1 安装docker的apt源
apt-get install apt-transport-https ca-certificates curl software-properties-common
2
添加docker官方的GPG
root@zhf-linux:/home#
curl -s https://download.docker.com/linux/ubuntu/gpg | sudo apt-key
add -
OK
3
添加docker的源。如果没有docker.list则自己创建一个
root@zhf-linux:/etc/apt/sources.list.d#
bash -c "echo deb https://get.docker.io/ubuntu docker main >
/etc/apt/sources.list.d/docker.list"
4
安装docker
apt
install docker.io
5
查看docker的版本:
root@zhf-linux:/var/lib/docker#
docker version
Client:
Version:
1.13.1
API
version: 1.26
Go
version: go1.6.2
Git
commit: 092cba3
Built:
Thu Sep 7 17:23:05 2017
OS/Arch:
linux/386
Server:
Version:
1.13.1
API
version: 1.26 (minimum version 1.12)
Go
version: go1.6.2
Git
commit: 092cba3
Built:
Thu Sep 7 17:23:05 2017
OS/Arch:
linux/386
Experimental:
false
到这里docker整个就安装完了,我们来看下如何来启动一个镜像
1
通过docker
run命令来启动一个httpd的镜像。如果没有发现httpd镜像会从docker
hub下载镜像。下载完成后,镜像httpd被保存到本地
docker
run -d -p 80:80 httpd
2
docker images可以看到已经下载到本地
root@zhf-linux:/home/zhf/zhf/c_prj/make_function#
docker images
REPOSITORY
TAG IMAGE ID CREATED
SIZE
httpd
latest 7659d5a9a057 2 weeks ago
189 MB
3
docker ps显示容器正在运行
root@zhf-linux:/home/zhf/zhf/c_prj/make_function#
docker ps
CONTAINER
ID IMAGE COMMAND CREATED
STATUS PORTS NAMES
39ae70ca12b2
httpd "httpd-foreground" 6 minutes
ago Up 6 minutes 0.0.0.0:80->80/tcp
compassionate_bohr
接下来看下如何下载一个镜像。通过docker
pull下载。docker
pull会从Docker
Hub进行下载。
root@zhf-linux:/home/zhf/zhf/c_prj/make_function#
docker pull hello-world
Using
default tag: latest
latest:
Pulling from library/hello-world
cf7dde121f94:
Pull complete
Digest:
sha256:0e06ef5e1945a718b02a8c319e15bae44f47039005530bc617a5d071190ed3fc
Status:
Downloaded newer image for hello-world:latest
通过docker
images看到这个镜像只有600多K
root@zhf-linux:/home/zhf/zhf/c_prj/make_function#
docker images hello-world
REPOSITORY
TAG IMAGE ID CREATED
SIZE
hello-world
latest abd130ec0722 3 months ago
665 kB
通过docker
run hello-world来执行。结果如下:
root@zhf-linux:/home/zhf/zhf/c_prj/make_function#
docker run hello-world
Hello
from Docker!
This
message shows that your installation appears to be working correctly.
To
generate this message, Docker took the following steps:
1.
The Docker client contacted the Docker daemon.
2.
The Docker daemon pulled the "hello-world" image from the
Docker Hub.
3.
The Docker daemon created a new container from that image which runs
the
executable
that produces the output you are currently reading.
4.
The Docker daemon streamed that output to the Docker client, which
sent it
to
your terminal.
To
try something more ambitious, you can run an Ubuntu container with:
$
docker run -it ubuntu bash
Share
images, automate workflows, and more with a free Docker ID:
https://cloud.docker.com/
For
more examples and ideas, visit:
https://docs.docker.com/engine/userguide/
下载的docker镜像默认存储路径是/var/lib/docker
.具体的镜像文件就在containers文件夹中
root@zhf-linux:/var/lib/docker#
ls -al
total
44
drwx--x--x
11 root root 4096 Oct 30 22:28 .
drwxr-xr-x
79 root root 4096 Dec 11 21:08 ..
drwx------
5 root root 4096 Oct 30 22:28 aufs
drwx------
8 root root 4096 Dec 19 20:59 containers
drwx------
3 root root 4096 Oct 30 22:28 image
drwxr-x---
3 root root 4096 Oct 30 22:28 network
drwx------
4 root root 4096 Oct 30 22:28 plugins
drwx------
2 root root 4096 Oct 30 22:28 swarm
drwx------
2 root root 4096 Dec 19 20:50 tmp
drwx------
2 root root 4096 Oct 30 22:28 trust
drwx------
2 root root 4096 Oct 30 22:28 volumes
Dockerfile是镜像的描述文件,定义了如何构建Docker镜像。Dockerfile需要到docker网站去查看:
查看方法如下:
1 首先在网站上注册一个docker账号
2 在上面的搜索栏中输入hello-world
3 得到仓库中所有关于hello world的镜像,第一个就是我们下载的镜像
4 点击进入后,会发现如下的dockerfile链接
5 点击进入后跳转到github上的链接,可以看到hello-world的dockerfile写法
只有短短三条指令。
FROM scratch
此镜像是从白手起家,从
0
开始构建。COPY
hello /
将文件“hello”复制到镜像的根目录。CMD
["/hello"]
容器启动时,执行
/hello
镜像 hello-world 中就只有一个可执行文件 “hello”,其功能就是打印出 “Hello from Docker ......” 等信息。
/hello 就是文件系统的全部内容,连最基本的 /bin,/usr, /lib, /dev 都没有。 而/hello是根据hello.c编译而来的。可以点进去看下hello.c的内容,其实就是打印我们刚才执行docker run hello-world的内容。