Docker還允許我們在隔離的容器中安裝任何作業系統。在下面的例子中，將演示如何在Docker中安裝Ubuntu系統。
1.建立一個目錄用來組織安裝的作業系統檔案。
yiibai@ubuntu:~$ mkdir -p /home/yiibai/docker/ubuntu-in-docker
2.進入工作目錄
yiibai@ubuntu:~$ cd /home/yiibai/docker/ubuntu-in-docker
3.建立一個 Dockerfile 檔案
在檔案中，只使用一個將從Docker中轉站拉出Ubuntu映像的指令。
FROM ubuntu
4.建立Docker映像
yiibai@ubuntu:~/docker/ubuntu-in-docker$ sudo docker build -t ubuntu-in-doker .
[sudo] password for yiibai:
Sending build context to Docker daemon 2.048kB
Step 1/1 : FROM ubuntu
latest: Pulling from library/ubuntu
Digest: sha256:ea1d854d38be82f54d39efe2c67000bed1b03348bcc2f3dc094f260855dff368
Status: Downloaded newer image for ubuntu:latest
---> 7b9b13f7b9c0
Successfully built 7b9b13f7b9c0
Successfully tagged ubuntu-in-doker:latest
yiibai@ubuntu:~/docker/ubuntu-in-docker$
5.執行Docker映像
現在，建立這個Ubuntu系統的Docker映像，以下命令用於建立Docker映像。
yiibai@ubuntu:~/docker/ubuntu-in-docker$ sudo docker run -td ubuntu
e36afad81d32340536f01898fd81ad33151ee765a26ef635e010b26f12b30f3a
yiibai@ubuntu:~/docker/ubuntu-in-docker$
6.檢視當前執行的 Docker映像
使用以下命令檢視所有正在執行的Docker容器。
yiibai@ubuntu:~/docker/ubuntu-in-docker$ sudo docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e36afad81d32 ubuntu "/bin/bash" 21 seconds ago Up 20 seconds admiring_bardeen
cf86a1188de2 ruby-app "ruby index.rb" 9 days ago Exited (0) 9 days ago angry_bhaskara
be0eed0c9c84 perl-app "perl index.pl" 9 days ago Exited (0) 9 days ago trusting_snyder
b89d59fd1d2d 774aa9644b86 "perl index.pl" 9 days ago Exited (0) 9 days ago competent_wing
05360c63fbc0 774aa9644b86 "perl index.pl" 9 days ago Exited (0) 9 days ago elegant_ardinghelli
38421563452a scala-app "scala /home/yiiba..." 9 days ago Exited (0) 9 days ago fervent_curie
14d84bd35af1 3b6d4c56eefe "java" 9 days ago Exited (1) 9 days ago stupefied_engelbart
cee6b601cdf2 3b6d4c56eefe "java" 9 days ago Exited (1) 9 days ago wizardly_pasteur
20e511a331ff 1562335544a3 "java" 9 days ago Exited (1) 9 days ago trusting_stallman
ad7e2665f4f2 1562335544a3 "java" 9 days ago Exited (1) 9 days ago zen_payne
d480e715d048 1562335544a3 "java" 9 days ago Exited (1) 9 days ago vigorous_leavitt
0a48d6a92b74 4f6372b49671 "/bin/bash" 9 days ago Exited (0) 9 days ago focused_curie
a442819877c2 4f6372b49671 "/bin/bash" 9 days ago Exited (0) 9 days ago vigilant_lumiere
a8ce493bd731 4f6372b49671 "/bin/bash" 9 days ago Exited (0) 9 days ago nifty_meninsky
c14344cddb6d 4f6372b49671 "/bin/bash" 9 days ago Exited (0) 9 days ago brave_snyder
432b82d9a89b 1d786cf20101 "/bin/bash" 9 days ago Exited (0) 9 days ago sad_kirch
0f7380223ace 1d786cf20101 "/bin/bash" 9 days ago Exited (0) 9 days ago practical_nightingale
693b0835b814 python-app "python /src/index.py" 9 days ago Exited (0) 9 days ago frosty_mclean
0db2a61f1ad0 php-app "docker-php-entryp..." 11 days ago Exited (0) 9 days ago dazzling_joliot
12d76c89d7de 0420419feb44 "docker-php-entryp..." 11 days ago Exited (0) 11 days ago priceless_swanson
ad76da990bc0 0420419feb44 "docker-php-entryp..." 11 days ago Exited (0) 11 days ago jovial_mcnulty
8ad82d85154a 0420419feb44 "docker-php-entryp..." 11 days ago Exited (0) 11 days ago friendly_gates
55d0303126a1 ca59a5a4f3fb "docker-php-entryp..." 11 days ago Exited (0) 11 days ago blissful_raman
f392d8d38d0e c2e626f9d9c6 "docker-php-entryp..." 11 days ago Exited (0) 11 days ago determined_nightingale
c59065c26414 c2e626f9d9c6 "docker-php-entryp..." 11 days ago Exited (0) 11 days ago dreamy_goldwasser
f0abe5b8969f c2e626f9d9c6 "docker-php-entryp..." 11 days ago Exited (0) 11 days ago eloquent_payne
c7772607fcf9 java-app "java Hello" 12 days ago Exited (0) 12 days ago awesome_lewin
30ef57b84864 hello-world "/hello" 12 days ago Exited (0) 12 days ago frosty_benz
0415f34bb21e hello-world "/hello" 12 days ago Exited (0) 12 days ago zen_lalande
yiibai@ubuntu:~/docker/ubuntu-in-docker$
7.進入Docker容器
可以進入執行容器，並可以檢查容器內的檔案和應用程式。
yiibai@ubuntu:~/docker/ubuntu-in-docker$ sudo docker exec -it e36afad81d32 bash
8.請參閱Ubuntu作業系統目錄結構
進入後，如下所示 -
yiibai@ubuntu:~/docker/ubuntu-in-docker$ sudo docker exec -it e36afad81d32 bash
root@e36afad81d32:/# pwd
/
root@e36afad81d32:/#
9.執行命令
root@e36afad81d32:/# apt-get update
Get:1 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]
Get:2 http://security.ubuntu.com/ubuntu xenial-security/universe Sources [39.4 kB]
Get:3 http://archive.ubuntu.com/ubuntu xenial InRelease [247 kB]
Get:4 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages [355 kB]
Get:5 http://security.ubuntu.com/ubuntu xenial-security/restricted amd64 Packages [12.8 kB]
Get:6 http://security.ubuntu.com/ubuntu xenial-security/universe amd64 Packages [170 kB]
Get:7 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB]
0% [7 InRelease 55.6 kB/102 kB 54%] [6 Packages 129 kB/170 kB 76%]
....