CKA 相关信息和资料总结

作者: Kii_la | 来源:发表于2019-08-28 19:24 被阅读0次

简书的 Markdown 渲染有点问题, https://blog.kii.la/post/kubernetes/tattle/cka-相关信息和资料总结/

考试注意事项

考试前 15 分钟进入考试界面. 涉及确认身份可以带护照. 检查周围环境.桌面环境以及提示注意事项.全程全英文对话沟通.
进入考题,考题是中文显示,有些翻译不是很好,建议打开英文版查看.
建议找个好一点的网络考试,可以选择使用 VPN 或者公司网络.
如果考试中断,新建 Tab 页申请进入.
Chrome 浏览器.
考试时间比较紧张.建议对于比较难的题目暂时放下,记录在提供的 note 表里, 做完简单的再功课.
对于 Kubernetes.io 的内容是可以直接拷贝粘贴的.
节省时间的技巧:
1. 尽量使用 kubectl run 命令
2. 可以将相关的内容保存标签,方便快速打开.
3. CLI 的 -h 求助
4. 尽量使用简写,例如 Namespace - ns 等.
5. source < (kubectl completion bash) 命令补全.

Scheduling [调度] 5%

Exam1: 创建一个运行 60 次,同时运行 2 个作业的 Job

参考链接 [Jobs - Run to Completion] (https://git.kii.la/Kiila/kubernetes-document/blob/master/Concepts/Controller/Jobs%20-%20Run%20to%20Completion.md#jobs-run-to-completion)

apiVersion: batch/v1
kind: Job
metadata:
    name: sixty-times-job
spec:
    completions: 60
    parallelism: 2
    template:
        spec:
            containers:
                - name: sixty-times-job
                  image: perl
                  command:
                    - perl
                    - -Mbigmum=bpi
                    - -wle
                    - print bpi(2000)
            restartPolicy: Never

</details>

Exam: 设置现有名为 `myjob` 的 Job 的副本数为 10.

$ kubectl scale --replicas=10 jobs/myjob
job "myjob" scalled

注意:

parallelism : 并行执行的数量.
completions: 运行 job 成功的次数
RestartPolicy: 仅支持 Never 或 OnFailure
activeDeadlineSeconds: 如果 Pod 失败时, 重试最大时间, 超过这个时间就不会继续重试.
</details>

Exam: Static Pod

在指定位置创建 Pod 清单, 然后编辑用于 kubelet (/etc/systemd/system/kubelet.service) 的 systemd 服务文件, 包含 --pod-manifest-path=/specified/path. 一旦完成, 重新启动服务.

Choose a node where we want to run the static pod. In this example, it’s my-node1.

[joe@host ~] $ ssh my-node1
Choose a directory, say /etc/kubelet.d and place a web server pod definition there, e.g. /etc/kubelet.d/static-pod.yaml:

[root@my-node1 ~] $ mkdir /etc/kubernetes.d/ 
[root@my-node1 ~] $ cat <<EOF >/etc/kubernetes.d/static-pod.yaml 
apiVersion: v1
kind: Pod
metadata:
    name: static-pod
spec:
    containers:
    - image: busybox
    name: test-container
    command: ["/bin/sh", "-c", "sleep 9999"]
EOF
Configure your kubelet daemon on the node to use this directory by running it with --pod-manifest-path=/etc/kubelet.d/ argument. On Fedora edit /etc/kubernetes/kubelet to include this line:

KUBELET_ARGS="--cluster-dns=10.254.0.10 --cluster-domain=kube.local --pod-manifest-path=/etc/kubelet.d/"
Instructions for other distributions or Kubernetes installations may vary. Restart kubelet. On Fedora, this is:

