Docker在CentOS 7 環境下的安裝及基本操做入門

時間 2019-11-09

標籤 docker centos 環境安裝基本入門欄目 Docker 简体版

原文原文鏈接

Docker 是一個開源的應用容器引擎，讓開發者能夠打包他們的應用以及依賴包到一個可移植的容器中，而後發佈到任何流行的 Linux 機器上，也能夠實現虛擬化。容器是徹底使用沙箱機制，相互之間不會有任何接口。php

此處主要講解在CentOS-7.3中安裝Docker環境python

一、安裝環境

CentOS Linux release 7.3.1611mysql

最新版本 Docker 19.03.1linux

二、Docker安裝步驟

注意 yum默認安裝的docker爲 1.13 版本，比較舊並且並非開源社區維護的版本，目前開源社區最新版本爲 19.03.1，社區分爲開源版本（docker-ce）和企業版本（docker-ee）。須要配置Docker官方源才能夠安裝最新版本，此處咱們安裝開源社區版本 docker-ce。sql

一、卸載舊版本的Docker

yum remove docker \
                  docker-common \
                  docker-selinux \
                  docker-engine

二、添加國內yuan

首先添加依賴，以下：docker

yum install -y yum-utils device-mapper-persistent-data lvm2

鑑於國內網絡問題，強烈建議使用國內源，以下：json

yum-config-manager \
    --add-repo \
    https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

安裝最新版docker，此處安裝社區開源版，以下：ubuntu

[root@localhost yum.repos.d]# yum install -y docker-ce

三、查看已安裝Docker的版本

執行以下命令可查看Docker版本：centos

docker -v

顯示版本信息以下：ruby

Docker version 19.03.1, build 74b1e89

四、啓動Docker服務並設置開機自啓動 docker

systemctl start docker && systemctl enable docker

五、執行測試hello-world鏡像

docker run hello-world

此時會出現沒法鏈接的狀況，由於Docker的官網被牆，默認的鏡像源地址沒法鏈接，會提示以下信息：

[root@localhost docker]# docker run hello-world
/usr/bin/docker-current: Cannot connect to the Docker daemon. Is the docker daemon running on this host?.
See '/usr/bin/docker-current run --help'.

解決此問題則須要修改鏡像源地址，修改 /etc/docker/daemon.json 文件，填寫Docker 官方中國區鏡像源地址，修改後/etc/docker/daemon.json 內容以下：

{
 "registry-mirrors": ["https://registry.docker-cn.com"]
}

也可以使用國內其餘Docker鏡像源地址

網易：http://hub-mirror.c.163.com
ustc：https://docker.mirrors.ustc.edu.cn

修改完成後從新執行測試hello-world鏡像，本地沒有的話則會從遠端鏡像庫下載，成功執行信息以下：

[root@localhost docker]# docker run hello-world
Unable to find image 'hello-world:latest' locally
Trying to pull repository docker.io/library/hello-world ... 
latest: Pulling from docker.io/library/hello-world
ca4f61b1923c: Pull complete 
Digest: sha256:445b2fe9afea8b4aa0b2f27fe49dd6ad130dfe7a8fd0832be5de99625dad47cd

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.
    (amd64)
 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/

看到此信息，則說明安裝Docker成功。

三、docker-compose 安裝

Compose 是一個用戶定義和運行多個容器的 Docker 應用程序。在 Compose 中你可使用 YAML 文件來配置你的應用服務。而後，只須要一個簡單的命令，就能夠建立並啓動你配置的全部服務。

使用 Compose 基本會有以下三步流程：

在 Dockfile 中定義你的應用環境，使其能夠在任何地方複製。
在 docker-compose.yml 中定義組成應用程序的服務，以便它們能夠在隔離的環境中一塊兒運行。
最後，運行dcoker-compose up，Compose 將啓動並運行整個應用程序。

