docker（3）快速搭建centos7-python3.6环境
前言
当我们在一台电脑上搭建了python3.6的环境，下次换台电脑，又得重新搭建一次，设置环境变量等操作。
好不容易安装好，一会提示pip不是内部或外部命令，一会又提示pip: command not found,想死的心都有了。
搭建环境是真的麻烦，不弄好又不行，从今天开始学好docker，环境问题从此和你说再见
docker search搜索镜像
docker search : 从Docker Hub(https://hub.docker.com)中搜索指定的镜像
比如我这里搜索一个基于centos7环境安装的python3.6版本
[root@jkc ~]# docker search python
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
python Python is an interpreted, interactive, objec… 5776 [OK]
django Django is a free web application framework, … 1040 [OK]
pypy PyPy is a fast, compliant alternative implem… 262 [OK]
nikolaik/python-nodejs Python with Node.js 57 [OK]
joyzoursky/python-chromedriver Python with Chromedriver, for running automa… 57 [OK]
arm32v7/python Python is an interpreted, interactive, objec… 54
circleci/python Python is an interpreted, interactive, objec… 42
centos/python-35-centos7 Platform for building and running Python 3.5… 39
centos/python-36-centos7 Platform for building and running Python 3.6… 30
hylang Hy is a Lisp dialect that translates express… 29 [OK]
arm64v8/python Python is an interpreted, interactive, objec… 24
revolutionsystems/python Optimized Python Images 18
centos/python-27-centos7 Platform for building and running Python 2.7… 17
bitnami/python Bitnami Python Docker Image 10 [OK]
publicisworldwide/python-conda Basic Python environments with Conda. 6 [OK]
d3fk/python_in_bottle Simple python:alpine completed by Bottle+Req… 5 [OK]
dockershelf/python Repository for docker images of Python. Test… 5 [OK]
clearlinux/python Python programming interpreted language with… 4
i386/python Python is an interpreted, interactive, objec… 3
centos/python-34-centos7 Platform for building and running Python 3.4… 2
ppc64le/python Python is an interpreted, interactive, objec… 2
amd64/python Python is an interpreted, interactive, objec… 1
s390x/python Python is an interpreted, interactive, objec… 0
ccitest/python CircleCI test images for Python 0 [OK]
saagie/python Repo for python jobs 0
- NAME 镜像仓库名称
- DESCRIPTION 镜像描述信息
- STARS 镜像收藏数
- OFFICIAL 是否为docker官方发布的镜像
- AUTOMATED 是否为自动化构建的镜像
- 关于自动化构建，可以查看官方文档：https://docs.docker.com/docker-hub/builds/#how-automated-builds-work
下载pull镜像
上面找的想要下载的镜像centos/python-36-centos7,接下来下载到自己本地
如果下载速度缓慢，可以参考这篇博客https://www.cnblogs.com/jiakecong/p/14308660.html
docker pull centos/python-36-centos7
[root@jkc docker]# docker pull centos/python-36-centos7
Using default tag: latest
latest: Pulling from centos/python-36-centos7
75f829a71a1c: Pull complete
e2c4942f4189: Pull complete
f1498894b11c: Pull complete
da56c9694723: Pull complete
07fa76fc639e: Pull complete
abab42dfb7f7: Pull complete
dd73d54fbd62: Pull complete
25966a5cbd52: Pull complete
b947aec7d116: Pull complete
Digest: sha256:ac50754646f0d37616515fb30467d8743fb12954260ec36c9ecb5a94499447e0
Status: Downloaded newer image for centos/python-36-centos7:latest
docker.io/centos/python-36-centos7:latest
[root@jkc docker]#
安装其他python版本
如果有小伙伴想安装其他python版本，比如3.7或者3.8，去https://hub.docker.com搜索即可
进入后选择tags标签，进入找到想要的版本复制命令即可
docker images
使用docker images查看本地已经下载好的镜像
[root@jkc docker]# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
mysql 5.7 ae0658fdbad5 2 months ago 449MB
centos/python-36-centos7 latest 602660fa9b4e 4 months ago 650MB
[root@jkc docker]#
运行交互式的容器
Docker会在隔离的容器中运行进程。当运行docker run命令时，Docker会启动一个进程，并为这个进程分配其独占的文件系统、网络资源和以此进程为根进程的进程组。
在容器启动时，镜像可能已经定义了要运行的二进制文件、暴露的网络端口等，但是用户可以通过docker run命令重新定义
最基本的docker run命令的格式如下：
$ sudo docker run [OPTIONS] IMAGE[:TAG] [COMMAND] [ARG...]