[root@my-node1 ~] $ systemctl restart kubelet

效果如下：

[root@dev-9 manifests]# kubectl get pod
NAME                                      READY     STATUS        RESTARTS   AGE
static-pod-dev-9                          1/1       Running       0          34s
[root@dev-9 manifests]#
[root@dev-9 manifests]# kubectl describe pod static-pod-dev-9
Name:                static-pod-dev-9
Namespace:        default
Node:                dev-9/192.168.1.190
Start Time:        Sun, 12 Nov 2017 21:21:48 +0800
Labels:                <none>
Annotations:        kubernetes.io/config.hash=1dcad4affd910f45b5c3a8dbdeec8933
                kubernetes.io/config.mirror=1dcad4affd910f45b5c3a8dbdeec8933
                kubernetes.io/config.seen=2017-11-12T21:21:48.15196949+08:00
                kubernetes.io/config.source=file
Status:                Running
IP:                10.244.3.45
Containers:
    test-container:
    Container ID:        docker://ef3e28e45e280e4a50942fc472fd025cb84a7014a64dbc57308cddbfeb1bd979
    Image:                busybox
    Image ID:                docker-pullable://busybox@sha256:bbc3a03235220b170ba48a157dd097dd1379299370e1ed99ce976df0355d24f0
    Port:                <none>
    Command:
        /bin/sh
        -c
        sleep 9999
    State:                Running
        Started:                Sun, 12 Nov 2017 21:21:52 +0800
    Ready:                True
    Restart Count:        0
    Environment:        <none>
    Mounts:                <none>
Conditions:
    Type                Status
    Initialized         True
    Ready         True
    PodScheduled         True
Volumes:        <none>
QoS Class:        BestEffort
Node-Selectors:        <none>
Tolerations:        :NoExecute
Events:                <none>
[root@dev-9 manifests]#

</details>

Exam: 仅在指定节点上运行 `Jenkins Pod`

Logging / Monitoring [日志 / 监控] 5%

Exam: 找到使用 `CPU` 资源最多的 Pod

kubectl top pod sort-by=.spec.capacity.xxx

kubectl top pod | awk '{print $1 "\t" $3 | "sort -r -n"}'

</details>

Exam: 找到带有字符串 `Some-error message here` 的错误信息

https://kubernetes.io/docs/concepts/cluster-administration/logging/
see kubectl logs and /var/log for system services

Application Lifecycle Management [应用程序生命周期管理] 8%

Cluster [集群] 11%

Exam: 按名字排序列出所有 PresistenteVolumes

kubectl get pv sort-by=.metadata.name

</details>

Exam: 使用应用程序 `nslookup` 查找 `service` 和 `pod` 的 DNS 记录

https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/

<details>
<summary>Services</summary>

$ kubectl exec -ti busybox -- nslookup mysvc.myns.svc.cluster.local
Naming conventions for services and pods:

For a regular service, this resolves to the port number and the CNAME: (解析到Cluster-IP)
my-svc.my-namespace.svc.cluster.local.
root@test-9:~/henry# kubectl exec -ti busybox-2520568787-kkmrw -- nslookup nginx.default.svc.cluster.local
Server:    10.43.0.10
Address 1: 10.43.0.10 kube-dns.kube-system.svc.cluster.local

Name:      nginx.default
Address 1: 10.43.120.19 nginx.default.svc.cluster.local
root@test-9:~/henry#
For a headless service, this resolves to multiple answers（RR解析到多个Pod IP), one for each pod that is backing the service, and contains the port number and a CNAME of the pod of the form
auto-generated-name.my-svc.my-namespace.svc.cluster.local

</details>

When enabled, pods are assigned a DNS A record in the form of

pod-ip-address.my-namespace.pod.cluster.local
For example, a pod with IP 1.2.3.4 in the namespace default with a DNS name of cluster.local would have an entry: 1-2-3-4.default.pod.cluster.local

root@test-9:~/henry# kubectl exec -ti busybox-2520568787-kkmrw -- nslookup 10-42-236-215.default.pod.cluster.local
Server:    10.43.0.10
Address 1: 10.43.0.10 kube-dns.kube-system.svc.cluster.local

Name:      10-42-236-215.default.pod.cluster.local
Address 1: 10.42.236.215

</details>

Exame: 对deployment做rollingUpdate，再滚回来

RollingUpdate (貌似对于deploy限制只能够设置其image、resource、selector、subject来实现)
[root@dev-7 henry]# kubectl run demo --image=nginx --port=80 --replicas=2 --labels="cka=true"
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl get deploy
NAME                     DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
demo                     2         2         2            2           4m
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl get pod -l cka=true
NAME                    READY     STATUS    RESTARTS   AGE
demo-2959463917-gbv3r   1/1       Running   0          1m
demo-2959463917-j76m9   1/1       Running   0          1m
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl set --help
Configure application resources

These commands help you make changes to existing application resources.

