部署 Nagios 监控服务器

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2023-12-01

My roommate lost his pet elephant. It’s in the apartment somewhere. — Steven Wright

我们无法持续关注所有的一切。问题是：你怎么知道一台服务器何时会出现故障呢？错误的答案是，“我的客户打电话给我，告诉我服务器宕机了。” 但是，你会惊奇地发现，许多组织的系统没有任何的自动监控。自动监控的设置非常简单。目前有许多优秀的免费开源的自动监测工具可用，包括 Nagios、Icinga、Zabbix 和 Zenoss。 Nagios 是其中历史最久最复杂的一个，尽管它有一个难以配置的名声（基本上是实至名归的）。

本处方将向你展示如何使用 Puppet 创建一个基于 Nagios 的监控服务器以及如何让 Puppet 配置由 Nagios 监控的每台机器。

准备工作

你将需要我们已经在第 7 章的管理 Apache 服务一节中创建的 Apache 模块。

操作步骤

创建一个 nagios 模块：

# mkdir /etc/puppet/modules/nagios
# mkdir /etc/puppet/modules/nagios/files
# mkdir /etc/puppet/modules/nagios/manifests

使用如下内容创建 /etc/puppet/modules/nagios/manifests/server.pp 文件：

class nagios::server {
  include apache

  package { [ "nagios3",
        "nagios-images",
        "nagios-nrpe-plugin" ]:
    ensure => installed,
  }

  service { "nagios3":
    ensure => running,
    enable => true,
    require => Package["nagios3"],
  }

  exec { "nagios-config-check":
    command => "/usr/sbin/nagios3 -v /etc/nagios3/nagios.
     cfg && /usr/sbin/service nagios3 restart",
    refreshonly => true,
  }

  file { "/etc/apache2/sites-available/nagios.conf":
    source  => "puppet:///modules/nagios/nagios.conf",
    notify  => Service["apache2"],
    require => Package["apache2-mpm-prefork"],
  }

  file { "/etc/apache2/sites-enabled/nagios.conf":
    ensure  => symlink,
    target  => "/etc/apache2/sites-available/nagios.conf",
    require => Package["apache2-mpm-prefork"],
  }

  file { [ "/etc/nagios3/generic-service_nagios2.cfg",
       "/etc/nagios3/services_nagios2.cfg",
       "/etc/nagios3/hostgroups_nagios2.cfg",
       "/etc/nagios3/extinfo_nagios2.cfg",
       "/etc/nagios3/localhost_nagios2.cfg",
       "/etc/nagios3/contacts_nagios2.cfg",
       "/etc/nagios3/conf.d"
       ]:
    ensure => absent,
    force  => true,
  }

  define nagios-config() {
    file { "/etc/nagios3/${name}":
      source  => "puppet:///modules/nagios/${name}",
      require => Package["nagios3"],
      notify => Exec["nagios-config-check"],
    }
  }

  nagios-config { [ "htpasswd.nagios",
            "nagios.cfg",
            "cgi.cfg",
            "hostgroups.cfg",
            "hosts.cfg",
            "host_templates.cfg",
            "service_templates.cfg",
            "services.cfg",
            "timeperiods.cfg",
            "contacts.cfg",
            "commands.cfg" ]: }

  file { "/var/lib/nagios3":
    # see http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=478889
    mode  => 751,
    require => Package["nagios3"],
    notify  => Service["nagios3"],
  }

  file { "/var/lib/nagios3/rw":
    # see http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=478889
    mode  => 2710,
    require => Package["nagios3"],
    notify  => Service["nagios3"],
  }
}

使用如下内容创建 /etc/puppet/modules/nagios/files/nagios.cfg 文件：

# Config files to read
cfg_file=/etc/nagios3/commands.cfg
cfg_file=/etc/nagios3/service_templates.cfg
cfg_file=/etc/nagios3/host_templates.cfg
cfg_file=/etc/nagios3/timeperiods.cfg
cfg_file=/etc/nagios3/contacts.cfg
cfg_file=/etc/nagios3/hostgroups.cfg
cfg_file=/etc/nagios3/hosts.cfg
cfg_file=/etc/nagios3/services.cfg

