubelet, node-2    Started container nginx-qos-burstable

2.3 Guaranteed完全保障

1、resource中定义的cpu和memory必须包含有requests和limits，切requests和limits的值必须相同，其优先级别最高，当出现调度和驱逐时优先保障该类型的Qos,如下定义一个nginx-qos-guaranteed的容器，requests.cpu和limits.cpu相同，同理requests.memory和limits.memory.

[root@node-1 demo]# cat nginx-qos-guaranteed.yaml apiVersion: v1kind: Podmetadata:  name: nginx-qos-guaranteed  labels:    name: nginx-qos-guaranteedspec:  containers:  - name: nginx-qos-guaranteed    image: nginx:1.7.9    imagePullPolicy: IfNotPresent    ports:    - name: nginx-port-80      protocol: TCP      containerPort: 80    resources:       requests:        cpu: 200m        memory: 256Mi      limits:        cpu: 200m        memory: 256Mi

2、应用yaml文件生成pod并查看pod的Qos类型为可完全保障Guaranteed

[root@node-1 demo]# kubectl apply -f nginx-qos-guaranteed.yaml pod/nginx-qos-guaranteed created[root@node-1 demo]# kubectl describe pods nginx-qos-guaranteed Name:         nginx-qos-guaranteedNamespace:    defaultPriority:     0Node:         node-2/10.254.100.102Start Time:   Sat, 28 Sep 2019 19:37:15 +0800Labels:       name=nginx-qos-guaranteedAnnotations:  kubectl.kubernetes.io/last-applied-configuration:                {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"labels":{"name":"nginx-qos-guaranteed"},"name":"nginx-qos-guaranteed","names...Status:       RunningIP:           10.244.1.23Containers:  nginx-qos-guaranteed:    Container ID:   docker://cf533e0e331f49db4e9effb0fbb9249834721f8dba369d281c8047542b9f032c    Image:          nginx:1.7.9    Image ID:       docker-pullable://nginx@sha256:e3456c851a152494c3e4ff5fcc26f240206abac0c9d794affb40e0714846c451    Port:           80/TCP    Host Port:      0/TCP    State:          Running      Started:      Sat, 28 Sep 2019 19:37:16 +0800    Ready:          True    Restart Count:  0    Limits:      cpu:     200m      memory:  256Mi    Requests:      cpu:        200m      memory:     256Mi    Environment:      Mounts:      /var/run/secrets/kubernetes.io/serviceaccount from default-token-5qwmc (ro)Conditions:  Type              Status  Initialized       True   Ready             True   ContainersReady   True   PodScheduled      True Volumes:  default-token-5qwmc:    Type:        Secret (a volume populated by a Secret)    SecretName:  default-token-5qwmc    Optional:    falseQoS Class:       Guaranteed #服务质量为可完全保障GuaranteedNode-Selectors:  Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s                 node.kubernetes.io/unreachable:NoExecute for 300sEvents:  Type    Reason     Age   From               Message  ----    ------     ----  ----               -------  Normal  Scheduled  25s   default-scheduler  Successfully assigned default/nginx-qos-guaranteed to node-2  Normal  Pulled     24s   kubelet, node-2    Container image "nginx:1.7.9" already present on machine  Normal  Created    24s   kubelet, node-2    Created container nginx-qos-guaranteed  Normal  Started    24s   kubelet, node-2    Started container nginx-qos-guaranteed

写在最后

本章是kubernetes系列教程第六篇文章，通过介绍resource资源的分配和服务质量Qos，关于resource有节点使用建议：

requests和limits资源定义推荐不超过1:2，避免分配过多资源而出现资源争抢，发生OOM；
pod中默认没有定义resource，推荐给namespace定义一个limitrange，确保pod能分到资源；
防止node上资源过度而出现机器hang住或者OOM，建议node上设置保留和驱逐资源，如保留资源--system-reserved=cpu=200m,memory=1G，驱逐条件--eviction hard=memory.available<500Mi。