Available Commands:
    image       Update image of a pod template
    resources   Update resource requests/limits on objects with pod templates
    selector    Set the selector on a resource
    subject     Update User, Group or ServiceAccount in a RoleBinding/ClusterRoleBinding
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl set image deploy/demo demo=mysql
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl rollout history deploy/demo
deployments "demo"
REVISION        CHANGE-CAUSE
1                <none>
2                <none>
[root@dev-7 henry]# kubectl rollout history deploy/demo --revison=2
deployments "demo" with revision #2
Pod Template:
    Labels:        cka=true
        pod-template-hash=2216264665
    Containers:
    demo:
    Image:        mysql
    Port:        80/TCP
    Environment:        <none>
    Mounts:        <none>
    Volumes:        <none>

[root@dev-7 henry]#
[root@dev-7 henry]# kubectl rollout undo deploy/demo
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl rollout history deploy/demo
deployments "demo"
REVISION        CHANGE-CAUSE
2                <none>
3                <none>
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl rollout history deploy/demo --revision=3
deployments "demo" with revision #3
Pod Template:
    Labels:        cka=true
        pod-template-hash=1786957899
    Containers:
    demo:
    Image:        nginx
    Port:        80/TCP
    Environment:        <none>
    Mounts:        <none>
    Volumes:        <none>

[root@dev-7 henry]#
[root@dev-7 henry]# kubectl rollout undo deploy/demo --to-revision=2
一种较保守的做法是先将其锁住，等待操作完成，检查OK了再下发：

[root@dev-7 henry]# kubectl rollout pause deploy/demo
deployment "demo" paused
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl set image deploy/demo demo=busybox
deployment "demo" image updated
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl set resources deploy/demo -c=demo --limits=cpu=200m,memory=512Mi
deployment "demo" resource requirements updated
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl rollout resume deploy/demo
deployment "demo" resumed
[root@dev-7 henry]#
除此之外，rollingUpdate还可以通过kubectl apply来实现：

[root@dev-7 henry]# kubectl apply -f demo.yaml --record
deployment "demo" configured
[root@dev-7 henry]#
[root@dev-7 henry]# kubectl rollout history deploy/demo
deployments "demo"
REVISION        CHANGE-CAUSE
4                <none>
5                <none>
6                <none>
7                <none>
8                kubectl apply --filename=demo.yaml --record=true
[root@dev-7 henry]#
自动弹性伸缩：

[root@dev-7 henry]# kubectl autoscale deploy/demo --min=10 --max=15 --cpu-percent=80
deployment "demo" autoscaled
Hook

Pod支持两种hook：

postStart 在pod启动成功了后调用
preStop 在pod停止之前调用
支持两种hook handler：

Exec
HTTP
apiVersion: v1
kind: Pod
metadata:
    name: lifecycle-demo
spec:
    containers:
    - name: lifecycle-demo-container
    image: nginx

    lifecycle:
        postStart:
        exec:
            command: ["/bin/sh", "-c", "echo Hello from the postStart handler > /usr/share/message"]
        preStop:
        exec:
            command: ["/usr/sbin/nginx","-s","quit"]
kubectl taint

