2018年第48周-centos7下的docker的安裝及經常使用命令

docker玩過不少次,但每次都是從零開始,因此此次而打算記錄下來,方便後面查詢。
docker的技術基礎是LXC虛擬化技術,虛擬化技術有不少,有硬件層面和軟件層面的,我在
2018年第13周-虛擬化技術理解大概有描述。其中LXC就是軟件層面的虛擬化技術。其內存利用率很高,這是由於全部虛擬機(在docker裏叫Container)都共享宿主的操做系統實例,,不存在因爲運行多個操做系統實例所形成的性能損耗。下圖是docker與其餘虛擬技術的對比圖。
圖片描述
Docker的目標是「Build, Ship and Run Any App, Anywhere」,基於這個目標,將你須要發佈的應用組件及須要的環境配置都封裝成一個image(鏡像),而後基於鏡像建立Container(容器)並啓動運行。這樣就能夠達到組建級別的一次封裝,屢次運行。是否是跟JVM很像,一次編譯,多處運行。python

安裝準備

卸載歷史版本

歷史本版的Docker可能被叫爲docker或docker-engine. 若是它們有安裝 ,卸載它以及它們的依賴. 命令以下:linux

$ sudo yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-selinux \
                  docker-engine-selinux \
                  docker-engine

/var/lib/docker/目錄裏的內容將被保留, 以及images, containers, volumes, 和networks將會被保留.
Docker CE包如今叫 docker-cedocker

安裝Docker CE

你能夠從不少地方安裝Docker CE, 這取決於你的需求:json

  • 不少用戶設置Docker的yum倉庫, 而後安裝docker, 這樣容易安裝和升級. 推薦此方法.
  • 有些用戶下載ROM包, 並手工安裝和手工管理升級. 這種方法對於那些沒法連上網的服務器是頗有用的.
  • 在測試和開發環境, 有些用戶選擇自動方便的腳本來安裝docker.

從倉庫安裝

在安裝Docker CE以前, 你須要設置Docker的yum倉庫. 而後在安裝.segmentfault

設置倉庫

  1. 安裝須要的包. yum-utils提供yum-config-manager工具, devicemapper存儲驅動則須要device-mapper-persistent-data和lvm2
$ sudo yum install -y yum-utils \
  device-mapper-persistent-data \
  lvm2

我centos7系統安裝時選擇的SOFTWARE SELECTION是Infrastuctue Server (Server for operating network infrastuctue Server)centos

[root@amd usb]# sudo yum install -y yum-utils \
>   device-mapper-persistent-data \
>   lvm2
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: mirror.lzu.edu.cn
 * extras: mirrors.zju.edu.cn
 * updates: mirrors.zju.edu.cn
Package yum-utils-1.1.31-46.el7_5.noarch already installed and latest version
Package device-mapper-persistent-data-0.7.3-3.el7.x86_64 already installed and latest version
Package 7:lvm2-2.02.177-4.el7.x86_64 already installed and latest version
Nothing to do
  1. 使用如下命令設置stable倉庫, 就算你想安裝edgetest倉庫, 也仍是得安裝stable倉庫.
sudo yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo
[root@amd usb]# sudo yum-config-manager \
>     --add-repo \
>     https://download.docker.com/linux/centos/docker-ce.repo
Loaded plugins: fastestmirror, langpacks
adding repo from: https://download.docker.com/linux/centos/docker-ce.repo
grabbing file https://download.docker.com/linux/centos/docker-ce.repo to /etc/yum.repos.d/docker-ce.repo
repo saved to /etc/yum.repos.d/docker-ce.repo
  1. 可選: 啓動edgetest倉庫, 這些倉庫都是包含在docker.repo文件, 只是默認是關閉的.
$ sudo yum-config-manager --enable docker-ce-edge
$ sudo yum-config-manager --enable docker-ce-test

經過yum-config-manager命令關閉edgetest倉庫.bash

sudo yum-config-manager --disable docker-ce-edge

安裝Docker CE

  1. 安裝最新版本的Docker CE, 或者參考下一步可指定版本:
sudo yum install docker-ce

若是須要確認GPG key, 確認fingerprint是否匹配060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35, 匹配上了則確認服務器

