kubernetes云平台管理实战： 最小的资源pod（二）

时间：2023-12-26 13:53:55

一、pod初体验

1、编辑k8s_pod.yml文件

[root@k8s-master ~]# cat k8s_pod.yml

apiVersion: v1

kind: Pod

metadata:

  name: nginx

  labels:

    app: web

spec:

  containers:

    - name: nginx

      image: 10.0.128.0:5000/nginx:latest

      ports:

        - containerPort: 80

2、下载镜像并上传到私有仓库

[root@k8s-master ~]# docker pull nginx:latest

Trying to pull repository docker.io/library/nginx ...

latest: Pulling from docker.io/library/nginx

177e7ef0df69: Pull complete

ea57c53235df: Pull complete

bbdb1fbd4a86: Pull complete

Digest: sha256:b543f6d0983fbc25b9874e22f4fe257a567111da96fd1d8f1b44315f1236398c

[root@k8s-master ~]# docker tag nginx:latest  10.0.128.0:5000/nginx:latest

[root@k8s-master ~]# docker push 10.0.128.0:5000/nginx:latest

The push refers to a repository [10.0.128.0:5000/nginx]

b7efe781401d: Pushed

c9c2a3696080: Pushed

7b4e562e58dc: Pushed

latest: digest: sha256:e2847e35d4e0e2d459a7696538cbfea42ea2d3b8a1ee8329ba7e68694950afd3 size: 948

3、启动pod

[root@k8s-master ~]# kubectl create -f k8s_pod.yml

pod "nginx" created

[root@k8s-master ~]# docker ps -a

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                         PORTS                    NAMES

e166a705c0a7        busybox             "/bin/sh"                31 minutes ago      Exited (0) 10 minutes ago                               cranky_bardeen

ba8d9b958c7c        registry            "/entrypoint.sh /etc/"   44 minutes ago      Up 44 minutes                  0.0.0.0:5000->5000/tcp   registry

15340ee09614        busybox             "/bin/sh"                4 hours ago         Exited (1) About an hour ago                            sleepy_mccarthy

二、无法创建pod故障现象

1、查看pod状态

[root@k8s-master ~]# kubectl get pod

NAME      READY     STATUS              RESTARTS   AGE

nginx     0/1       ContainerCreating   0          2m

2、获取pod详细信息(拍错常用命令)

[root@k8s-master ~]# kubectl describe pod nginx

Name:		nginx

Namespace:	default

Node:		k8s-node1/10.0.128.1

Start Time:	Sun, 20 Jan 2019 13:04:51 +0800

Labels:		app=web

Status:		Pending

IP:

Controllers:	<none>

Containers:

  nginx:

    Container ID:

    Image:			10.0.128.0:5000/nginx:latest

    Image ID:

    Port:			80/TCP

    State:			Waiting

      Reason:			ContainerCreating

    Ready:			False

    Restart Count:		0

    Volume Mounts:		<none>

    Environment Variables:	<none>

Conditions:

  Type		Status

  Initialized 	True

  Ready 	False

  PodScheduled 	True

No volumes.

QoS Class:	BestEffort

Tolerations:	<none>

Events:

  FirstSeen	LastSeen	Count	From			SubObjectPath	Type		Reason		Message

  ---------	--------	-----	----			-------------	--------	------		-------

  3m		3m		1	{default-scheduler }			Normal		Scheduled	Successfully assigned nginx to k8s-node1

  3m		46s		5	{kubelet k8s-node1}			Warning		FailedSync	Error syncing pod, skipping: failed to "StartContainer" for "POD" with ErrImagePull:

  "image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request.

  details: (open /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt: no such file or directory)"

  3m	8s	12	{kubelet k8s-node1}		Warning	FailedSync	Error syncing pod, skipping: failed to "StartContainer" for "POD" with ImagePullBackOff: "Back-off pulling image \"registry.access.redhat.com/rhel7/pod-infrastructure:latest\""

错误是无法从registry.access.redhat.com仓库获取镜像，解决办法是更换镜像地址

三、pod故障解决方案

1、搜索pod-infrastructure

[root@k8s-master ~]# docker search pod-infrastructure

kubernetes云平台管理实战： 最小的资源pod（二）

2、下载并上传到私有仓库

[root@k8s-master ~]# docker pull tianyebj/pod-infrastructure

Using default tag: latest

Trying to pull repository docker.io/tianyebj/pod-infrastructure ...

latest: Pulling from docker.io/tianyebj/pod-infrastructure

7bd78273b666: Pull complete

c196631bd9ac: Pull complete

3c917e6a9e1a: Pull complete

Digest: sha256:73cc48728e707b74f99d17b4e802d836e22d373aee901fdcaa781b056cdabf5c

[root@k8s-master ~]# docker images

REPOSITORY                              TAG                 IMAGE ID            CREATED             SIZE

docker.io/registry                      latest              33fbbf4a24e5        2 weeks ago         24.17 MB