</details>

Exam: ENV

Use Pod Field

root@test-9:~# kubectl get deploy -o yaml | grep env -C 10
        maxSurge: 1
        maxUnavailable: 1
        type: RollingUpdate
    template:
        metadata:
        creationTimestamp: null
        labels:
            demo: "true"
        spec:
        containers:
        - env:
            - name: MY_NODE_NAME
            valueFrom:
                fieldRef:
                apiVersion: v1
                fieldPath: spec.nodeName
            - name: SECRET_USER
            valueFrom:
                secretKeyRef:
                key: user
                name: demo
root@test-9:~#
root@test-9:~# kubectl exec -ti nginx-f7d4dc847-skb74 /bin/bash
root@nginx-f7d4dc847-skb74:/# env | grep MY_NODE
MY_NODE_NAME=test-10
root@nginx-f7d4dc847-skb74:/#
Use Container Filed
apiVersion: v1
kind: Pod
metadata:
    name: dapi-envars-resourcefieldref
spec:
    containers:
    - name: test-container
        image: gcr.io/google_containers/busybox:1.24
        command: [ "sh", "-c"]
        args:
        - while true; do
            echo -en '\n';
            printenv MY_CPU_REQUEST MY_CPU_LIMIT;
            printenv MY_MEM_REQUEST MY_MEM_LIMIT;
            sleep 10;
        done;
        resources:
        requests:
            memory: "32Mi"
            cpu: "125m"
        limits:
            memory: "64Mi"
            cpu: "250m"
        env:
        - name: MY_CPU_REQUEST
            valueFrom:
            resourceFieldRef:
                containerName: test-container
                resource: requests.cpu
        - name: MY_CPU_LIMIT
            valueFrom:
            resourceFieldRef:
                containerName: test-container
                resource: limits.cpu
    restartPolicy: Never

</details>

Exam: 对node做taint (taint a node)

注意：
taint指定的 key:value 与node的label之间没有任何关系！
在添加taint的时候，需要指定: key=value:effect
在删除taint的时候，不需要指定 value，格式为: key:effect
<details>
<summary>show code</summary>

root@test-9:~# kubectl get pod -o wide
NAME                     READY     STATUS    RESTARTS   AGE       IP            NODE
nginx-5b444f5b58-dpvzq   1/1       Running   0          2m        10.244.0.7    test-9
nginx-5b444f5b58-k6qxp   1/1       Running   0          2m        10.244.0.8    test-9
nginx-5b444f5b58-n7prf   1/1       Running   0          2m        10.244.0.9    test-9
nginx-5b444f5b58-r4265   1/1       Running   0          2m        10.244.0.11   test-9
nginx-5b444f5b58-rs2hn   1/1       Running   0          2m        10.244.0.10   test-9
nginx-5b444f5b58-v6r2x   1/1       Running   0          2m        10.244.0.6    test-9
root@test-9:~#
root@test-9:~# kubectl taint node test-9 taint=true:NoExecute
node "test-9" tainted
root@test-9:~#
root@test-9:~# kubectl describe node test-9
Name:               test-9
Roles:              master
Labels:             beta.kubernetes.io/arch=amd64
                    beta.kubernetes.io/os=linux
                    kubernetes.io/hostname=test-9
                    node-role.kubernetes.io/master=
Annotations:        flannel.alpha.coreos.com/backend-data={"VtepMAC":"9a:e5:cf:c9:fb:79"}
                    flannel.alpha.coreos.com/backend-type=vxlan
                    flannel.alpha.coreos.com/kube-subnet-manager=true
                    flannel.alpha.coreos.com/public-ip=10.144.96.185
                    node.alpha.kubernetes.io/ttl=0
                    volumes.kubernetes.io/controller-managed-attach-detach=true
Taints:             taint=true:NoExecute
CreationTimestamp:  Mon, 13 Nov 2017 20:56:37 +0800
root@test-9:~#
root@test-9:~# kubectl get pod -o wide
NAME                     READY     STATUS    RESTARTS   AGE       IP            NODE
nginx-5b444f5b58-2s5dw   1/1       Running   0          28s       10.244.1.24   test-10
nginx-5b444f5b58-b6pds   1/1       Running   0          28s       10.244.1.23   test-10
nginx-5b444f5b58-cg75j   1/1       Running   0          28s       10.244.1.21   test-10
nginx-5b444f5b58-d8nbl   1/1       Running   0          28s       10.244.1.20   test-10
nginx-5b444f5b58-pncbm   1/1       Running   0          28s       10.244.1.18   test-10
nginx-5b444f5b58-zbc4h   1/1       Running   0          28s       10.244.1.22   test-10
root@test-9:~#
root@test-9:~# kubectl taint node test-9 taint:NoExecute-
node "test-9" untainted
root@test-9:~#
Effect支持：
NoSchedule/NoExecute/PreferNoSchedule
kubectl taint nodes node1 key1=value1:NoSchedule
kubectl taint nodes node1 key1=value1:NoExecute
kubectl taint nodes node1 key2=value2:NoSchedule

