First, python is installed by default under Centos, but it is still python 2.
To better use the extension adapted to Python 3, we installed Python 3.

Installation of basic dependencies:

sudo yum install -y ncurses-libs zlib-devel mysql-devel bzip2-devel openssl-devel
sudo yum groupinstall 'Development Tools'

II. Preparations

Check the installed python:

[Air@heyue ~]$ python --version
Python 2.7.5

[Air@heyue ~]$ which python
/usr/bin/python

[Air@heyue ~]$ ls -l `which python`*
lrwxrwxrwx 1 root root    7 Jun 15 06:57 /usr/bin/python -> python2
lrwxrwxrwx 1 root root    9 Jun 15 06:57 /usr/bin/python2 -> python2.7
-rwxr-xr-x 1 root root 7216 Apr 11 03:36 /usr/bin/python2.7

Since Python 2 has been installed in the system, we usually use only Python 2 links.
The underlying usage is Python 2, which can't directly point the python link to Python 3.

So, like in the relevant references to yum, we can directly change python to python 2:

[Air@heyue ~]$  ls -l /usr/bin/yum*
-rwxr-xr-x 1 root root   802 Jun 15 07:06 /usr/bin/yum
-rwxr-xr-x 1 root root 10190 Jun 15 07:07 /usr/bin/yum-builddep
-rwxr-xr-x 1 root root  9040 Jun 15 07:07 /usr/bin/yum-config-manager
-rwxr-xr-x 1 root root  8539 Jun 15 07:07 /usr/bin/yum-debug-dump
-rwxr-xr-x 1 root root  7904 Jun 15 07:07 /usr/bin/yum-debug-restore
-rwxr-xr-x 1 root root 11115 Jun 15 07:08 /usr/bin/yumdownloader
-rwxr-xr-x 1 root root 11032 Jun 15 07:08 /usr/bin/yum-groups-manager

You can change python to python 2:

#!/usr/bin/python

For:

#!/usr/bin/python2

Download and install Python 3

stay Official website Download the source package for Python 3:

wget https://www.python.org/ftp/python/3.6.5/Python-3.6.5.tgz

I put it here in / usr/local/src:
Compile and install:

# tar -xvf Python-3.6.5.tgz
# cd Python-3.6.5/
# ./configure --prefix=/usr/local/python3.6 --enable-optimizations

Configure prefix here, such as:. / configure prefix = / usr / local / Python 3.6, is to place all files in / usr / local / Python 3.6;

After configure, Makefile is created, so make is used for installation.

make 
make test
make install

After installation, you can add / usr / local / Python 3.6 / bin to the PATH of. bashrc.

PATH=/usr/local/python3.6/bin:$PATH
export PATH

IV. Using pip

Read. bashrc again to see if Python 3 and pip3 are set correctly:

. .bashrc
python3 --version
pip3 --version

Installation:

pip3 list                                   # View installed
sudo pip3 install --upgrade pip             # Upgrade pip
sudo pip3 install virtualenv                # Install virtualenv
sudo pip3 install virtualenvwrapper         # Install virtualenvwrapper

Create a general place, such as

mkdir ~/.Envs

Then configure virtualenvwrapper in. bashrc:

export WORKON_HOME=~/.Envs
export VIRTUALENVWRAPPER_PYTHON=/usr/local/python3.6/bin/python3
source /usr/local/python3.6/bin/virtualenvwrapper.sh

Next, we use lsvirtualenv to view the virtual environment, mkvirtualenv to create the virtual environment, and rmvirtualenv to delete the virtual environment.

mkvirtualenv ss
workon ss
pip list
pip install shadowsocks

In a virtual environment called ss, SS is installed and then used:

(s s) [Air@heyue ~]$sudo ssserver-s:: 0-P port number-k password-m aes-256-cfb (encryption) -- user Nobody -- workers 2-D start

Open SS service;
View the process:

(ss) [Air@heyue ~]$  ps aux | grep ssserver
root     29207  0.0  1.1 196568 12144 ?        Ss   08:41   0:00 /home/Air/.Envs/ss/bin/python3.6 /home/Air/.Envs/ss/bin/ssserver -s ::0 -p port -k Password -m aes-256-cfb --user nobody --workers 2 -d start
nobody   29208  0.0  1.2 198968 13016 ?        S    08:41   0:02 /home/Air/.Envs/ss/bin/python3.6 /home/Air/.Envs/ss/bin/ssserver -s ::0 -p port -k Password -m aes-256-cfb --user nobody --workers 2 -d start
nobody   29209  0.0  1.2 198988 13028 ?        S    08:41   0:02 /home/Air/.Envs/ss/bin/python3.6 /home/Air/.Envs/ss/bin/ssserver -s ::0 -p port -k Password -m aes-256-cfb --user nobody --workers 2 -d start
Air      29377  0.0  0.2 112716  2392 pts/1    S+   09:44   0:00 grep --color=auto ssserver

If you want to stop, use ssserver-d stop;

Above.