安裝python-pip

yum -y install epel-release
yum -y install python-pip

安裝docker-compose

pip install docker-compose

裝完成後，執行查詢版本的命令，便可安裝docker-compose

[root@localhost ~]# docker-compose version
docker-compose version 1.21.2, build a133471
docker-py version: 3.3.0
CPython version: 2.7.5
OpenSSL version: OpenSSL 1.0.2k-fips  26 Jan 2017

四、Docker基本命令使用

須要首先清晰的認識Docker中鏡像與容器之間的關係，鏡像和容器就至關於Java中的類和對象的關係，鏡像是對容器的初始定義，運行鏡像以後會獲得容器，容器提交版本後會生成鏡像，Docker 的大部分操做都是針對容器的。

一、對鏡像的操做

一、查看本地鏡像

查看本地有哪些鏡像文件

[root@localhost docker]# docker images
REPOSITORY              TAG                 IMAGE ID            CREATED             SIZE
docker.io/hello-world   latest              f2a91732366c        4 weeks ago         1.848 kB

二、搜索鏡像文件

可經過搜索查找本身想要的鏡像，此處咱們搜索centos

[root@localhost docker]# docker search centos
INDEX       NAME                                         DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
docker.io   docker.io/centos                             The official build of CentOS.                   3893      [OK]       
docker.io   docker.io/ansible/centos7-ansible            Ansible on Centos7                              103                  [OK]
docker.io   docker.io/jdeathe/centos-ssh                 CentOS-6 6.9 x86_64 / CentOS-7 7.4.1708 x8...   90                   [OK]
docker.io   docker.io/consol/centos-xfce-vnc             Centos container with "headless" VNC sessi...   37                   [OK]
docker.io   docker.io/imagine10255/centos6-lnmp-php56    centos6-lnmp-php56                              35                   [OK]
docker.io   docker.io/tutum/centos                       Simple CentOS docker image with SSH access      34                   
docker.io   docker.io/gluster/gluster-centos             Official GlusterFS Image [ CentOS-7 +  Glu...   21                   [OK]
docker.io   docker.io/kinogmt/centos-ssh                 CentOS with SSH                                 18                   [OK]
docker.io   docker.io/centos/python-35-centos7           Platform for building and running Python 3...   14                   
docker.io   docker.io/openshift/base-centos7             A Centos7 derived base image for Source-To...   13                   
docker.io   docker.io/openshift/jenkins-2-centos7        A Centos7 based Jenkins v2.x image for use...   9                    
docker.io   docker.io/openshift/mysql-55-centos7         DEPRECATED: A Centos7 based MySQL v5.5 ima...   6                    
docker.io   docker.io/darksheer/centos                   Base Centos Image -- Updated hourly             3                    [OK]
docker.io   docker.io/openshift/ruby-20-centos7          DEPRECATED: A Centos7 based Ruby v2.0 imag...   3                    
docker.io   docker.io/blacklabelops/centos               CentOS Base Image! Built and Updates Daily!     1                    [OK]
docker.io   docker.io/indigo/centos-maven                Vanilla CentOS 7 with Oracle Java Developm...   1                    [OK]
docker.io   docker.io/miko2u/centos6                     CentOS6 日本語環境                                   1                    [OK]
docker.io   docker.io/openshift/php-55-centos7           DEPRECATED: A Centos7 based PHP v5.5 image...   1                    
docker.io   docker.io/pivotaldata/centos-gpdb-dev        CentOS image for GPDB development. Tag nam...   1                    
docker.io   docker.io/pivotaldata/centos-mingw           Using the mingw toolchain to cross-compile...   1                    
docker.io   docker.io/jameseckersall/sonarr-centos       Sonarr on CentOS 7                              0                    [OK]
docker.io   docker.io/openshift/wildfly-101-centos7      A Centos7 based WildFly v10.1 image for us...   0                    
docker.io   docker.io/pivotaldata/centos                 Base centos, freshened up a little with a ...   0                    
docker.io   docker.io/pivotaldata/centos-gcc-toolchain   CentOS with a toolchain, but unaffiliated ...   0                    
docker.io   docker.io/smartentry/centos                  centos with smartentry                          0                    [OK]