</details>

Tolerations支持：

指定匹配 key/value和effect
tolerations:

key: “key”
operator: “Equal”
value: “value”
effect: “NoSchedule”
指定 key存在且指定effect
tolerations:

key: “key”
operator: “Exists”
effect: “NoSchedule”
只要有任何key存在
tolerations:

operator: “Exists”
指定key存在
tolerations:

key: “key”
operator: “Exists”
代表往node添加taint后，多长时间之内，该pod依然可以存活（时间结束后，将被删除）
tolerations:

key: “key1”
operator: “Equal”
value: “value1”
effect: “NoExecute”
tolerationSeconds: 3600
例子：

root@test-9:~# kubectl get pod -o wide
NAME                     READY     STATUS    RESTARTS   AGE       IP            NODE
nginx-5b444f5b58-2s5dw   1/1       Running   0          16m       10.244.1.24   test-10
nginx-5b444f5b58-b6pds   1/1       Running   0          16m       10.244.1.23   test-10
nginx-5b444f5b58-cg75j   1/1       Running   0          16m       10.244.1.21   test-10
nginx-5b444f5b58-d8nbl   1/1       Running   0          16m       10.244.1.20   test-10
nginx-5b444f5b58-pncbm   1/1       Running   0          16m       10.244.1.18   test-10
nginx-5b444f5b58-zbc4h   1/1       Running   0          16m       10.244.1.22   test-10
root@test-9:~#
root@test-9:~# kubectl taint node test-9 taint=true:NoExecute
node "test-9" tainted
root@test-9:~#
root@test-9:~# kubectl edit deploy nginx
deployment "nginx" edited
root@test-9:~#
root@test-9:~# kubectl get pod -o wide
NAME                    READY     STATUS    RESTARTS   AGE       IP            NODE
nginx-9bf4c9c69-27r6m   1/1       Running   0          17s       10.244.1.26   test-10
nginx-9bf4c9c69-cnjk2   1/1       Running   0          23s       10.244.0.12   test-9
nginx-9bf4c9c69-fttrd   1/1       Running   0          23s       10.244.1.25   test-10
nginx-9bf4c9c69-jw7w2   1/1       Running   0          11s       10.244.1.27   test-10
nginx-9bf4c9c69-s57h2   1/1       Running   0          12s       10.244.0.14   test-9
nginx-9bf4c9c69-z8jrn   1/1       Running   0          18s       10.244.0.13   test-9
root@test-9:~#
root@test-9:~# kubectl get deploy nginx -o yaml | grep tolerations -C 5
        dnsPolicy: ClusterFirst
        restartPolicy: Always
        schedulerName: default-scheduler
        securityContext: {}
        terminationGracePeriodSeconds: 30
        tolerations:
        - operator: Exists
status:
    availableReplicas: 6
    conditions:
    - lastTransitionTime: 2017-11-13T13:23:03Z
root@test-9:~#
Secret
generic
root@test-9:~# kubectl create secret generic demo --from-literal=user=chenleji --from-literal=passwd=123
secret "demo" created
root@test-9:~#
root@test-9:~# kubectl get secret
NAME                  TYPE                                  DATA      AGE
default-token-wgrhs   kubernetes.io/service-account-token   3         1h
demo                  Opaque                                2         4s
root@test-9:~#
root@test-9:~# kubectl get secret demo -o yaml
apiVersion: v1
data:
    passwd: MTIz
    user: Y2hlbmxlamk=
kind: Secret
metadata:
    creationTimestamp: 2017-11-13T14:12:00Z
    name: demo
    namespace: default
    resourceVersion: "7108"
    selfLink: /api/v1/namespaces/default/secrets/demo
    uid: 9da9b9f4-c87c-11e7-9401-525400545760
type: Opaque
root@test-9:~#
root@test-9:~# echo -n MTIz | base64 --decode
123
root@test-9:~# echo -n Y2hlbmxlamk= | base64 --decode
chenleji
root@test-9:~#
root@test-9:~#

</details>

Storage [存储] 7%

Exam: 您有一个带有挂载卷的容器. 添加一个在卷中创建空文件的 `InitContainer`.

