Docker 是一个开源项目，诞生于 2013 年初，最初是 dotCloud 公司内部的一个业余项目。它基于 Google 公司推出的 Go 语言实现。 项目后来加入了 Linux 基金会，遵从了 Apache 2.0 协议，项目代码在 GitHub 上进行维护。
Docker 自开源后受到广泛的关注和讨论，以至于 dotCloud 公司后来都改名为 Docker Inc。Redhat 已经在其 RHEL6.5 中集中支持 Docker；Google 也在其 PaaS 产品中广泛应用。
Docker 项目的目标是实现轻量级的操作系统虚拟化解决方案。 Docker 的基础是 Linux 容器（LXC）等技术。
在 LXC 的基础上 Docker 进行了进一步的封装，让用户不需要去关心容器的管理，使得操作更为简便。用户操作 Docker 的容器就
像操作一个快速轻量级的虚拟机一样简单。
1.下载安装
在centos上运行docker必须是64位并且内核在2.6.32-431或者更高内核版本，建议完全更新系统
[root@iZ25gswv4olZ ~]# getconf LONG_BIT ---查看位数32/64 64 [root@iZ25gswv4olZ ~]# uname -r --查看内核版本 2.6.32-431.23.3.el6.x86_64 [root@iZ25gswv4olZ ~]# yum update ---完全更新系统 [root@iZ25gswv4olZ ~]# uname -r 2.6.32-431.23.3.el6.x86_64 [root@iZ25gswv4olZ ~]# lsb_release -a ----列出所有版本信息 LSB Version: :base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch Distributor ID: CentOS Description: CentOS release 6.5 (Final) Release: 6.5 Codename: Final
----下载Docker。
[root@iZ25gswv4olZ /]# sudo yum install http://mirrors.yun-idc.com/epel/6/i386/epel-release-6-8.noarch.rpm [root@iZ25gswv4olZ /]# sudo yum install docker-io
2.启动
现在，它已经安装好了，让我们来启动docker进程
[root@iZ25gswv4olZ ~]# service docker start
它将会输出如下的信息：
Starting cgconfig service: [ OK ] Starting docker: [ OK ]
如果我们需要开机自启动，如下：
[root@iZ25gswv4olZ ~]#chkconfig docker on
3.最新的centos镜像
现在我们确认docker是否正常工作，首先我们需要获取最新的centos镜像
[root@iZ25gswv4olZ /]# sudo docker pull centos:latest
它将会输出如下的信息：
Cannot connect to the Docker daemon. Is 'docker -d' running on this host? [root@iZ25gswv4olZ local]# docker -d
它将会输出如下的信息：
WARN[0000] You are running linux kernel version 2.6.32-431.23.3.el6.x86_64, which might be unstable running docker.
Please upgrade your kernel to 3.10.0. INFO[0000] [graphdriver] using prior storage driver "devicemapper" INFO[0000] Listening for HTTP on unix (/var/run/docker.sock) WARN[0000] Running modprobe bridge nf_nat failed with message: , error: exit status 1 FATA[0000] Error starting daemon: Error initializing network controller: Error creating default "bridge" network: operation not supported
因为阿里云默认把所有的私网地址段都加到导致docker找不到一个可用的IP段了。
[root@iZ25gswv4olZ /]# ifconfig
它将会输出如下的信息：
eth0 Link encap:Ethernet HWaddr 00:16:3E:00:18:94 inet addr:10.172.193.40 Bcast:10.172.199.255 Mask:255.255.248.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2694 errors:0 dropped:0 overruns:0 frame:0 TX packets:235 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:122753 (119.8 KiB) TX bytes:20141 (19.6 KiB) Interrupt:148 eth1 Link encap:Ethernet HWaddr 00:16:3E:00:43:32 inet addr:182.92.177.208 Bcast:182.92.179.255 Mask:255.255.252.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:473435 errors:0 dropped:0 overruns:0 frame:0 TX packets:395 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:19904390 (18.9 MiB) TX bytes:46006 (44.9 KiB) Interrupt:147 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
[root@iZ25gswv4olZ /]# docker -bip=10.172.193.40/24 -d &
它将会输出如下的信息：
[1] 1393 [root@iZ25gswv4olZ /]# Warning: '-bip' is deprecated, it will be replaced by '--bip' soon. See usage. INFO[0000] +job serveapi(unix:///var/run/docker.sock) INFO[0000] WARNING: You are running linux kernel version 2.6.32-504.23.4.el6.x86_64, which might be unstable running docker. Please upgrade your kernel to 3.8.0. INFO[0000] +job init_networkdriver() INFO[0000] Listening for HTTP on unix (/var/run/docker.sock) INFO[0000] -job init_networkdriver() = OK (0) INFO[0000] Loading containers: start. INFO[0000] Loading containers: done. INFO[0000] docker daemon: 1.5.0 a8a31ef/1.5.0; execdriver: native-0.2; graphdriver: devicemapper INFO[0000] +job acceptconnections() INFO[0000] -job acceptconnections() = OK (0)