多個docker庫的狀況下
若是你有多個docker庫啓用了, 並且安裝或升級時不指定版本, 那麼yum install或yum update命令則總會安裝儘量高的版本, 這也許不符合你穩定的要求.
到此位置, docker已經安裝, 但還未啓動. Linux的docker group也建立了, 但沒有users在這組裏.
安裝過程:
[root@amd ~]# sudo yum install docker-ce 
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
 * base: mirror.lzu.edu.cn
 * extras: mirrors.zju.edu.cn
 * updates: mirrors.zju.edu.cn
base                                                                                                                                                                                          | 3.6 kB  00:00:00     
docker-ce-stable                                                                                                                                                                              | 2.9 kB  00:00:00     
epel                                                                                                                                                                                          | 3.2 kB  00:00:00     
extras                                                                                                                                                                                        | 3.4 kB  00:00:00     
updates                                                                                                                                                                                       | 3.4 kB  00:00:00     
(1/2): epel/x86_64/updateinfo                                                                                                                                                                 | 935 kB  00:00:05     
(2/2): epel/x86_64/primary                                                                                                                                                                    | 3.6 MB  00:00:14     
epel                                                                                                                                                                                                     12742/12742
Resolving Dependencies
--> Running transaction check
---> Package docker-ce.x86_64 0:18.06.1.ce-3.el7 will be installed
--> Processing Dependency: container-selinux >= 2.9 for package: docker-ce-18.06.1.ce-3.el7.x86_64
--> Processing Dependency: libcgroup for package: docker-ce-18.06.1.ce-3.el7.x86_64
--> Processing Dependency: libltdl.so.7()(64bit) for package: docker-ce-18.06.1.ce-3.el7.x86_64
--> Running transaction check
---> Package container-selinux.noarch 2:2.68-1.el7 will be installed
--> Processing Dependency: policycoreutils-python for package: 2:container-selinux-2.68-1.el7.noarch
---> Package libcgroup.x86_64 0:0.41-15.el7 will be installed
---> Package libtool-ltdl.x86_64 0:2.4.2-22.el7_3 will be installed
--> Running transaction check
---> Package policycoreutils-python.x86_64 0:2.5-22.el7 will be installed
--> Processing Dependency: setools-libs >= 3.3.8-2 for package: policycoreutils-python-2.5-22.el7.x86_64
--> Processing Dependency: libsemanage-python >= 2.5-9 for package: policycoreutils-python-2.5-22.el7.x86_64
--> Processing Dependency: audit-libs-python >= 2.1.3-4 for package: policycoreutils-python-2.5-22.el7.x86_64
--> Processing Dependency: python-IPy for package: policycoreutils-python-2.5-22.el7.x86_64
--> Processing Dependency: libqpol.so.1(VERS_1.4)(64bit) for package: policycoreutils-python-2.5-22.el7.x86_64
--> Processing Dependency: libqpol.so.1(VERS_1.2)(64bit) for package: policycoreutils-python-2.5-22.el7.x86_64
--> Processing Dependency: libapol.so.4(VERS_4.0)(64bit) for package: policycoreutils-python-2.5-22.el7.x86_64
--> Processing Dependency: checkpolicy for package: policycoreutils-python-2.5-22.el7.x86_64
--> Processing Dependency: libqpol.so.1()(64bit) for package: policycoreutils-python-2.5-22.el7.x86_64
--> Processing Dependency: libapol.so.4()(64bit) for package: policycoreutils-python-2.5-22.el7.x86_64
--> Running transaction check
---> Package audit-libs-python.x86_64 0:2.8.1-3.el7_5.1 will be installed
---> Package checkpolicy.x86_64 0:2.5-6.el7 will be installed
---> Package libsemanage-python.x86_64 0:2.5-11.el7 will be installed
---> Package python-IPy.noarch 0:0.75-6.el7 will be installed
---> Package setools-libs.x86_64 0:3.3.8-2.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

=====================================================================================================================================================================================================================
 Package                                                   Arch                                      Version                                               Repository                                           Size
=====================================================================================================================================================================================================================
Installing:
 docker-ce                                                 x86_64                                    18.06.1.ce-3.el7                                      docker-ce-stable                                     41 M
Installing for dependencies:
 audit-libs-python                                         x86_64                                    2.8.1-3.el7_5.1                                       updates                                              75 k
 checkpolicy                                               x86_64                                    2.5-6.el7                                             base                                                294 k
 container-selinux                                         noarch                                    2:2.68-1.el7                                          extras                                               36 k
 libcgroup                                                 x86_64                                    0.41-15.el7                                           base                                                 65 k
 libsemanage-python                                        x86_64                                    2.5-11.el7                                            base                                                112 k
 libtool-ltdl                                              x86_64                                    2.4.2-22.el7_3                                        base                                                 49 k
 policycoreutils-python                                    x86_64                                    2.5-22.el7                                            base                                                454 k
 python-IPy                                                noarch                                    0.75-6.el7                                            base                                                 32 k
 setools-libs                                              x86_64                                    3.3.8-2.el7                                           base                                                619 k