https://kubernetes.io/docs/concepts/workloads/pods/init-containers/

Exam: Redis 数据存储的问题

在预生产环境中运行 redis 键值对存储时, 许多部署都来自于 CI, 并在 Redis 中留下了大量陈旧的缓存数据, 这将导致测试失败.
CI 管理员要求, 在每次的 staging 中部署 Redis 键值对存储时, 它都不应该被持久化其数据. 创建一个名为 non-persistent-redis 的 pod, 它指定一个名为 app-cache 的卷, 以及挂载路径 /data/redis. 它应该在 staging 命名空间中启动,并且卷不能是持久性的. 创建一个带有 EmptyDir 的 Pod, 并在 YAML 文件中添加命名空间 CI.

Exam: TLS

kubectl create secret tls tls-secret --cert=path/to/tls.cert --key=path/to/tls.key
Registry

kubectl create secret docker-registry my-secret --docker-server=DOCKER_REGISTRY_SERVER
--docker-username=DOCKER_USER --docker-password=DOCKER_PASSWORD --docker-email=DOCKER_EMAIL
volume mount

未指定挂载的具体文件名：

root@test-9:~# kubectl get deploy -o yaml | grep volume -C 5
            imagePullPolicy: Always
            name: nginx
            resources: {}
            terminationMessagePath: /dev/termination-log
            terminationMessagePolicy: File
            volumeMounts:
            - mountPath: /secret
            name: secret
        dnsPolicy: ClusterFirst
        restartPolicy: Always
        schedulerName: default-scheduler
        securityContext: {}
        terminationGracePeriodSeconds: 30
        tolerations:
        - operator: Exists
        volumes:
        - name: secret
            secret:
            defaultMode: 420
            secretName: demo
    status:
root@test-9:~#
root@test-9:~# kubectl exec -ti nginx-557769d5c5-45sdq /bin/bash
root@nginx-557769d5c5-45sdq:/# ls -l /secret/
total 0
lrwxrwxrwx 1 root root 13 Nov 13 14:23 passwd -> ..data/passwd
lrwxrwxrwx 1 root root 11 Nov 13 14:23 user -> ..data/user
root@nginx-557769d5c5-45sdq:/#
root@nginx-557769d5c5-45sdq:/# cat /secret/passwd
123
root@nginx-557769d5c5-45sdq:/#
指定挂载文件名：

root@test-9:~# kubectl describe secret demo
Name:         demo
Namespace:    default
Labels:       <none>
Annotations:  <none>
Type:  Opaque
Data
====
passwd:  3 bytes
user:    8 bytes
root@test-9:~#
root@test-9:~# kubectl get deploy nginx -o yaml | grep volume -C 8
    spec:
        containers:
        - image: nginx
        imagePullPolicy: Always
        name: nginx
        resources: {}
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
        volumeMounts:
        - mountPath: /secret
            name: secret
        dnsPolicy: ClusterFirst
        restartPolicy: Always
        schedulerName: default-scheduler
        securityContext: {}
        terminationGracePeriodSeconds: 30
        tolerations:
        - operator: Exists
        volumes:
        - name: secret
        secret:
            defaultMode: 420
            items:
            - key: user
            path: haha/xx
            secretName: demo
status:
root@test-9:~#
root@nginx-657c6dcd4c-56p5h:/# cat /secret/haha/xx
chenleji
root@nginx-657c6dcd4c-56p5h:/#
env
root@test-9:~# kubectl get deploy nginx -o yaml | grep env -C 6
    metadata:
        creationTimestamp: null
        labels:
        demo: "true"
    spec:
        containers:
        - env:
        - name: SECRET_USER
            valueFrom:
            secretKeyRef:
                key: user
                name: demo
        image: nginx
root@test-9:~#
root@test-9:~# kubectl exec -ti nginx-548c9c4846-dgnbk /bin/bash
root@nginx-548c9c4846-dgnbk:/# env | grep SECRET
SECRET_USER=chenleji
root@nginx-548c9c4846-dgnbk:/#

