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环境:
OS: Linux
release: Ubuntu 18.04.1
version: generic 5.0.0-36

0x00 shadowsocks

由于众所周知的原因，我们无法正常访问互联网，对一些职业比如程序员的工作造成了极大的障碍，所以学会科学上网是必须的。具体的方法比较多, 个人一直使用shadowsocks(以下简称ss). ss上网原理如下图所示:

ss

可见, ss分为服务器和客户端两部分，为了能科学上网，需要先在远端部署代理服务器，然后在本地启动代理客户端，由客户端代理访问外网的流量。

0x01 服务器

个人在vultr上搭建了ss服务器.

0x02 客户端

window和MacOS版本都比较好用，ubuntu下一直没找到比较好用的客户端。之前一直用shadowsocks-qt5,下载之后双击即可启动。但是无法(没找到方法)开机启动，每次系统重启都要手动开客户端，比较麻烦。今天在这个网站上看到ubuntu下可以直接用apt安装shadowsocks-libev,决定试一下。

安装shadowsocks-libev

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$ sudo apt install shadowsocks-libev

Note:
目前不太清楚shadowsocks与shadowsocks-libev的区别，有空再看吧。

systemd

systemd的设计目标是，为系统的启动和管理提供一套完整的解决方案。主要用来管理守护进程.
关于systemd,可以看一下耗子叔写的这篇LINUX PID 1 和 SYSTEMD以及阮一峰老师写的Systemd 入门教程.如有兴趣，可以继续深入探索。

使用apt安装之后，shadowsock-libev被systemd自动接管.

参数配置

systemd管理下的shadowsocks-libev，配置文件路径为

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/etc/shadowsocks-libev/config.json

编辑config.json文件，写入自己的配置，比如:

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{
    "server":"服务器域名或ip",
    "server_port":8311, // ss服务器端口，数值类型
    "local_port":1080,  // ss客户端端口，数值类型
    "password":"密码",  // 密码
    "timeout":60,
    "method":"aes-256-cfb"  // 加密方式
}

启动客户端

apt安装shadowsocks-libev之后，自动配置了如下的service:

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shadowsocks-libev-local@.service   
shadowsocks-libev-server@.service
shadowsocks-libev-tunnel@.service
shadowsocks-libev-redir@.service
shadowsocks-libev.service

看名字，觉得shadowsocks-libev-local@.service应该是客户端服务，执行命令:

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systemctl start shadowsocks-libev-local@.service

没想到报了以下错误:

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Failed to get properties: Unit name shadowsocks-libev-local@.service is neither a valid invocation ID nor unit name.

2019-12-03 update

打开/lib/systemd/system/shadowsocks-libev-local@.service, 加入user, group，修改ExecStart为:

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ExecStart=/usr/bin/ss-local -c /etc/shadowsocks-libev/config.json

修改后的/lib/systemd/system/shadowsocks-libev-local@.service内容如下：

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#  This file is part of shadowsocks-libev.
#
#  Shadowsocks-libev is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 3 of the License, or
#  (at your option) any later version.
#
#  This is a template unit file. Users may copy and rename the file into
#  config directories to make new service instances. See systemd.unit(5)
#  for details.

[Unit]
Description=Shadowsocks-Libev Custom Client Service for %I
Documentation=man:ss-local(1)
After=network.target

[Service]
Type=simple
# CapabilityBoundingSet=CAP_NET_BIND_SERVICE
User=nobody
Group=nogroup
LimitNOFILE=32768
ExecStart=/usr/bin/ss-local -c /etc/shadowsocks-libev/config.json
# ExecStart=/usr/bin/ss-local -c $CONFFILE $DAEMON_ARGS


[Install]
WantedBy=multi-user.target

重载service配置:

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systemctl daemon-reload

启动ss-local:

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systemctl start shadowsocks-libev-local@service

查看shadowsocks-libev-local状态:

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systemctl status shadowsocks-libev-local@service