10.0.128.0:5000/busybox                 latest              3a093384ac30        2 weeks ago         1.199 MB

docker.io/busybox                       latest              3a093384ac30        2 weeks ago         1.199 MB

10.0.128.0:5000/nginx                   latest              7042885a156a        3 weeks ago         109.2 MB

docker.io/nginx                         latest              7042885a156a        3 weeks ago         109.2 MB

docker.io/tianyebj/pod-infrastructure   latest              34d3450d733b        24 months ago       205 MB

[root@k8s-master ~]# docker tag docker.io/tianyebj/pod-infrastructure:latest 10.0.128.0:5000/pod-infrastructure:latest

[root@k8s-master ~]# docker push 10.0.128.0:5000/pod-infrastructure:latest

The push refers to a repository [10.0.128.0:5000/pod-infrastructure]

ba3d4cbbb261: Pushed

0a081b45cb84: Pushed

df9d2808b9a9: Pushed

latest: digest: sha256:a378b2d7a92231ffb07fdd9dbd2a52c3c439f19c8d675a0d8d9ab74950b15a1b size: 948

3、修改镜像的地址

vim /etc/kubernetes/kubelet

修改内容如下：

KUBELET_POD_INFRA_CONTAINER="--pod-infra-container-image=10.0.128.0:5000/pod-infrastructure:latest"

4、再次查看pod详细信息

[root@k8s-master ~]# kubectl describe pod nginx

Name:		nginx

Namespace:	default

Node:		k8s-node1/10.0.128.1

Start Time:	Sun, 20 Jan 2019 13:04:51 +0800

Labels:		app=web

Status:		Running

IP:		172.16.10.2

Controllers:	<none>

Containers:

  nginx:

    Container ID:		docker://27d25a2ee0248b103991a27b81e3f244382ebdb642694e2aeb5503c373fdb912

    Image:			10.0.128.0:5000/nginx:latest

    Image ID:			docker-pullable://10.0.128.0:5000/nginx@sha256:e2847e35d4e0e2d459a7696538cbfea42ea2d3b8a1ee8329ba7e68694950afd3

    Port:			80/TCP

    State:			Running

      Started:			Sun, 20 Jan 2019 13:48:30 +0800

    Ready:			True

    Restart Count:		0

    Volume Mounts:		<none>

    Environment Variables:	<none>

Conditions:

  Type		Status

  Initialized 	True

  Ready 	True

  PodScheduled 	True

No volumes.

QoS Class:	BestEffort

Tolerations:	<none>

Events:

  FirstSeen	LastSeen	Count	From			SubObjectPath	Type		Reason		Message

  ---------	--------	-----	----			-------------	--------	------		-------

  48m		48m		1	{default-scheduler }			Normal		Scheduled	Successfully assigned nginx to k8s-node1

  48m		6m		13	{kubelet k8s-node1}			Warning		FailedSync	Error syncing pod, skipping: failed to "StartContainer" for "POD" with ErrImagePull: "image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request.  details: (open /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt: no such file or directory)"

  47m	5m	182	{kubelet k8s-node1}		Warning	FailedSync	Error syncing pod, skipping: failed to "StartContainer" for "POD" with ImagePullBackOff: "Back-off pulling image \"registry.access.redhat.com/rhel7/pod-infrastructure:latest\""

  4m	4m	1	{kubelet k8s-node1}	spec.containers{nginx}	Normal	Pulling			pulling image "10.0.128.0:5000/nginx:latest"

  4m	4m	2	{kubelet k8s-node1}				Warning	MissingClusterDNS	kubelet does not have ClusterDNS IP configured and cannot create Pod using "ClusterFirst" policy. Falling back to DNSDefault policy.

  4m	4m	1	{kubelet k8s-node1}	spec.containers{nginx}	Normal	Pulled			Successfully pulled image "10.0.128.0:5000/nginx:latest"

  4m	4m	1	{kubelet k8s-node1}	spec.containers{nginx}	Normal	Created			Created container with docker id 27d25a2ee024; Security:[seccomp=unconfined]

  4m	4m	1	

[root@k8s-master ~]# kubectl get pod -o wide

NAME      READY     STATUS    RESTARTS   AGE       IP            NODE

nginx     1/1       Running   0          48m       172.16.10.2   k8s-node1

[root@k8s-master ~]# curl 172.16.10.2

<!DOCTYPE html>

<html>

<head>

<title>Welcome to nginx!</title>

<style>

    body {

        width: 35em;

        margin: 0 auto;

        font-family: Tahoma, Verdana, Arial, sans-serif;

    }

</style>

</head>

<body>

<h1>Welcome to nginx!</h1>

<p>If you see this page, the nginx web server is successfully installed and

working. Further configuration is required.</p>

<p>For online documentation and support please refer to

<a href="http://nginx.org/">nginx.org</a>.<br/>

Commercial support is available at

<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>

</body>

</html>

elet k8s-node1}	spec.containers{nginx}	Normal	Started			Started container with docker id 27d25a2ee024

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