# Nagios settings
log_file=/var/log/nagios3/nagios.log
illegal_macro_output_chars=`~$&|'"<>
check_result_path=/var/lib/nagios3/spool/checkresults
nagios_user=nagios
nagios_group=nagios
command_file=/var/lib/nagios3/rw/nagios.cmd
lock_file=/var/run/nagios3/nagios3.pid
p1_file=/usr/lib/nagios3/p1.pl
check_external_commands=1
resource_file=/etc/nagios3/resource.cfg

使用如下内容创建 /etc/puppet/modules/nagios/files/service_templates.cfg 文件：

define service{
  name             generic_service
   ; The 'name' of this service template
  active_checks_enabled    1
   ; Active service checks are enabled
  passive_checks_enabled     1
   ; Passive service checks are enabled/accepted
  parallelize_check      1
   ; Active service checks should be parallelized
   ; (disabling this can lead to major performance problems)
  obsess_over_service      1
   ; We should obsess over this service (if necessary)
  check_freshness        0
   ; Default is to NOT check service 'freshness'
  notifications_enabled    1
   ; Service notifications are enabled
  event_handler_enabled    1
   ; Service event handler is enabled
  flap_detection_enabled     1
   ; Flap detection is enabled
  failure_prediction_enabled   1
   ; Failure prediction is enabled
  process_perf_data      1
   ; Process performance data
  retain_status_information  1
   ; Retain status information across program restarts
  retain_nonstatus_information 1
   ; Retain non-status information across program restarts
  notification_interval    0
   ; Only send notifications on status change by default.
  is_volatile          0
  check_period         24x7
  normal_check_interval    5
  retry_check_interval     2
  max_check_attempts       3
  notification_period      24x7
  notification_options     c,r
  contact_groups         sysadmin
  register           0
   ; DONT REGISTER THIS DEFINITION
   ;   - ITS NOT A REAL SERVICE, JUST A TEMPLATE!
}

# Defaults
define service {
  name             every_5_mins
  normal_check_interval    5
  use              generic_service
  register           0
}

define service {
  name             every_hour
  normal_check_interval    60
  use              generic_service
  register           0
}

define service {
  name             every_day
  normal_check_interval    1440
  use              generic_service
  register           0
}

使用如下内容创建 /etc/puppet/modules/nagios/files/services.cfg 文件：

define service {
  hostgroup_name         all
  service_description      Disk
  check_command        check_nrpe!check_all_disks!20%!10%
  use              every_day
}

define service {
  hostgroup_name         all
  service_description      Load
  check_command        check_nrpe!check_load!10,10,10!15,15,15
  use              every_hour
}

使用如下内容创建 /etc/puppet/modules/nagios/files/cgi.cfg 文件：

main_config_file=/etc/nagios3/nagios.cfg
physical_html_path=/usr/share/nagios3/htdocs
url_html_path=/nagios3
show_context_help=1
use_pending_states=1
nagios_check_command=/usr/lib/nagios/plugins/check_nagios
 /var/cache/nagios3/status.dat 5 '/usr/sbin/nagios3'
use_authentication=1
use_ssl_authentication=0
authorized_for_system_information=nagios
authorized_for_configuration_information=nagios
authorized_for_system_commands=nagios
authorized_for_all_services=nagios
authorized_for_all_hosts=nagios
authorized_for_all_service_commands=nagios
authorized_for_all_host_commands=nagios
default_statusmap_layout=5
default_statuswrl_layout=4
ping_syntax=/bin/ping -n -U -c 5 $HOSTADDRESS$
refresh_rate=90
escape_html_tags=1
action_url_target=_blank
notes_url_target=_blank
lock_author_names=1

使用如下内容创建 /etc/puppet/modules/nagios/files/host_templates.cfg 文件：

define host{
  name              generic_host
  check_command         check-host-alive
  max_check_attempts      3
  checks_enabled        1
  failure_prediction_enabled  1
  retain_status_information   1
  retain_nonstatus_information  1
  notification_interval     0
  notification_options      d,u,r
  check_interval        300
  contact_groups        sysadmin
  register            0
}