结果如下：

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● shadowsocks-libev-local@service.service - Shadowsocks-Libev Custom Client Service for service
   Loaded: loaded (/lib/systemd/system/shadowsocks-libev-local@.service; disabled; vendor preset: enabled)
   Active: active (running) since Tue 2019-12-03 14:27:34 CST; 25min ago
     Docs: man:ss-local(1)
 Main PID: 13981 (ss-local)
    Tasks: 1 (limit: 4915)
   CGroup: /system.slice/system-shadowsocks\x2dlibev\x2dlocal.slice/shadowsocks-libev-local@service.service
           └─13981 /usr/bin/ss-local -c /etc/shadowsocks-libev/config.json

12月 03 14:27:34 lfn-Lenovo systemd[1]: Started Shadowsocks-Libev Custom Client Service for service

颜色为绿，Active为active(running)，说明应该没问题了。

登录谷歌验证。

开机启动

执行下面命令，开机自动激活单元(服务).

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systemctl enable shadowsocks-libev-local@service

0x03 小结

本文记录了用systemd管理shadowsocks-libev客户端时遇到的一些问题和解决办法。
其实很简答，修改
/lib/systemd/system/shadowsocks-libev-local@.service 中部分内容即可。

通过本次折腾：

  • 了解了systemd下systemdctl和journalctl部分命令的用法；

  • 验证了/etc/init.d/下的文件与systemd系统无关。

0x04 参考文章

全文完。

=====以下内容无效==========

不太知道怎么回事，试一下shadowsocks-libev.service, 执行命令：

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systemctl start shadowsocks-libev.service

发现可以启动成功，不过被启动的却是服务端程序. 执行获取状态命令:

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systemctl status shadowsocks-libev.service
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● shadowsocks-libev.service - Shadowsocks-libev Default Server Service
   Loaded: loaded (/lib/systemd/system/shadowsocks-libev.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2019-12-02 16:03:52 CST; 4h 46min ago
     Docs: man:shadowsocks-libev(8)
 Main PID: 31885 (ss-server)
    Tasks: 1 (limit: 4915)
   CGroup: /system.slice/shadowsocks-libev.service
           └─31885 /usr/bin/ss-server -c /etc/shadowsocks-libev/config.json -u

12月 02 16:03:52 lfn-Lenovo systemd[1]: Started Shadowsocks-libev Default Server Service.

根据status返回结果，我们可以知道,systemd在shadowsocks-libev.service中，启动的是/user/bin/ss-server. 那么我们将其修改成/user/bin/ss-local不就行了。

service的配置路径在哪里呢？再看一下status返回结果中的loaded一行，可以发现路径为:

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/lib/systemd/system/shadowsocks-libev.service

打开service文件：

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#  This file is part of shadowsocks-libev.
#
#  Shadowsocks-libev is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 3 of the License, or
#  (at your option) any later version.
#
#  This file is default for Debian packaging. See also
#  /etc/default/shadowsocks-libev for environment variables.

[Unit]
Description=Shadowsocks-libev Default Server Service
Documentation=man:shadowsocks-libev(8)
After=network.target

[Service]
Type=simple
EnvironmentFile=/etc/default/shadowsocks-libev
User=nobody
Group=nogroup
LimitNOFILE=32768
ExecStart=/usr/bin/ss-server -c $CONFFILE $DAEMON_ARGS

[Install]
WantedBy=multi-user.target

在[service]下，我们看到启动命令是：

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ExecStart=/usr/bin/ss-server -c $CONFFILE $DAEMON_ARGS

修改为

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ExecStart=/usr/bin/ss-local -c $CONFFILE $DAEMON_ARGS

这样应该就可以了吧？not really！

是的。

=========作废分割线================

### start-stop-daemon

经过进一步调查研究，systemd管理守护进程与/etc/init.d/shadowsocks-libev 没有直接关系，本节作废。

[service]下有一行是EnvironmentFile=/etc/default/shadowsocks-libev，打开这个文件，我们看到：

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# Defaults for shadowsocks initscript
# sourced by /etc/init.d/shadowsocks-libev
# installed at /etc/default/shadowsocks-libev by the maintainer scripts

#
# This is a POSIX shell fragment
#
# Note: `START', `GROUP' and `MAXFD' options are not recognized by systemd.
# Please change those settings in the corresponding systemd unit file.