比如我这里要启动centos7，进入交互模式，通过docker的两个参数 -i -t，让docker运行的容器实现"对话"的能力
- -t: 在新容器内指定一个伪终端或终端。
- -i: 允许你对容器内的标准输入 (STDIN) 进行交互
- centos/python-36-centos7：镜像名称
- /bin/bash：放在镜像名后的是命令，这里我们希望有个交互式 Shell，因此用的是 /bin/bash。
docker run -i -t centos/python-36-centos7 /bin/bash
进入centos终端后，进python交互环境打印"hello",最后用exit退出
[root@jkc docker]# docker run -i -t centos/python-36-centos7 /bin/bash
(app-root) python
Python 3.6.9 (default, Nov 11 2019, 11:24:16)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> print("hello")
hello
>>> exit()
(app-root)
后台模式启动
run加上-i -t是进交互模式，如果不想进交互模式直接执行脚本，可以直接使用run,比如echo "hello world",屏幕会输出"hello world"
docker run centos/python-36-centos7 /bin/echo "hello world"
如果不想在前台执行，一般我们运行环境会选择挂后台,加个-d 参数即可
[root@jkc docker]# docker run centos/python-36-centos7 /bin/echo "hello world"
hello world
[root@jkc docker]# docker run -d centos/python-36-centos7 /bin/echo "hello world"
8c7c7449d8596d0d2b7c6d5672ec68d9da73733984232377fb35b30b876faaf5
使用-d后台执行后，会发现下面多了一长串，这个就是容器的唯一id，可以通过这个id找到容器
docker ps查看容器
先run下 training/webapp
docker run -d -p 5000:5000 training/webapp python app.py
使用docker ps查看正在运行的容器
[root@jkc docker]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a67640969dd9 training/webapp "python app.py" 31 seconds ago Up 31 seconds 0.0.0.0:5000->5000/tcp admiring_mahavira
[root@jkc docker]#
上面的echo "hello world"只是一个很简单的输出指令，执行完就关闭了，所以ps查找正在运行的查不到，可以加个-a参数,显示所有的容器，包括未运行的
ps 查找参数相关语法
- -a :显示所有的容器，包括未运行的。
- -f :根据条件过滤显示的内容。
- --format :指定返回值的模板文件。
- -l :显示最近创建的容器。
- -n :列出最近创建的n个容器。
- --no-trunc :不截断输出。
- -q :静默模式，只显示容器编号。
- -s :显示总的文件大小。
docker ps -a
[root@jkc docker]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a67640969dd9 training/webapp "python app.py" 2 minutes ago Up 2 minutes 0.0.0.0:5000->5000/tcp admiring_mahavira
8c7c7449d859 centos/python-36-centos7 "container-entrypoin…" 4 minutes ago Exited (0) 4 minutes ago nostalgic_mccarthy
9df0d290b4e6 centos/python-36-centos7 "container-entrypoin…" 5 minutes ago Exited (0) 5 minutes ago wonderful_cohen
c01f59e13a3a centos/python-36-centos7 "container-entrypoin…" 5 minutes ago Exited (0) 5 minutes ago wonderful_hamilton
3c2d40166a8f centos/python-36-centos7 "container-entrypoin…" 12 minutes ago Exited (0) 5 minutes ago pedantic_engelbart
713e29359fcd centos/python-36-centos7 "container-entrypoin…" 14 minutes ago Exited (0) 12 minutes ago priceless_allen
29980b073576 mysql:5.7 "docker-entrypoint.s…" 7 weeks ago Exited (0) 2 hours ago jkcmysql
[root@jkc docker]#
这样就能找到上面的容器id 8c7c7449d859 ,不过没那么长
docker logs查看日志
可以通过容器id去查运行的日志
docker logs [容器id]
[root@jkc docker]# docker logs 8c7c7449d859
hello world
[root@jkc docker]#