[root@iZ25gswv4olZ /]# lxc-checkconfig
它将会输出如下的信息：
Kernel configuration not found at /proc/config.gz; searching... Kernel configuration found at /boot/config-2.6.32-504.23.4.el6.x86_64 --- Namespaces --- Namespaces: enabled Utsname namespace: enabled Ipc namespace: enabled Pid namespace: enabled User namespace: enabled Network namespace: enabled Multiple /dev/pts instances: enabled --- Control groups --- Cgroup: enabled Cgroup namespace: enabled Cgroup device: enabled Cgroup sched: enabled Cgroup cpu account: enabled Cgroup memory controller: /usr/bin/lxc-checkconfig: line 103: [: too many arguments enabled Cgroup cpuset: enabled --- Misc --- Veth pair device: enabled Macvlan: enabled Vlan: enabled File capabilities: /usr/bin/lxc-checkconfig: line 118: [: -gt: unary operator expected Note : Before booting a new kernel, you can check its configuration usage : CONFIG=/path/to/config /usr/bin/lxc-checkconfig
可以看到 Control groups 项目都是支持的，所以我们暂时忽略这个告警。
测试使用-我们需要下载最新的centos镜像
注意：由于 Aliyun 的网络直接 pull 官方镜像也不是很稳定，可选择官方标准镜像来测试
[root@iZ25gswv4olZ ~]# sudo docker pull centos:latest
它将会输出如下的信息：
INFO[0623] POST /v1.17/images/create?fromImage=centos%3Alatest INFO[0623] +job pull(centos, latest) INFO[0623] +job resolve_repository(centos) INFO[0623] -job resolve_repository(centos) = OK (0) INFO[0623] +job trust_update_base() INFO[0624] -job trust_update_base() = OK (0) Pulling repository centos 7322fbe74aa5: Download complete f1b10cd84249: Download complete c852f6d61e65: Download complete INFO[0855] +job log(pull, centos:latest, ) INFO[0855] -job log(pull, centos:latest, ) = OK (0) INFO[0855] -job pull(centos, latest) = OK (0) Status: Downloaded newer image for centos:latest
下一步，我们要确保通过如下命令可以看到镜像运行情况：
[root@iZ25gswv4olZ /]# docker images centos
它将会输出如下的信息：
INFO[3912] GET /v1.17/images/json?filter=centos INFO[3912] +job images() INFO[3912] -job images() = OK (0) REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZEcentos 7 7322fbe74aa5 4 weeks ago 172.2 MB centos latest 7322fbe74aa5 4 weeks ago 172.2 MB centos centos7 7322fbe74aa5 4 weeks ago 172.2 MB
运行简单的bash shell来测试这个镜像
[root@iZ25gswv4olZ /]# docker run -i -t centos /bin/bash
它将会输出如下的信息：
INFO[0481] POST /v1.17/containers/create INFO[0481] +job create() INFO[0481] +job log(create, 523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a2266507e45c INFO[0481] -job log(create, 523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a2266507e45c INFO[0481] -job create() = OK (0) INFO[0481] POST /v1.17/containers/523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a22665 INFO[0481] +job container_inspect(523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a22665 INFO[0481] -job container_inspect(523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a22665 INFO[0481] +job attach(523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a2266507e45c1873) 07e45c1873) INFO[0481] +job allocate_interface(523e56a0b3bd09f625793a97a5a9e2a22be804326 3a97a5a9e2a22be804326d919bf4a2266507e45c1873, centos:7) INFO[0481] -job log(start, 523e5 0482] POST /v1.17/containers/523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a2266507e45 4326d919bf4a2266507e45c1873, 54, 270) = OK (0) [root@523e56a0b3bd /]# INFO[0487] POST /v1.17/containers/523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a2266507e45c1873/resize?h=23&w=88 INFO[0487] +job resize(523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a2266507e45c1873, 23, 88) INFO[0487] -job resize(523e56a0b3bd09f625793a97a5a9e2a22be804326d919bf4a2266507e45c1873, 23, 88) = OK (0)
如果正常，你会获得一个简单的bash提示，输入exit退出。
# exit