三、獲取遠程鏡像

可按照搜索結果名稱進行獲取，此處咱們獲取發佈版本Centos：The official build of CentOS

[root@localhost docker]# docker pull docker.io/centos
Using default tag: latest
Trying to pull repository docker.io/library/centos ... 
latest: Pulling from docker.io/library/centos
85432449fd0f: Pull complete 
Digest: sha256:3b1a65e9a05f0a77b5e8a698d3359459904c2a354dc3b25ae2e2f5c95f0b3667

四、運行鏡像

此處運行剛纔獲取的鏡像，鏡像運行以後成爲容器。

[root@localhost docker]# docker run -i -t docker.io/centos /bin/bash
[root@d86eed7c4bf0 /]# ls
anaconda-post.log  bin  dev  etc  home  lib  lib64  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var

此時已進入鏡像文件內部，此時咱們能夠對此容器進行更改，好比在 /home目錄下建立test.txt文件，內容爲 Hello my test file ! 。

五、退出（關閉）鏡像

[root@d86eed7c4bf0 /]# exit   
exit
[root@localhost docker]#

exit 命令會退出容器而且關閉容器，若是隻須要退出容器但不須要關閉則可按快捷鍵：Ctrl+P+Q

六、提交容器成爲鏡像

此處定義提交的容器的Tab爲 v1.1

[zhpt@localhost ~]$ docker commit -m ="Commit message" -a="Author" 22fd7c4c0668 docker.io/centos:v1.1
sha256:acef7126a6ac4e5abd3acfcd92655d1e41a45b9cc57b7d60eea7d75dc175667e

但是用 docker images 命令查看新提交的鏡像，以下：

[zhpt@localhost ~]$ docker images
REPOSITORY              TAG                 IMAGE ID            CREATED             SIZE
docker.io/centos        v1.1                acef7126a6ac        4 minutes ago       271.3 MB
docker.io/centos        latest              3fa822599e10        2 weeks ago         203.5 MB
docker.io/hello-world   latest              f2a91732366c        4 weeks ago         1.848 kB

七、刪除鏡像文件

刪除剛纔新提交的鏡像文件：docker.io/centos:v1.1

[zhpt@localhost ~]$ docker rmi docker.io/centos:v1.1
Untagged: docker.io/centos:v1.1
Deleted: sha256:acef7126a6ac4e5abd3acfcd92655d1e41a45b9cc57b7d60eea7d75dc175667e
Deleted: sha256:47744657ffff5c29bc5f73c0bc8ad9677688a50d89dda5777ef7467603fe2469
[zhpt@localhost ~]$ docker images
REPOSITORY              TAG                 IMAGE ID            CREATED             SIZE
docker.io/centos        latest              3fa822599e10        2 weeks ago         203.5 MB
docker.io/hello-world   latest              f2a91732366c        4 weeks ago         1.848 kB

二、對容器的操做

一、查看正在運行的鏡像

在鏡像運行後，關閉以前能夠查看正在運行的鏡像

[zhpt@localhost ~]$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED              STATUS              PORTS               NAMES
d86eed7c4bf0        docker.io/centos    "/bin/bash"         About a minute ago   Up About a minute                       elated_wescoff

二、中止正在執行的容器

[zhpt@localhost ~]$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
d86eed7c4bf0        docker.io/centos    "/bin/bash"         15 hours ago        Up 4 minutes                            elated_wescoff
[zhpt@localhost ~]$ docker kill d86eed7c4bf0
d86eed7c4bf0
[zhpt@localhost ~]$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
[zhpt@localhost ~]$

也可中止全部正在執行的容器

[zhpt@localhost ~]$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
d86eed7c4bf0        docker.io/centos    "/bin/bash"         15 hours ago        Up 2 minutes                            elated_wescoff
[zhpt@localhost ~]$ docker kill $(docker ps -q)
d86eed7c4bf0
[zhpt@localhost ~]$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
[zhpt@localhost ~]$