也可以通过容器的名称去查看，注意这里是容器的名称，不是镜像名称。容器名称是系统自动分配的，如上面的最后一项NAMES 值hopeful_poincare
[root@jkc docker]# docker logs nostalgic_mccarthy
hello world
-f: 让 docker logs 像使用 tail -f 一样来输出容器内部的标准输出。
[root@jkc docker]# docker logs -f 8c7c7449d859
hello world
停止容器
可以用ps查看正在运行的容器
docker ps
[root@jkc docker]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a67640969dd9 training/webapp "python app.py" 9 minutes ago Up 9 minutes 0.0.0.0:5000->5000/tcp admiring_mahavira
停止容器的话，可以用docker stop容器的id或者容器NAME名称
docker stop a67640969dd9
或者提供容器名称admiring_mahavira来停止
docker stop admiring_mahavira
启动容器
docker start 容器id
[root@jkc docker]# docker start a67640969dd9
a67640969dd9
[root@jkc docker]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a67640969dd9 training/webapp "python app.py" 13 minutes ago Up 6 seconds 0.0.0.0:5000->5000/tcp admiring_mahavira
正在运行的容器，可以使用 docker restart 命令来重启
[root@jkc docker]# docker restart a67640969dd9
a67640969dd9
进入容器
在使用 -d 参数时，容器启动后会进入后台。此时想要进入容器，可以通过以下指令进入：
- docker attach
- docker exec：推荐大家使用 docker exec 命令，因为此退出容器终端，不会导致容器的停止。
attach 命令
下面演示了使用 docker attach 命令。
docker attach 1e560fca3906
注意： 如果从这个容器退出，会导致容器的停止。
exec 命令
下面演示了使用 docker exec 命令。
[root@jkc easymock]# docker exec -it 25743368a66d /bin/bash
[root@jkc easymock]# docker exec -it 25743368a66d /bin/bash
root@25743368a66d:/opt/webapp# exit
exit
[root@jkc easymock]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
25743368a66d training/webapp "python app.py" 4 minutes ago Up 4 minutes 5000/tcp keen_aryabhata
注意： 如果从这个容器退出，容器不会停止，这就是为什么推荐大家使用 docker exec 的原因。
更多参数说明请使用 docker exec --help 命令查看。
删除容器
使用 docker rm 命令来删除不需要的容器
[root@jkc docker]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a67640969dd9 training/webapp "python app.py" 14 minutes ago Up About a minute 0.0.0.0:5000->5000/tcp admiring_mahavira
8c7c7449d859 centos/python-36-centos7 "container-entrypoin…" 17 minutes ago Exited (0) 17 minutes ago nostalgic_mccarthy
9df0d290b4e6 centos/python-36-centos7 "container-entrypoin…" 18 minutes ago Exited (0) 18 minutes ago wonderful_cohen
c01f59e13a3a centos/python-36-centos7 "container-entrypoin…" 18 minutes ago Exited (0) 18 minutes ago wonderful_hamilton
3c2d40166a8f centos/python-36-centos7 "container-entrypoin…" 25 minutes ago Exited (0) 18 minutes ago pedantic_engelbart
713e29359fcd centos/python-36-centos7 "container-entrypoin…" 26 minutes ago Exited (0) 25 minutes ago priceless_allen
29980b073576 mysql:5.7 "docker-entrypoint.s…" 7 weeks ago Exited (0) 3 hours ago jkcmysql
[root@jkc docker]# docker rm 8c7c7449d859
8c7c7449d859
[root@jkc docker]# docker rm 9df0d290b4e6
9df0d290b4e6
[root@jkc docker]# docker rm admiring_mahavira