</details>

Networking [网络] 11%

Exam: 创建一个网络策略，只允许通过busybox pod连接到端口8080

# kubectl annotate ns default "net.beta.kubernetes.io/network-policy={\"ingress\": {\"isolation\": \"DefaultDeny\"}}"
namespace "default" annotated
# kubectl describe ns default
Name:         default
Labels:       <none>
Annotations:  net.beta.kubernetes.io/network-policy={"ingress": {"isolation": "DefaultDeny"}}
Status:       Active
No resource quota.
No resource limits.
#
# kubectl get pod --show-labels
NAME                      READY     STATUS    RESTARTS   AGE       LABELS
nginx2-2627548522-6f5kf   1/1       Running   0          22m       pod-template-hash=2627548522,run=nginx
nginx2-2627548522-8w87b   1/1       Running   0          22m       pod-template-hash=2627548522,run=nginx
# kubectl get svc nginx --show-labels
NAME      TYPE       CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE       LABELS
nginx     NodePort   10.43.120.19   <none>        80:30014/TCP   16m       run=nginx
# cat network-policy.yaml
kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
    name: access-nginx
spec:
    podSelector:
    matchLabels:
        run: nginx
    ingress:
    - from:
    - namespaceSelector:
        matchLabels:
            project: myproject
    - podSelector:
        matchLabels:
            access: "true"
    ports:
    - protocol: TCP
        port: 80
# kubectl get netpol
NAME           POD-SELECTOR   AGE
access-nginx   run=nginx      2m
# kubectl get netpol access-nginx -o yaml
apiVersion: extensions/v1beta1
kind: NetworkPolicy
metadata:
    creationTimestamp: 2017-11-12T07:40:38Z
    generation: 1
    name: access-nginx
    namespace: default
    resourceVersion: "20699"
    selfLink: /apis/extensions/v1beta1/namespaces/default/networkpolicies/access-nginx
    uid: c72191d1-c77c-11e7-8dee-02cdc7a8bd69
spec:
    ingress:
    - from:
    - podSelector:
        matchLabels:
            access: "true"
        ports:
        - port: 80
        protocol: TCP
    podSelector:
    matchLabels:
        run: nginx
#
# kubectl run busybox --rm -ti --labels="access=true" --image=busybox /bin/sh
If you don't see a command prompt, try pressing enter.
/ # wget nginx
Connecting to nginx (10.43.120.19:80)
index.html           100% |********************************************************************************************|   612   0:00:00 ETA
/ #

Exam : 创建一个 Ingress 资源, Ingress 控制器以及一个 Service 解析 `cs.rocks.ch` 的服务.

First, create controller and default backend
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress/master/controllers/nginx/examples/default-backend.yaml
kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress/master/examples/deployment/nginx/nginx-ingress-controller.yaml
Second, create service and expose

kubectl run ingress-pod --image=nginx --port 80
kubectl expose deployment ingress-pod --port=80 --target-port=80 --type=NodePort
Create the ingress

cat <<EOF >ingress-cka.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
    name: ingress-service
spec:
    rules:
    - host: "cs.rocks.ch"
    http:
        paths:
        - backend:
            serviceName: ingress-pod
            servicePort: 80
EOF
To test, run a curl pod

kubectl run -i --tty client --image=tutum/curl
curl -I -L --resolve cs.rocks.ch:80:10.240.0.5 http://cs.rocks.ch/
我认为，要访问ingress，在flannel网络中，应该还可以使用hostPort来暴露出ingress-nginx的80和443端口。

Mandatory commands

curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/namespace.yaml | kubectl apply -f -

curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/default-backend.yaml | kubectl apply -f -

curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/configmap.yaml | kubectl apply -f -

curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/tcp-services-configmap.yaml  | kubectl apply -f -

curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/udp-services-configmap.yaml | kubectl apply -f -
Install with RBAC roles

curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/rbac.yaml | kubectl apply -f -

curl https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/with-rbac.yaml | kubectl apply -f -
Verify installation:

kubectl get pods --all-namespaces -l app=ingress-nginx --watch

</details>

Installation, Configuration & Validation [安装, 配置以及验证] 12%

Exam: `etcd` 备份和快照

https://kubernetes.io/docs/getting-started-guides/ubuntu/backups/
https://www.mirantis.com/blog/everything-you-ever-wanted-to-know-about-using-etcd-with-kubernetes-v1-6-but-were-afraid-to-ask/

Troubleshooting [问题解决] 10%

Exam: 修复损坏的节点

https://kubernetes.io/docs/concepts/architecture/nodes/

CKA 相关信息和资料总结

考试注意事项

Scheduling [调度] 5%

Exam1: 创建一个运行 60 次,同时运行 2 个作业的 Job

Exam: 设置现有名为 `myjob` 的 Job 的副本数为 10.

