在前面的文章中介绍了Pod的使用方法，示例中的Pod包含一个容器，这篇文章介绍一下包含多个容器的Pod的使用方法。
YAML文件示例
[root@host131 Pod]# cat
---
apiVersion: v1
kind: Pod
metadata:
name: multi-pods
spec:
containers:
- name: blue-pod-container
image: busybox:1.31.1
command: ["sleep"]
args: ["1000"]
- name: green-pod-container
image: busybox:1.30.1
command: ["sleep"]
args: ["10000"]
- name: yellow-pod-container
image: busybox:1.30.1
command: ["sleep"]
args: ["100000"]
...
[root@host131 Pod]#
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生成Pod
[root@host131 Pod]# kubectl create -f
pod/multi-pods created
[root@host131 Pod]#
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确认Pod信息
使用kubectl get pods命令可以获取此pod的详细信息，可以看到READY显示为3/3，说明包含三个容器全部正常启动，整体状态STATUS为Running状态，Pod本身的IP为10.254.176.3，Pod名称为multi-pods。
[root@host131 Pod]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
multi-pods 3/3 Running 0 27s 10.254.176.3 192.168.163.131 <none> <none>
[root@host131 Pod]#
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然后可以使用kubectl describe查看pod的详细信息：
[root@host131 Pod]# kubectl describe pod/multi-pods
Name: multi-pods
Namespace: default
Priority: 0
Node: 192.168.163.131/192.168.163.131
Start Time: Sun, 09 Feb 2020 04:34:18 -0500
Labels: <none>
Annotations: <none>
Status: Running
IP: 10.254.176.3
IPs:
IP: 10.254.176.3
Containers:
blue-pod-container:
Container ID: docker://881da8a39e6a9999cce25ef227c97e8680379d97cd190e6a98ff25f49a3f7469
Image: busybox:1.31.1
Image ID: docker-pullable://busybox@sha256:6915be4043561d64e0ab0f8f098dc2ac48e077fe23f488ac24b665166898115a
Port: <none>
Host Port: <none>
Command:
sleep
Args:
1000
State: Running
Started: Sun, 09 Feb 2020 04:34:19 -0500
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets//serviceaccount from default-token-kzxwt (ro)
green-pod-container:
Container ID: docker://b60d1cf06ff68ffae44e13f33d84b12b8525707af6de1836abdc5905a135166f
Image: busybox:1.30.1
Image ID: docker-pullable://busybox@sha256:4b6ad3a68d34da29bf7c8ccb5d355ba8b4babcad1f99798204e7abb43e54ee3d
Port: <none>
Host Port: <none>
Command:
sleep
Args:
10000
State: Running
Started: Sun, 09 Feb 2020 04:34:19 -0500
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets//serviceaccount from default-token-kzxwt (ro)
yellow-pod-container:
Container ID: docker://8e500fef966ab861843d46076bdb07fa5443041bcc6b20c2a415ef5aed181cdf
Image: busybox:1.30.1
Image ID: docker-pullable://busybox@sha256:4b6ad3a68d34da29bf7c8ccb5d355ba8b4babcad1f99798204e7abb43e54ee3d
Port: <none>
Host Port: <none>
Command:
sleep
Args:
100000
State: Running
Started: Sun, 09 Feb 2020 04:34:19 -0500
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets//serviceaccount from default-token-kzxwt (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-kzxwt:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-kzxwt
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: /not-ready:NoExecute for 300s
/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m47s default-scheduler Successfully assigned default/multi-pods to 192.168.163.131
Normal Pulled 2m46s kubelet, 192.168.163.131 Container image "busybox:1.31.1" already present on machine
Normal Created 2m46s kubelet, 192.168.163.131 Created container blue-pod-container
Normal Started 2m46s kubelet, 192.168.163.131 Started container blue-pod-container
Normal Pulled 2m46s kubelet, 192.168.163.131 Container image "busybox:1.30.1" already present on machine
Normal Created 2m46s kubelet, 192.168.163.131 Created container green-pod-container
Normal Started 2m46s kubelet, 192.168.163.131 Started container green-pod-container
Normal Pulled 2m46s kubelet, 192.168.163.131 Container image "busybox:1.30.1" already present on machine
Normal Created 2m46s kubelet, 192.168.163.131 Created container yellow-pod-container
Normal Started 2m46s kubelet, 192.168.163.131 Started container yellow-pod-container
[root@host131 Pod]#
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可以看到在Containers段显示了三个容器的详细信息，而在Event中也可以看到三个容器的创建过程。
进入容器
Pod中只有一个容器时，使用如下命令即可进入到容器之中：
执行命令：kubectl exec -it pod名称 sh或者bash
而如果有多个容器时，则需要使用-c指定容器名称：
执行命令：kubectl exec -it pod名称 -c 容器名称 sh或者bash
比如进入multi-pods中名为yellow-pod-container ：
[root@host131 Pod]# kubectl exec -it multi-pods -c yellow-pod-container sh
/ # ps -ef
PID USER TIME COMMAND
1 root 0:00 sleep 100000
6 root 0:00 sh
11 root 0:00 ps -ef
/ # busybox |grep BusyBox
BusyBox v1.30.1 (2019-05-09 01:23:43 UTC) multi-call binary.
