# CentOS 升级安装Python2.7.X

#### 博客作者：联系请[点击](https://hezhiqiang.gitbook.io/about-the-author/lian-xi-zuo-zhe)，搬运不易，希望请作者喝咖啡，可以点击联系[博客作者](https://hezhiqiang.gitbook.io/about-the-author/lian-xi-zuo-zhe)

## **第一步：查看Centos版本及python版本**

* **Centos版本**

```bash
[root@k8s-admin-lb ~]# cat /etc/centos-release
CentOS Linux release 7.7.1908 (Core)
```

* **Python版本**

```bash
[root@k8s-admin-lb ~]# python -V
Python 2.7.5
[root@k8s-admin-lb ~]# which python
/usr/bin/python
[root@k8s-admin-lb ~]# ll -l /usr/bin/python*
lrwxrwxrwx. 1 root root    7 Oct  8 17:14 /usr/bin/python -> python2
lrwxrwxrwx. 1 root root    9 Oct  8 17:14 /usr/bin/python2 -> python2.7
-rwxr-xr-x. 1 root root 7216 Aug  7 08:52 /usr/bin/python2.7
-rwxr-xr-x  1 root root 1835 Aug  7 08:51 /usr/bin/python2.7-config
lrwxrwxrwx  1 root root   16 Oct  8 17:20 /usr/bin/python2-config -> python2.7-config
lrwxrwxrwx  1 root root   14 Oct  8 17:20 /usr/bin/python-config -> python2-config
```

## **第二步：从官网下载python对应版本的包(以2.7.9版本为例)**

```bash
[root@k8s-admin-lb ~]# wget https://www.python.org/ftp/python/2.7.9/Python-2.7.9rc1.tgz
--2019-12-31 10:58:17--  https://www.python.org/ftp/python/2.7.9/Python-2.7.9rc1.tgz
Resolving www.python.org (www.python.org)... 151.101.108.223, 2a04:4e42:36::223
Connecting to www.python.org (www.python.org)|151.101.108.223|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 16646401 (16M) [application/octet-stream]
Saving to: ‘Python-2.7.9rc1.tgz’

100%[========================================================================================================================================================================>] 16,646,401   132KB/s   in 1m 55s

2019-12-31 11:00:12 (142 KB/s) - ‘Python-2.7.9rc1.tgz’ saved [16646401/16646401]
```

## **第三步：解压、配置、编译、安装python2.7.9**

* **安装gcc(在编译时会依赖)**

```bash
[root@k8s-admin-lb ~]# yum install -y gcc* openssl openssl-devel ncurses-devel.x86_64  bzip2-devel sqlite-devel python-devel zlib
```

* **配置、编译、安装**

```bash
[root@k8s-admin-lb ~]# tar -zvxf Python-2.7.9rc1.tgz -C /usr/local/
[root@k8s-admin-lb ~]# cd /usr/local/Python-2.7.9rc1/
[root@k8s-admin-lb Python-2.7.9rc1]# ./configure --prefix=/usr/local  && make
[root@k8s-admin-lb Python-2.7.9rc1]# make altinstall     # 不要使用make install，否则会覆盖系统自带python
```

## **第四步：安装后环境检查**

* **python安装后的版本**

```bash
[root@k8s-admin-lb ~]# python -V       # 发现版本还是原版本
Python 2.7.5
```

* **安装前后的python对比**

```bash
[root@k8s-admin-lb ~]# ll -l /usr/bin/python*         # 系统自带的
lrwxrwxrwx. 1 root root    7 Oct  8 17:14 /usr/bin/python -> python2
lrwxrwxrwx. 1 root root    9 Oct  8 17:14 /usr/bin/python2 -> python2.7
-rwxr-xr-x. 1 root root 7216 Aug  7 08:52 /usr/bin/python2.7
-rwxr-xr-x  1 root root 1835 Aug  7 08:51 /usr/bin/python2.7-config
lrwxrwxrwx  1 root root   16 Oct  8 17:20 /usr/bin/python2-config -> python2.7-config
lrwxrwxrwx  1 root root   14 Oct  8 17:20 /usr/bin/python-config -> python2-config
[root@k8s-admin-lb ~]# ll -l /usr/local/bin/python*   # 手工安装的
-rwxr-xr-x 1 root root 8205896 Dec 31 11:18 /usr/local/bin/python2.7
-rwxr-xr-x 1 root root    1687 Dec 31 11:18 /usr/local/bin/python2.7-config
```