Exam: Static Pod

Exam: 仅在指定节点上运行 `Jenkins Pod`

Logging / Monitoring [日志 / 监控] 5%

Exam: 找到使用 `CPU` 资源最多的 Pod

Exam: 找到带有字符串 `Some-error message here` 的错误信息

Application Lifecycle Management [应用程序生命周期管理] 8%

Cluster [集群] 11%

Exam: 按名字排序列出所有 PresistenteVolumes

Exam: 使用应用程序 `nslookup` 查找 `service` 和 `pod` 的 DNS 记录

Exame: 对deployment做rollingUpdate，再滚回来

Exam: ENV

Exam: 对node做taint (taint a node)

Storage [存储] 7%

Exam: 您有一个带有挂载卷的容器. 添加一个在卷中创建空文件的 `InitContainer`.

Exam: Redis 数据存储的问题

Exam: TLS

Networking [网络] 11%

Exam: 创建一个网络策略，只允许通过busybox pod连接到端口8080

Exam : 创建一个 Ingress 资源, Ingress 控制器以及一个 Service 解析 `cs.rocks.ch` 的服务.

Installation, Configuration & Validation [安装, 配置以及验证] 12%

Exam: `etcd` 备份和快照

Troubleshooting [问题解决] 10%

Exam: 修复损坏的节点

相关文章

网友评论

延伸阅读

深度阅读

栏目导航

热点阅读

Kubernetes

CKA 相关信息和资料总结

考试注意事项

Scheduling [调度] 5%

Exam1: 创建一个运行 60 次,同时运行 2 个作业的 Job

Exam: 设置现有名为 myjob 的 Job 的副本数为 10.

Exam: Static Pod

Exam: 仅在指定节点上运行 Jenkins Pod

Logging / Monitoring [日志 / 监控] 5%

Exam: 找到使用 CPU 资源最多的 Pod

Exam: 找到带有字符串 Some-error message here 的错误信息

Application Lifecycle Management [应用程序生命周期管理] 8%

Cluster [集群] 11%

Exam: 按名字排序列出所有 PresistenteVolumes

Exam: 使用应用程序 nslookup 查找 service 和 pod 的 DNS 记录

Exame: 对deployment做rollingUpdate，再滚回来

Exam: ENV

Exam: 对node做taint (taint a node)

Storage [存储] 7%

Exam: 您有一个带有挂载卷的容器. 添加一个在卷中创建空文件的 InitContainer.

Exam: Redis 数据存储的问题

Exam: TLS

Networking [网络] 11%

Exam: 创建一个网络策略，只允许通过busybox pod连接到端口8080

Exam : 创建一个 Ingress 资源, Ingress 控制器以及一个 Service 解析 cs.rocks.ch 的服务.

Installation, Configuration & Validation [安装, 配置以及验证] 12%

Exam: etcd 备份和快照

Troubleshooting [问题解决] 10%

Exam: 修复损坏的节点

相关文章

网友评论

延伸阅读

深度阅读

栏目导航

热点阅读

Kubernetes

Exam: 设置现有名为 `myjob` 的 Job 的副本数为 10.

Exam: 仅在指定节点上运行 `Jenkins Pod`

Exam: 找到使用 `CPU` 资源最多的 Pod

Exam: 找到带有字符串 `Some-error message here` 的错误信息

Exam: 使用应用程序 `nslookup` 查找 `service` 和 `pod` 的 DNS 记录

Exam: 您有一个带有挂载卷的容器. 添加一个在卷中创建空文件的 `InitContainer`.

Exam : 创建一个 Ingress 资源, Ingress 控制器以及一个 Service 解析 `cs.rocks.ch` 的服务.

Exam: `etcd` 备份和快照