使用如下内容创建 /etc/puppet/modules/nagios/files/contacts.cfg 文件（使用你自己的 e-mail 地址，或者至少是一个不介意从你的监控服务获得大量邮件的人的 e-mail 地址）：

define contact {
  contact_name          helen
  alias Helen           Highwater
  service_notification_period   24x7
  host_notification_period    24x7
  service_notification_options  w,u,c,r
  host_notification_options     d,r
  service_notification_commands   notify-service-by-email
  host_notification_commands    notify-host-by-email
  email               helen@example.com
}

define contactgroup {
  contactgroup_name         sysadmin
  alias               Sysadmins
  members             helen
}

使用如下内容创建 /etc/puppet/modules/nagios/files/hostgroups.cfg 文件：

define hostgroup {
  hostgroup_name           all
  alias              All Servers
  members              *
}

使用如下内容创建 /etc/puppet/modules/nagios/files/timeperiods.cfg 文件：

define timeperiod {
  timeperiod_name    24x7
  alias        24 Hours A Day, 7 Days A Week
  sunday         00:00-24:00
  monday         00:00-24:00
  tuesday        00:00-24:00
  wednesday      00:00-24:00
  thursday       00:00-24:00
  friday         00:00-24:00
  saturday       00:00-24:00
}

使用如下内容创建 /etc/puppet/modules/nagios/files/hosts.cfg 文件（使用你自己的服务器信息替换相应的配置值）：
```
define host {
  host_name       cookbook
  address       cookbook.bitfieldconsulting.com
  use         generic_host
}
```

使用如下内容创建 /etc/puppet/modules/nagios/files/commands.cfg 文件：

define command {
  command_name   check_nrpe
  command_line   $USER1$/check_nrpe -H $HOSTADDRESS$ -c $ARG1$
   -a $ARG2$ $ARG3$ $ARG4$ $ARG5$
}

define command{
  command_name  check-host-alive
  command_line  $USER1$/check_ping -H '$HOSTADDRESS$' -w
   5000,100% -c 5000,100% -p 1
}

define command{
  command_name  check_all_disks
  command_line  /usr/lib/nagios/plugins/check_disk -w '$ARG1$'
   -c '$ARG2$' -e
}

define command{
  command_name   notify-host-by-email
  command_line   /usr/bin/printf "%b" "***** Nagios *****\n\
   nNotification Type: $NOTIFICATIONTYPE$\nHost: $HOSTNAME$\
   nState: $HOSTSTATE$\nAddress: $HOSTADDRESS$\nInfo:
   $HOSTOUTPUT$\n\nDate/Time: $LONGDATETIME$\n" | /usr/bin/mail
   -s "** $NOTIFICATIONTYPE$ Host Alert: $HOSTNAME$ is
   $HOSTSTATE$ **" $CONTACTEMAIL$
}

define command{
  command_name  notify-service-by-email
  command_line  /usr/bin/printf "%b" "***** Nagios
   *****\n\nNotification Type: $NOTIFICATIONTYPE$\n\nService:
   $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\
   nState: $SERVICESTATE$\n\nDate/Time: $LONGDATETIME$\n\
   nAdditional Info:\n\n$SERVICEOUTPUT$" | /usr/bin/mail -s "**
   $NOTIFICATIONTYPE$ Service Alert: $HOSTALIAS$/$SERVICEDESC$ is
   $SERVICESTATE$ **" $CONTACTEMAIL$
}

使用如下内容创建 /etc/puppet/modules/nagios/files/nagios.conf 文件（用你自己的服务器替换 ServerName 的配置值）：

ScriptAlias /cgi-bin/nagios3 /usr/lib/cgi-bin/nagios3
ScriptAlias /nagios3/cgi-bin /usr/lib/cgi-bin/nagios3

Alias /nagios3/stylesheets /etc/nagios3/stylesheets
Alias /nagios3 /usr/share/nagios3/htdocs
Alias / /usr/share/nagios3/htdocs/

<DirectoryMatch (/usr/share/nagios3/htdocs|/usr/lib/cgi-bin/
nagios3|/etc/nagios3/stylesheets)>

  Options FollowSymLinks

  DirectoryIndex index.html

  AllowOverride AuthConfig

  Order Allow,Deny
  Allow From All

  AuthName "Nagios Access"
  AuthType Basic
  AuthUserFile /etc/nagios3/htpasswd.nagios
  require valid-user
</DirectoryMatch>