Error response from daemon: You cannot remove a running container a67640969dd99d6f26810857d29dd47a43088ea927c03b36dd04dddaf18a4dcf. Stop the container before attempting removal or force remove
[root@jkc docker]#
但是rm 正在运行的容器时候，它会报错，需先stop，才能rm
[root@jkc docker]# docker stop admiring_mahavira
admiring_mahavira
[root@jkc docker]# docker rm admiring_mahavira
admiring_mahavira
[root@jkc docker]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
[root@jkc docker]#
删除已经停止运行的容器
如果你跟博主一样有强迫症，在使用docker ps -a发现里面有许多状态为停止的容器，那么可以用下面的命令，将其全部删除
docker container prune
[root@jkc easymock]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
9e610e19c9c0 training/webapp "/bin/bash" About a minute ago Exited (0) 16 seconds ago nervous_robinson
9b977a64610b training/webapp "/bin/bash" About a minute ago Exited (0) About a minute ago jovial_almeida
becfbf291128 training/webapp "/bin/bash" 2 minutes ago Exited (0) 2 minutes ago compassionate_germain
25743368a66d training/webapp "python app.py" 46 minutes ago Exited (137) 40 minutes ago keen_aryabhata
4d7286571786 redis:4.0.6 "docker-entrypoint.s…" 48 minutes ago Up 48 minutes 6379/tcp easymock_redis_1
4dc2b090da1b easymock/easymock:1.6.0 "/bin/bash -c 'npm s…" 48 minutes ago Up 48 minutes 0.0.0.0:7300->7300/tcp easymock_web_1
64cfd7181b19 mongo:3.4.1 "/entrypoint.sh mong…" 48 minutes ago Up 48 minutes 27017/tcp easymock_mongodb_1
713e29359fcd centos/python-36-centos7 "container-entrypoin…" 24 hours ago Exited (0) 24 hours ago priceless_allen
29980b073576 mysql:5.7 "docker-entrypoint.s…" 8 weeks ago Exited (0) 26 hours ago jkcmysql
[root@jkc easymock]# docker container prune
WARNING! This will remove all stopped containers.
Are you sure you want to continue? [y/N] y
Deleted Containers:
9e610e19c9c0389b23b3d4e1bc35023483d8e88ec4733b6f0e639596f02cd246
9b977a64610bf22f051d4bc14c08c430b3508a630cd5d3f69cb228fe368b80a0
becfbf29112833f627e7d1751ef08184ffa5a7f51f38a810281f110813935588
25743368a66d395c2a1204d798ac0e53297ad1d25c13aa5ce0ff409daf62d2bd
713e29359fcd4b2f089df0246b17b24ae0f20a315c81ccbe285e207ff920f8d2
29980b0735760a3c0a878c500b85e91f1d4e804c13d87073e07ace27bdcda7ce
Total reclaimed space: 85B
[root@jkc easymock]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4d7286571786 redis:4.0.6 "docker-entrypoint.s…" 51 minutes ago Up 51 minutes 6379/tcp easymock_redis_1
4dc2b090da1b easymock/easymock:1.6.0 "/bin/bash -c 'npm s…" 51 minutes ago Up 51 minutes 0.0.0.0:7300->7300/tcp easymock_web_1
64cfd7181b19 mongo:3.4.1 "/entrypoint.sh mong…" 51 minutes ago Up 51 minutes 27017/tcp easymock_mongodb_1
[root@jkc easymock]#
上面留下的都是正在运行的容器状态为up