Transaction Summary
=====================================================================================================================================================================================================================
Install  1 Package (+9 Dependent packages)

Total size: 42 M
Installed size: 46 M
Is this ok [y/d/N]: y
Downloading packages:
warning: /var/cache/yum/x86_64/7/docker-ce-stable/packages/docker-ce-18.06.1.ce-3.el7.x86_64.rpm: Header V4 RSA/SHA512 Signature, key ID 621e9f35: NOKEY
Retrieving key from https://download.docker.com/linux/centos/gpg
Importing GPG key 0x621E9F35:
 Userid     : "Docker Release (CE rpm) <docker@docker.com>"
 Fingerprint: 060a 61c5 1b55 8a7f 742b 77aa c52f eb6b 621e 9f35
 From       : https://download.docker.com/linux/centos/gpg
Is this ok [y/N]: y
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : libcgroup-0.41-15.el7.x86_64                                                                                                                                                                     1/10 
  Installing : audit-libs-python-2.8.1-3.el7_5.1.x86_64                                                                                                                                                         2/10 
  Installing : setools-libs-3.3.8-2.el7.x86_64                                                                                                                                                                  3/10 
  Installing : libtool-ltdl-2.4.2-22.el7_3.x86_64                                                                                                                                                               4/10 
  Installing : python-IPy-0.75-6.el7.noarch                                                                                                                                                                     5/10 
  Installing : checkpolicy-2.5-6.el7.x86_64                                                                                                                                                                     6/10 
  Installing : libsemanage-python-2.5-11.el7.x86_64                                                                                                                                                             7/10 
  Installing : policycoreutils-python-2.5-22.el7.x86_64                                                                                                                                                         8/10 
  Installing : 2:container-selinux-2.68-1.el7.noarch                                                                                                                                                            9/10 
setsebool:  SELinux is disabled.
  Installing : docker-ce-18.06.1.ce-3.el7.x86_64                                                                                                                                                               10/10 
  Verifying  : libcgroup-0.41-15.el7.x86_64                                                                                                                                                                     1/10 
  Verifying  : docker-ce-18.06.1.ce-3.el7.x86_64                                                                                                                                                                2/10 
  Verifying  : policycoreutils-python-2.5-22.el7.x86_64                                                                                                                                                         3/10 
  Verifying  : libsemanage-python-2.5-11.el7.x86_64                                                                                                                                                             4/10 
  Verifying  : 2:container-selinux-2.68-1.el7.noarch                                                                                                                                                            5/10 
  Verifying  : checkpolicy-2.5-6.el7.x86_64                                                                                                                                                                     6/10 
  Verifying  : python-IPy-0.75-6.el7.noarch                                                                                                                                                                     7/10 
  Verifying  : libtool-ltdl-2.4.2-22.el7_3.x86_64                                                                                                                                                               8/10 
  Verifying  : setools-libs-3.3.8-2.el7.x86_64                                                                                                                                                                  9/10 
  Verifying  : audit-libs-python-2.8.1-3.el7_5.1.x86_64                                                                                                                                                        10/10 

Installed:
  docker-ce.x86_64 0:18.06.1.ce-3.el7                                                                                                                                                                                

Dependency Installed:
  audit-libs-python.x86_64 0:2.8.1-3.el7_5.1    checkpolicy.x86_64 0:2.5-6.el7                container-selinux.noarch 2:2.68-1.el7    libcgroup.x86_64 0:0.41-15.el7       libsemanage-python.x86_64 0:2.5-11.el7   
  libtool-ltdl.x86_64 0:2.4.2-22.el7_3          policycoreutils-python.x86_64 0:2.5-22.el7    python-IPy.noarch 0:0.75-6.el7           setools-libs.x86_64 0:3.3.8-2.el7   