<VirtualHost *:80>
  ServerName nagios.bitfieldconsulting.com
  ErrorLog /var/log/apache2/nagios-error_log
  CustomLog /var/log/apache2/nagios-access_log common
  DocumentRoot /usr/share/nagios3
</VirtualHost>

创建口令文件控制对 Nagios web 界面的访问：

# htpasswd -c /etc/puppet/modules/nagios/files/htpasswd.nagios
nagios
Password: (type password)

如果你的系统中还没有 htpasswd 程序，运行如下的命令：
```
# apt-get install apache2-utils
```
在前面的代码中指定的 ServerName 为你创建一个 /etc/hosts 条目或 DNS 记录，本例中的主机名是：
```
nagios.bitfieldconsulting.com
```
在你的 Nagios 服务器的节点中定义中包含如下代码：
```
include nagios::server
```

使用如下内容创建 /etc/puppet/modules/nagios/files/nrpe.cfg 文件（使用你自己的监控服务器的主机名或 IP 地址替换 allowed_hosts 设置值）：

log_facility=daemon
pid_file=/var/run/nagios/nrpe.pid
server_port=5666
nrpe_user=nagios
nrpe_group=nagios
allowed_hosts=cookbook.bitfieldconsulting.com
dont_blame_nrpe=1
debug=0
command_timeout=60
connection_timeout=300
command[check_load]=/usr/lib/nagios/plugins/check_load -w $ARG1$
 -c $ARG2$
command[check_all_disks]=/usr/lib/nagios/plugins/check_disk -w
 $ARG1$ -c $ARG2$ -e -A -i '.gvfs'

使用如下内容创建 /etc/puppet/modules/nagios/manifests/target.pp 文件：

class nagios::target {
  package { [ "nagios-nrpe-server",
        "nagios-plugins",
        "nagios-plugins-basic",
        "nagios-plugins-standard",
        "nagios-plugins-extra" ]:
    ensure => installed,
  }

  service { "nagios-nrpe-server":
    enable  => true,
    ensure  => running,
    pattern => "/usr/sbin/nrpe",
    require => Package["nagios-nrpe-server"],
  }

  file { "/etc/nagios/nrpe.cfg":
    source  => "puppet:///modules/nagios/nrpe.cfg",
    require => Package["nagios-nrpe-server"],
    notify  => Service["nagios-nrpe-server"],
  }
}

在你要监控的所有节点（也应该包括 Nagios 服务器自己）上包含这个类：
```
include nagios::target
```
在 Nagios 服务器上运行如下 Puppet 命令：
```
# puppet agent --test
```
使用浏览器打开 Nagios 的 web 界面（使用用户名 nagios 和你在前面的代码中设置的口令登录）检查你看到的 Nagios 欢迎界面，如图所示：
点击 Host detail 菜单，在界面中你应该看到目标节点的列表。
点击节点的名字，之后从 Host commands 菜单中选择 "Schedule a check of all services on this host"。
在 "Force check" 复选框上打勾将其选中并单击 "Commit"。这会花几秒钟运行 Nagios 的检查。点击 "Service detail" 菜单，在界面中你应该看到显示为绿色的服务列表，如图所示：

工作原理

尽管这个处方相当的长，但是 Puppet 的配置清单本身却很简单；这里没有我们在其他处方中还没使用过的配置技巧。

本质上，我们所做的就是安装 Nagios 包，配置服务于它的 Apache 虚拟主机，为 Nagios 部署一系列的配置文件，这些配置文件用于告诉 Nagios 要检查哪些主机、检查哪些服务以及其他一些杂七杂八的配置。

在客户端，由 Nagios 监控的每个节点上都需要安装 nagios-nrpe-server 包（NRPE 是使 Nagios 能在远程服务器上安全地执行命令的协议）以及告诉 NRPE 服务允许执行哪些命令的配置文件。

你应该知道，nrpe.cfg 文件中的 dont_blame_nrpe 设置是一个潜在的安全漏洞，因为它允许在远程主机上使用用户提供的参数去执行命令。这是一个非常有用的功能，因为这意味着你可以在无需重新配置每一个监控机的情况下，就可以改变警报阈值或其他参数。然而，如果你不需要这个功能，禁用 dont_blame_nrpe 设置会更安全。

部署 Nagios 监控服务器

准备工作

操作步骤

工作原理

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