深入kubernetes之Pod——一pod多容器
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六、深入Pod——一pod多容器
一pod多容器，可以说是kube精华所在，让多个同应用的单一容器可以整合到一个类虚拟机中，使其所有容器共用一个vm的资源，提高耦合度，神来之笔，从而方便副本的复制，提高整体的可用性
接下来会从我自己的学习历程，讲诉一pod多容器，其中历经的困难，此问题有困扰一个月之久。
1、测试过程：
根据文章：http://www.csdn.net/article/2014-12-18/2823196 ，看到pod还有一pod多容器的功能，仅是看了文章便激动不已，一pod多容器，可以说是kube的精华所在，具体优点，可以参考第一章的简介（14项）
①、第一次测试——失败：
使用文件：【nginx_redis_pod.json】
目的：一pod两容器
结论：失败，1个启动成功，1个启动失败，一直在重启，不知道是配置文件的问题，还是什么
提前说明下各image启动的端口：
images | port |
www.perofu.com:7070/centos6.4_ip_nginx | 80、22 |
www.perofu.com:7070/centos6.4_redis | 6379、22 |
[[email protected] pod_nginx_redis_kube]# vi nginx_redis_pod.json { "id": "nginx-1", "kind": "Pod", "metadata": { "name": "nginx-1" }, "apiVersion": "v1", "desiredState": { "manifest": { "version": "v1", "id": "nginx-1" } }, "spec": { "containers": [ { "name": "nginx-1", "image": "www.perofu.com:7070/centos6.4_ip_nginx", "command": [ "/etc/rc.local" ] }, { "name": "redis", "image": "www.perofu.com:7070/centos6.4_redis", "command": [ "/etc/rc.local" ] } ] }, "labels": { "name": "nginx-1" } } ~ "nginx_redis_pod.json" 36L, 602C written [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl create -f nginx_redis_pod.json pods/nginx-1 [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl get pod NAME READY STATUS RESTARTS AGE nginx-1 0/2 Pending 0 4s [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl get pod NAME READY STATUS RESTARTS AGE nginx-1 2/2 Running 1 56s [[email protected] pod_nginx_redis_kube]# [[email protected] pod_nginx_redis_kube]# [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl get pod NAME READY STATUS RESTARTS AGE nginx-1 1/2 Running 2 59s |
②、第二次测试——失败：
使用文件：【nginx_redis_pod_test.json】
目的：看到node，都是192.168.16.240，就想，一个pod里的容器，是不是都不能放到一个node中？
结论：失败，1个启动成功，1个启动失败，一直在重启，
加了一个node，一个pod就只能在一个node上，有的容器能起来，有的不行，没有什么规律，看官网的多容器yaml写的，怎么就不行？
提前说明下各image启动的端口：
images | port |
www.perofu.com:7070/centos6.4_ip_nginx | 80、22 |
www.perofu.com:7070/centos6.4_redis | 6379、22 |
[[email protected] pod_nginx_redis_kube]# cat nginx_redis_pod_test.json --- apiVersion: v1 kind: Pod metadata: name: www spec: containers: - name: nginx image: www.perofu.com:7070/centos6.4_ip_nginx command: - /etc/rc.local - name: redis-1 image: www.perofu.com:7070/centos6.4_redis command: - /etc/rc.local [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl describe pod www Name: www Namespace: default Image(s): www.perofu.com:7070/centos6.4_ip_nginx,www.perofu.com:7070/centos6.4_redis Node: 192.168.16.240/192.168.16.240 Labels: <none> Status: Running Reason: Message: IP: 172.22.2.2 Replication Controllers: <none> Containers: nginx: Image: www.perofu.com:7070/centos6.4_ip_nginx State: Running Started: Thu, 21 Jan 2016 16:07:42 +0800 Ready: False Restart Count: 9 redis-1: Image: www.perofu.com:7070/centos6.4_redis State: Running Started: Thu, 21 Jan 2016 16:04:19 +0800 Ready: True Restart Count: 0 Conditions: Type Status Ready False Events: FirstSeen LastSeen Count From SubobjectPath Reason Message Thu, 21 Jan 2016 16:03:34 +0800 Thu, 21 Jan 2016 16:03:34 +0800 1 {scheduler } scheduled Successfully assigned www to 192.168.16.240 Thu, 21 Jan 2016 16:04:16 +0800 Thu, 21 Jan 2016 16:04:16 +0800 1 {kubelet 192.168.16.240} implicitly required container POD pulled Pod container image "gcr.io/google_containers/pause:0.8.0" already present on machine Thu, 21 Jan 2016 16:04:17 +0800 Thu, 21 Jan 2016 16:04:17 +0800 1 {kubelet 192.168.16.240} implicitly required container POD created Created with docker id c7884e18b3ff Thu, 21 Jan 2016 16:04:17 +0800 Thu, 21 Jan 2016 16:04:17 +0800 1 {kubelet 192.168.16.240} implicitly required container POD started Started with docker id c7884e18b3ff Thu, 21 Jan 2016 16:04:18 +0800 Thu, 21 Jan 2016 16:04:18 +0800 1 {kubelet 192.168.16.240} spec.containers{nginx} created Created with docker id ce71cdeddab3 Thu, 21 Jan 2016 16:04:18 +0800 Thu, 21 Jan 2016 16:04:18 +0800 1 {kubelet 192.168.16.240} spec.containers{nginx} started Started with docker id ce71cdeddab3 Thu, 21 Jan 2016 16:04:19 +0800 Thu, 21 Jan 2016 16:04:19 +0800 1 {kubelet 192.168.16.240} spec.containers{redis-1} created Created with docker id 15ca805a9e99 Thu, 21 Jan 2016 16:04:19 +0800 Thu, 21 Jan 2016 16:04:19 +0800 1 {kubelet 192.168.16.240} spec.containers{redis-1} started Started with docker id 15ca805a9e99 Thu, 21 Jan 2016 16:04:32 +0800 Thu, 21 Jan 2016 16:04:32 +0800 1 {kubelet 192.168.16.240} spec.containers{nginx} created Created with docker id edfacd145c9b Thu, 21 Jan 2016 16:04:32 +0800 Thu, 21 Jan 2016 16:04:32 +0800 1 {kubelet 192.168.16.240} spec.containers{nginx} started Started with docker id edfacd145c9b