# Enable during startup?
START=yes

# Configuration file
CONFFILE="/etc/shadowsocks-libev/config.json"

# Extra command line arguments
DAEMON_ARGS="-u"

# User and group to run the server as
USER=nobody
GROUP=nogroup

# Number of maximum file descriptors
MAXFD=32768

注意，这里注释中有一句：

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# sourced by /etc/init.d/shadowsocks-libev

打开/etc/init.d/shadowsocks-libev, 其中有一行是：

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DAEMON=/usr/bin/ss-server    # Introduce the server's location here

可见这个脚本中可执行程序还是配置为了/usr/bin/ss-server, 将其改为ss-local:

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DAEMON=/usr/bin/ss-local    # Introduce the server's location here

仔细阅读/etc/init.d/shadowsocks-libev，发现实际上启动shadowsocks-libev守护进程的是case中的start)中的do_start函数:

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case "$1" in
    start)
        [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC " "$NAME"
        do_start
        case "$?" in
            0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;

do_start函数如下:

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do_start()
{
    # Modify the file descriptor limit
    ulimit -n ${MAXFD}

    # Take care of pidfile permissions
    mkdir /var/run/$NAME 2>/dev/null || true
    chown "$USER:$GROUP" /var/run/$NAME

    # Return
    #   0 if daemon has been started
    #   1 if daemon was already running
    #   2 if daemon could not be started
    start-stop-daemon --start --quiet --pidfile $PIDFILE --chuid $USER:$GROUP --exec $DAEMON --test > /dev/null \
        || return 1
    start-stop-daemon --start --quiet --pidfile $PIDFILE --chuid $USER:$GROUP --exec $DAEMON -- \
        -c "$CONFFILE" -u -f $PIDFILE $DAEMON_ARGS \
        || return 2
}

可得出来，do_start中实际干活的是start-stop-daemon命令。

start-stop-daemon 为系统自带函数，可以将普通程序以守护进程 方式运行.

看了下自己的/etc/init.d目录，发现redis, docker, mysql等知名软件都是用start-stop-daemon命令启动管理的。

========作废分割线=============

启动shadowsocks-libev.service

到这里，将shadowsocks-libev中可执行目标程序的/usr/bin/ss-server换成/usr/bin/ss-local的目标就完成了。执行start：

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systemctl start shadowsocks-libev

查看服务状态

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systemctl status shadowsocks-libev
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● shadowsocks-libev.service - Shadowsocks-libev Default local  Service
   Loaded: loaded (/lib/systemd/system/shadowsocks-libev.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2019-12-02 16:03:52 CST; 5h 6min ago
     Docs: man:shadowsocks-libev(8)
 Main PID: 31885 (ss-local)
    Tasks: 1 (limit: 4915)
   CGroup: /system.slice/shadowsocks-libev.service
           └─31885 /usr/bin/ss-local -c /etc/shadowsocks-libev/config.json -u

12月 02 16:03:52 lfn-Lenovo systemd[1]: Started Shadowsocks-libev Default Server Service.

Active为绿色，值为active (running)
访问谷歌测试，一切ok.

0x03 小结

本文记录了用systemd管理shadowsocks-libev客户端时遇到的一些问题和解决办法。
总的来说，修改
/lib/systemd/system/shadowsocks-libev.service
文件中下处内容即可直接用shadowsocks-libev.service启动ss-local:

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ExecStart=/usr/bin/ss-server -c $CONFFILE $DAEMON_ARGS

可能在ubuntu下运行客户端存在更简单直接的方法，如果您知道，请不吝告知，谢谢～～

code

完结。