BusyBox is copyrighted by many authors between 1998-2015.
BusyBox is a multi-call binary that combines many common Unix
link to busybox for each function they wish to use and BusyBox
/ # hostname
multi-pods
/ #
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pause镜像确认，使用docker ps命令可以确认到包含pause在内的4个容器，pause容器作为此Pod的根容器，负责整个Pod的网络信息
[root@host131 Pod]# docker ps |grep multi-pods
8e500fef966a 64f5d945efcc "sleep 100000" 8 minutes ago Up 8 minutes k8s_yellow-pod-container_multi-pods_default_3c744cee-6ce3-4de3-99ab-f8909fee0147_0
b60d1cf06ff6 64f5d945efcc "sleep 10000" 8 minutes ago Up 8 minutes k8s_green-pod-container_multi-pods_default_3c744cee-6ce3-4de3-99ab-f8909fee0147_0
881da8a39e6a 6d5fcfe5ff17 "sleep 1000" 8 minutes ago Up 8 minutes k8s_blue-pod-container_multi-pods_default_3c744cee-6ce3-4de3-99ab-f8909fee0147_0
44d9b05a6d1b /google_containers/pause-amd64:3.1 "/pause" 8 minutes ago Up 8 minutes k8s_POD_multi-pods_default_3c744cee-6ce3-4de3-99ab-f8909fee0147_0
[root@host131 Pod]#
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首先确认pause的id
[root@host131 Pod]# docker inspect k8s_POD_multi-pods_default_3c744cee-6ce3-4de3-99ab-f8909fee0147_0 |grep Id
"Id": "44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb",
[root@host131 Pod]#
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然后可以确认到在其余的容器中都和此Pod有所关联,可以看到Pause作为根容器为其余容器所起到的作用。
[root@host131 Pod]# docker inspect k8s_yellow-pod-container_multi-pods_default_3c744cee-6ce3-4de3-99ab-f8909fee0147_0 |grep 44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb
"ResolvConfPath": "/var/lib/docker/containers/44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb/",
"HostnamePath": "/var/lib/docker/containers/44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb/hostname",
"NetworkMode": "container:44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb",
"IpcMode": "container:44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb",
"": "44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb"
[root@host131 Pod]#
[root@host131 Pod]# docker inspect k8s_green-pod-container_multi-pods_default_3c744cee-6ce3-4de3-99ab-f8909fee0147_0 |grep 44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb
"ResolvConfPath": "/var/lib/docker/containers/44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb/",
"HostnamePath": "/var/lib/docker/containers/44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb/hostname",
"NetworkMode": "container:44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb",
"IpcMode": "container:44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb",
"": "44d9b05a6d1b9f33e170a70a4db304b92e4dbbdd3d0a38efaca0513ad8b86acb"
[root@host131 Pod]#
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另外如果不使用-c指定容器时，缺省会进入第一个容器中
[root@host131 Pod]# kubectl exec -it multi-pods sh
Defaulting container name to blue-pod-container.
Use 'kubectl describe pod/multi-pods -n default' to see all of the containers in this pod.
/ #
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