三、刪除已經中止的容器

只可刪除已經中止的容器，正在運行的容器是沒法刪除的。

[zhpt@localhost ~]$ docker rm 22fd7c4c0668
22fd7c4c0668
[zhpt@localhost ~]$ docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                         PORTS               NAMES
d86eed7c4bf0        docker.io/centos    "/bin/bash"         39 minutes ago      Exited (127) 38 minutes ago                        elated_wescoff
bda7d545ac4c        docker.io/centos    "/bin/bash"         2 hours ago         Exited (0) About an hour ago                       clever_mestorf
e1c6121e4845        hello-world         "/hello"            2 hours ago         Exited (0) 2 hours ago                             suspicious_ardinghelli

刪除全部已經中止的容器

[root@localhost zhpt]# docker rm $(docker ps -a -q)
2853ae52f76d
5c721cd6810b
fd2123aa64a2
84a6405887b4
bda7d545ac4c
e1c6121e4845

四、啓動已經中止的容器

[zhpt@localhost ~]$ docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                        PORTS               NAMES
d86eed7c4bf0        docker.io/centos    "/bin/bash"         15 hours ago        Exited (137) 47 seconds ago                       elated_wescoff
bda7d545ac4c        docker.io/centos    "/bin/bash"         17 hours ago        Exited (0) 16 hours ago                           clever_mestorf
e1c6121e4845        hello-world         "/hello"            17 hours ago        Exited (0) 6 minutes ago                          suspicious_ardinghelli
[zhpt@localhost ~]$ docker start -i d86eed7c4bf0
[root@d86eed7c4bf0 /]#

五、對容器重命名

由於容器的ID是隨機碼，而容器的名字又是看似無心義的命名，咱們可使用命令重命名，可以使用新名稱對容器進行操做。

[zhpt@localhost ~]$ docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                       PORTS               NAMES
d86eed7c4bf0        docker.io/centos    "/bin/bash"         15 hours ago        Exited (137) 4 minutes ago                       elated_wescoff
bda7d545ac4c        docker.io/centos    "/bin/bash"         17 hours ago        Exited (0) 16 hours ago                          clever_mestorf
e1c6121e4845        hello-world         "/hello"            17 hours ago        Exited (0) 14 minutes ago                        suspicious_ardinghelli
[zhpt@localhost ~]$ docker rename elated_wescoff my_centos
[zhpt@localhost ~]$ docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                       PORTS               NAMES
d86eed7c4bf0        docker.io/centos    "/bin/bash"         15 hours ago        Exited (137) 4 minutes ago                       my_centos
bda7d545ac4c        docker.io/centos    "/bin/bash"         17 hours ago        Exited (0) 16 hours ago                          clever_mestorf
e1c6121e4845        hello-world         "/hello"            17 hours ago        Exited (0) 14 minutes ago                        suspicious_ardinghelli
[zhpt@localhost ~]$ docker start -i my_centos 
[root@d86eed7c4bf0 /]#

六、進入正在運行的容器

[zhpt@localhost ~]$ docker start -i my_centos 
[root@d86eed7c4bf0 /]# [zhpt@localhost ~]$ 
[zhpt@localhost ~]$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
d86eed7c4bf0        docker.io/centos    "/bin/bash"         16 hours ago        Up 14 minutes                           my_centos
[zhpt@localhost ~]$ docker attach d86eed7c4bf0
[root@d86eed7c4bf0 /]#

推薦使用以下方式：

[root@localhost es]# docker exec -it 0f19337a8ac9 /bin/bash
root@0f19337a8ac9:/usr/src/app#

三、其餘經常使用命令

一、導出鏡像爲文件

docker save 2f8543cab450 > /root/images/elasticsearch-head.tar

二、導入文件爲鏡像

docker load < /home/zhpt/es/elasticsearch-head.tar

三、重命名鏡像

docker tag 2f8543cab450 elasticsearch-head:v1

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