Complete!
  1. 指定版本安裝Docker CE, 首先先列出倉庫有哪些docker-ce版本, 而後在選擇安裝

a. 列出並排序有哪些版本在倉庫裏, 如下是例子, 從高級到低級.網絡

[root@amd ~]#  yum list docker-ce --showduplicates | sort -r
 * updates: mirrors.zju.edu.cn
Loading mirror speeds from cached hostfile
Loaded plugins: fastestmirror, langpacks
Installed Packages
 * extras: mirrors.zju.edu.cn
docker-ce.x86_64            18.06.1.ce-3.el7                   docker-ce-stable 
docker-ce.x86_64            18.06.1.ce-3.el7                   @docker-ce-stable
docker-ce.x86_64            18.06.0.ce-3.el7                   docker-ce-stable 
docker-ce.x86_64            18.03.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            18.03.0.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.12.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.12.0.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.09.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.09.0.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.06.2.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.06.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.06.0.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.03.3.ce-1.el7                   docker-ce-stable 
docker-ce.x86_64            17.03.2.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.03.1.ce-1.el7.centos            docker-ce-stable 
docker-ce.x86_64            17.03.0.ce-1.el7.centos            docker-ce-stable 
 * base: mirror.lzu.edu.cn
Available Packages

這列表內容取決於哪一個倉庫被啓動, 而且指定了你CentOS版本(在這例子裏是.el7)
b. 安裝指定版本, 需指定全限定包名, 也就是包名(docker-ce)加版本字符串(第2列), 以橫槓(-)隔開, 例如: docker-ce-18.03.0.ceapp

sudo yum install docker-ce-<VERSION STRING>

Dokcer

到此位置, docker已經安裝, 但還未啓動. Linux的docker group也建立了, 但沒有users在這組裏.

  1. 啓動Docker
$ sudo systemctl start docker
  1. 驗證Docker是否安裝正確, 咱們運行個hello-world鏡像
sudo docker run hello-world

此命令會下載一個test鏡像, 而後運行在一個容器裏, 當容器運行時, 它會輸出信息, 而後退出.

Docker CE已經安裝而且運行着, 你須要用sudo在運行Docker. 能夠繼續教程Linux postinstall 來運行沒有權限的用戶運行Docker命令.

升級Docker-CE

就在yum中直接選擇新版本安裝便可

docker操做

查詢鏡像

docker search centos

下載鏡像

docker pull centos

本地鏡像列表

docker images

啓動centos並進入bash

docker run -ti centos /bin/bash

查看全部容器狀況

docker ps -a

使用宿主的全部網絡信息的啓動docker

docker run -tid  --name  can_download --net host centos /bin/bash

建立bridge的網關

docker run -tid  --name my-net-centos --network my-net centos /bin/bash

指定bridge的網關

 鏈接後臺運行的container

docker exec -it my-net-centos /bin/bash

宿主與container傳輸文件

docker cp jdk-8u172-linux-x64.tar.gz f858312b67c20f1ff5303ae8f8333133c8791d434ee30c0e3395ccfb6b345d4f:/root/jdk-8u172-linux-x64.tar.gz

TroubleShoot

管理權限

nescafe@nescafe-PC:~$ docker images
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.38/images/json: dial unix /var/run/docker.sock: connect: permission denied

緣由

摘自docker mannual上的一段話

Manage Docker as a non-root user
The docker daemon binds to a Unix socket instead of a TCP port. By default that Unix socket is owned by the user root and other users can only access it using sudo. The docker daemon always runs as the root user.
If you don’t want to use sudo when you use the docker command, create a Unix group called docker and add users to it. When the docker daemon starts, it makes the ownership of the Unix socket read/writable by the docker group.
大概的意思就是:docker進程使用Unix Socket而不是TCP端口。而默認狀況下,Unix socket屬於root用戶,須要root權限才能訪問。

解決方法1

使用sudo獲取管理員權限,運行docker命令

解決方法2

docker守護進程啓動的時候,會默認賦予名字爲docker的用戶組讀寫Unix socket的權限,所以只要建立docker用戶組,並將當前用戶加入到docker用戶組中,那麼當前用戶就有權限訪問Unix socket了,進而也就能夠執行docker相關命令

sudo groupadd docker     #添加docker用戶組
sudo gpasswd -a $USER docker     #將登錄用戶加入到docker用戶組中
newgrp docker     #更新用戶組
docker ps    #測試docker命令是否可使用sudo正常使用
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