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③、第三次测试——侥幸成功：
使用文件：【test2_redis_nginx_pod.yaml 】
目的：尝试使用其他image（不带command启动的）进行测试
结论：成功，怀疑是配制文件只能允许一个command的
说明一下，这一次和之前yaml的差别，
成功：两个images，一个有command，一个没有
失败：两个images，两个都有command
再加上网上的文档，包括官网的，都是没有command的，由于我是自己做的images，都是通过command进行启动的，就一直失败。
不是配置文件的问题，而是一个kube的坑，由此可得：
【在一个pod中创建多个容器，只能有一个images可以使用command，否则就会有容器一直在重启】
新发现：看到node，都是192.168.16.240，就想，一个pod里的容器，是不是都不能放到一个node中？
新发现之测试结果：加了一个node，一个pod就只能在一个node上，有的容器能起来，有的不行，没有什么规律，看官网的多容器yaml写的，怎么就不行？
提前说明下各image启动的端口：
images | port |
www.perofu.com:7070/registry | 5000 |
www.perofu.com:7070/centos6.4_redis | 6379、22 |
[[email protected] pod_nginx_redis_kube]# vi test2_redis_nginx_pod.yaml
name: perofu4 labels: name: perofu4 spec: replicas: 1 selector: name: perofu4 template: metadata: labels: name: perofu4 spec: containers: - name: redis image: www.perofu.com:7070/centos6.4_redis command: - ‘/bin/bash‘ - ‘-c‘ - ‘/etc/rc.local‘ - name: nginx image: www.perofu.com:7070/registry [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl create -f test2_redis_nginx_pod.yaml replicationcontrollers/perofu4 [[email protected] pod_nginx_redis_kube]# [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl get pod NAME READY STATUS RESTARTS AGE perofu-wduar 1/2 Running 1 14s [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl get pod NAME READY STATUS RESTARTS AGE perofu-wduar 2/2 Running 2 2m [[email protected] pod_nginx_redis_kube]# [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl get pod NAME READY STATUS RESTARTS AGE perofu-wduar 2/2 Running 2 2m [[email protected] pod_nginx_redis_kube]# [[email protected] pod_nginx_redis_kube]# /usr/bin/kubectl describe pod perofu-wduar Name: perofu-wduar Namespace: default Image(s): www.perofu.com:7070/centos6.4_redis,www.perofu.com:7070/registry Node: 192.168.16.240/192.168.16.240 Labels: name=perofu4 Status: Running Reason: Message: IP: 172.22.2.9 Replication Controllers: perofu4 (1/1 replicas created) Containers: redis: Image: www.perofu.com:7070/centos6.4_redis State: Running Started: Tue, 16 Feb 2016 16:54:32 +0800 Ready: True Restart Count: 0 nginx: Image: www.perofu.com:7070/registry State: Running Started: Tue, 16 Feb 2016 16:54:50 +0800 Ready: True Restart Count: 2 Conditions: Type Status Ready True
#验证 [[email protected] ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 5c6581d919a5 www.perofu.com:7070/registry:latest "docker-registry" 2 minutes ago Up 2 minutes k8s_nginx.65e9d290_perofu-wduar_default_eaa53352-cc1f-11e5-938c-000c29eae008_03b774d2 08315bce234b centos6.4_redis:latest "/bin/bash -c /etc/r 2 minutes ago Up 2 minutes k8s_redis.510ddc4c_perofu-wduar_default_eaa53352-cc1f-11e5-938c-000c29eae008_3e6b7907 15bd3a44a717 gcr.io/google_containers/pause:0.8.0 "/pause" 2 minutes ago Up 2 minutes k8s_POD.e4cc795_perofu-wduar_default_eaa53352-cc1f-11e5-938c-000c29eae008_8c768cca [[email protected] ~]# [[email protected] ~]# [[email protected] ~]# docker exec -it 08315bce234b /bin/bash [[email protected] /]# [[email protected] /]# ifconfig eth0 Link encap:Ethernet HWaddr 02:42:AC:16:02:09 inet addr:172.22.2.9 Bcast:0.0.0.0 Mask:255.255.255.0 inet6 addr: fe80::42:acff:fe16:209/64 Scope:Link UP BROADCAST RUNNING MTU:1500 Metric:1 RX packets:10 errors:0 dropped:0 overruns:0 frame:0 TX packets:10 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:823 (823.0 b) TX bytes:718 (718.0 b)
lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:8 errors:0 dropped:0 overruns:0 frame:0 TX packets:8 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:518 (518.0 b) TX bytes:518 (518.0 b)
[[email protected] /]# netstat -anplt Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 26/sshd tcp &n 以上是关于深入kubernetes之Pod——一pod多容器的主要内容，如果未能解决你的问题，请参考以下文章 |