由于控制进程退出错误，fail2ban.service作业失败

Question

关于在我的一台机器上启动fail2ban，我有一个基本问题。我今天刚安装了一台带有Ubuntu16.04的机器，我正在遵循fail2ban上来自这、这、这和这的各种指令。(我跟踪了几个交叉引用，并且因为官方的fail2ban常见问题 (为了公平起见，我也交叉引用)似乎过时了，因为它指的是fail2ban 0.8 (并且没有Ubuntu特定的说明)，而我有0.9.3：

$ fail2ban-client --version
Fail2Ban v0.9.3

Copyright (c) 2004-2008 Cyril Jaquier, 2008- Fail2Ban Contributors
Copyright of modifications held by their respective authors.
Licensed under the GNU General Public License v2 (GPL).

Written by Cyril Jaquier .
Many contributions by Yaroslav O. Halchenko .

我安装了fail2ban

sudo apt-get install fail2ban

还有sendmail，这大概允许电子邮件的发生。

$ sudo apt-get install sendmail
Reading package lists... Done
Building dependency tree       
Reading state information... Done
sendmail is already the newest version (8.15.2-3).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

按照上面指南中的说明，我将/etc/fail2ban/jail.conf文件复制到/etc/fail2ban/jail.local中，注释掉了所有行，然后只更改了/etc/fail2ban/jail.local中的以下四项内容。(在下面，我粘贴vim中显示的行号，这对于检查是否有类似的监狱文件很有用。)

(1)最大重试，我改为3，所以在系统阻止用户进行ssh-ing之前，应该有3次尝试失败。

 65 # # "maxretry" is the number of failures before a host get banned.
 66 maxretry = 3

(2)和(3)：我更改了这两项，第一项用我的个人电子邮件(即[mypersonalemail])，另一项用电脑名称。我刚输入了“ComputerName”--在这里写电子邮件会更好吗？

129 destemail = [mypersonalemail]
130 
131 # # Sender email address used solely for some actions
132 sender = ComputerName

(4)最后，我将动作改为更具表现力的动作，因此它给出了一个电子邮件通知。

201 # # Choose default action.  To change, just override value of 'action' with the
202 # # interpolation to the chosen action shortcut (e.g.  action_mw, action_mwl, etc) in jail.local
203 # # globally (section [DEFAULT]) or per specific section
204 action = %(action_mwl)s

这样，下一步似乎是以某种方式启动服务。我不想在这里获得漂亮的regexs，或者有定制的监狱，或者摆弄IP表。<#>At这一点，我感兴趣的是启动服务，并通过让我使用故意错误的密码反复进入机器来测试它。

不幸的是，当我试图启动服务时，我得到了错误：

$ sudo service fail2ban start
Job for fail2ban.service failed because the control process exited with error code. See "systemctl status fail2ban.service" and "journalctl -xe" for details.

具有输出(计算机名称是机器的名称)：

$ systemctl status fail2ban.service
● fail2ban.service - Fail2Ban Service
   Loaded: loaded (/lib/systemd/system/fail2ban.service; enabled; vendor preset: enabled)
   Active: failed (Result: start-limit-hit) since Fri 2018-12-07 17:03:55 PST; 29s ago
     Docs: man:fail2ban(1)
  Process: 21838 ExecStart=/usr/bin/fail2ban-client -x start (code=exited, status=255)
 Main PID: 6381 (code=killed, signal=TERM)
Dec 07 17:03:55 computer-name systemd[1]: Failed to start Fail2Ban Service.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Unit entered failed state.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Failed with result 'exit-code'.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Service hold-off time over, scheduling restart.
Dec 07 17:03:55 computer-name systemd[1]: Stopped Fail2Ban Service.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Start request repeated too quickly.
Dec 07 17:03:55 computer-name systemd[1]: Failed to start Fail2Ban Service.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Unit entered failed state.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Failed with result 'start-limit-hit'.

和

$ journalctl -xe
Dec 07 17:03:55 computer-name systemd[1]: Failed to start Fail2Ban Service.
-- Subject: Unit fail2ban.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit fail2ban.service has failed.
-- 
-- The result is failed.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Unit entered failed state.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Failed with result 'exit-code'.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Service hold-off time over, scheduling restart.
Dec 07 17:03:55 computer-name systemd[1]: Stopped Fail2Ban Service.
-- Subject: Unit fail2ban.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit fail2ban.service has finished shutting down.
Dec 07 17:03:55 computer-name systemd[1]: Starting Fail2Ban Service...
-- Subject: Unit fail2ban.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit fail2ban.service has begun starting up.
Dec 07 17:03:55 computer-name fail2ban-client[21838]: ERROR  Failed during configuration: File contains no section headers.
Dec 07 17:03:55 computer-name fail2ban-client[21838]: file: '/etc/fail2ban/jail.local', line: 66
Dec 07 17:03:55 computer-name fail2ban-client[21838]: 'maxretry = 3\n'
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Control process exited, code=exited status=255
Dec 07 17:03:55 computer-name systemd[1]: Failed to start Fail2Ban Service.
-- Subject: Unit fail2ban.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit fail2ban.service has failed.
-- 
-- The result is failed.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Unit entered failed state.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Failed with result 'exit-code'.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Service hold-off time over, scheduling restart.
Dec 07 17:03:55 computer-name systemd[1]: Stopped Fail2Ban Service.
-- Subject: Unit fail2ban.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit fail2ban.service has finished shutting down.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Start request repeated too quickly.
Dec 07 17:03:55 computer-name systemd[1]: Failed to start Fail2Ban Service.
-- Subject: Unit fail2ban.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit fail2ban.service has failed.
-- 
-- The result is failed.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Unit entered failed state.
Dec 07 17:03:55 computer-name systemd[1]: fail2ban.service: Failed with result 'start-limit-hit'.
Dec 07 17:04:32 computer-name org.gtk.vfs.Daemon[1529]: ** (process:3758): WARNING **: Couldn't create directory monitor on smb://x-gnome-

有人有什么建议吗？谢谢。

PS:有一些类似的问题：

• 这一个似乎对sendmail/postfix有问题，但是我已经安装了sendmail，应该已经足够了吗？
• 这一个也是类似的，但我关注的是apache2，而我关注的是fail2ban，并不关心apache2。

Answer 1

我也有这个问题。首先，我运行命令：

sudo fail2ban-client -vvv -x start

我发现了一个错误：

ERROR  There is no directory /var/run/fail2ban to contain the socket file /var/run/fail2ban/fail2ban.sock.

之后，我创建了缺少的目录，运行以下命令，所有操作都正常。

sudo mkdir /var/run/fail2ban