* **备份旧版本，连接新版本**

```bash
[root@k8s-admin-lb ~]# mv /usr/bin/python /usr/bin/python2.7.5
[root@k8s-admin-lb ~]# ll -l /usr/bin/python*
lrwxrwxrwx. 1 root root    9 Oct  8 17:14 /usr/bin/python2 -> python2.7
-rwxr-xr-x. 1 root root 7216 Aug  7 08:52 /usr/bin/python2.7
lrwxrwxrwx. 1 root root    7 Oct  8 17:14 /usr/bin/python2.7.5 -> python2
-rwxr-xr-x  1 root root 1835 Aug  7 08:51 /usr/bin/python2.7-config
lrwxrwxrwx  1 root root   16 Oct  8 17:20 /usr/bin/python2-config -> python2.7-config
lrwxrwxrwx  1 root root   14 Oct  8 17:20 /usr/bin/python-config -> python2-config
[root@k8s-admin-lb ~]# ln -s /usr/local/bin/python2.7 /usr/bin/python
[root@k8s-admin-lb ~]# ll -l /usr/bin/python*
lrwxrwxrwx  1 root root   24 Dec 31 11:32 /usr/bin/python -> /usr/local/bin/python2.7
lrwxrwxrwx. 1 root root    9 Oct  8 17:14 /usr/bin/python2 -> python2.7
-rwxr-xr-x. 1 root root 7216 Aug  7 08:52 /usr/bin/python2.7
lrwxrwxrwx. 1 root root    7 Oct  8 17:14 /usr/bin/python2.7.5 -> python2
-rwxr-xr-x  1 root root 1835 Aug  7 08:51 /usr/bin/python2.7-config
lrwxrwxrwx  1 root root   16 Oct  8 17:20 /usr/bin/python2-config -> python2.7-config
lrwxrwxrwx  1 root root   14 Oct  8 17:20 /usr/bin/python-config -> python2-config
```

* **再次检查python版本**

```bash
[root@k8s-admin-lb ~]# python -V
Python 2.7.9rc1
```

* **若想访问老版本python(如2.7.5版本)**

```bash
[root@k8s-admin-lb ~]# python2.7.5 -V
Python 2.7.5
```

* **其他python访问，比如python2、python2.7**

```bash
[root@k8s-admin-lb ~]# python2 -V
Python 2.7.5
[root@k8s-admin-lb ~]# python2.7 -V
Python 2.7.9rc1
```

## 第五步：设置yum**(系统预装的yum引用的老版本python)**

```bash
[root@k8s-admin-lb ~]# yum -y install epel-release      #yum这个时候是报错的
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:

   No module named yum

Please install a package which provides this module, or
verify that the module is installed correctly.

It's possible that the above module doesn't match the
current version of Python, which is:
2.7.9rc1 (default, Dec 31 2019, 11:15:01)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)]

If you cannot solve this problem yourself, please go to
the yum faq at:
  http://yum.baseurl.org/wiki/Faq
```

* **更改设置**

```bash
[root@k8s-admin-lb ~]# which yum
/usr/bin/yum
[root@k8s-admin-lb ~]# vim /usr/bin/yum
首行的#!/usr/bin/python 改为 #!/usr/bin/python2.7
[root@k8s-admin-lb ~]# vim /usr/libexec/urlgrabber-ext-down
首行的#!/usr/bin/python 改为 #!/usr/bin/python2.7
```

* **测试yum是否可用**

```bash
[root@k8s-admin-lb ~]# yum -y install epel-release
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Resolving Dependencies
--> Running transaction check
---> Package epel-release.noarch 0:7-12 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

=================================================================================================================================================================================================================
 Package                                                 Arch                                              Version                                         Repository                                       Size
=================================================================================================================================================================================================================
Installing:
 epel-release                                            noarch                                            7-12                                            epel                                             15 k

Transaction Summary
=================================================================================================================================================================================================================
Install  1 Package

Total download size: 15 k
Installed size: 24 k
Downloading packages:
epel-release-7-12.noarch.rpm                                                                                                                                                              |  15 kB  00:00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : epel-release-7-12.noarch                                                                                                                                                                      1/1
warning: /etc/yum.repos.d/epel.repo created as /etc/yum.repos.d/epel.repo.rpmnew
  Verifying  : epel-release-7-12.noarch                                                                                                                                                                      1/1

Installed:
  epel-release.noarch 0:7-12

Complete!
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://hezhiqiang.gitbook.io/about-the-author/yun-wei-huan-jing-da-jian/centos7.7-sheng-ji-an-zhuang-python2.7.9.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.