利用Nagios远程监控软件监控网页[服务器安全]

1. 问题的由来

关于一个网站来说,外部用户可以看到就是该网站的页面.网站页面可否被正常拜候,以及显示能否正常必将会成为网站整体水平最直接的外在表现.

那么,若何才能在第一时间检测到网页能否正常,并且给呼应的技术人员发出报警来及时办理问题,而不是等接到用户抱怨的电话后才在匆忙中仓促的办理问题呢?办理这个问题的关键就是要在第一时间发现问题,发现那些不能显示的网页或是显示不正常的网页,并及时发出报警.当然我们可以通过人工的办法去监测,但关于一些大型的、复杂的网站来说就不是很符合了,我们可以利用监控软件来办理这个问题.我所利用的就是Nagios软件,它供应的插件（Plugins）中有呼应的号令可以完成对网页的监控.



2. 若何通过Nagios办理此类问题

关于Nagios、NRPE以及Nagios Plugins的安装配置网站的资料很多,在我的Blog中也有呼应的文章可以参考,在这里就不再过量的阐明了.

想利用Nagios监控网页情况,Nagios插件中的一个号令不得不被说起,那就是check_http,我没可以利用它来查抄网页能否正常、可用.该号令的具体阐明和用法以下.


Usage: check_http -H <vhost> | -I <IP-address> [-u <uri>] [-p <port>]
[-w <warn time>] [-c <critical time>] [-t <timeout>] [-L]
[-a auth] [-f <ok | warn | critcal | follow>] [-e <expect>]
[-s string] [-l] [-r <regex> | -R <case-insensitive regex>] [-P string]
[-m <min_pg_size>:<max_pg_size>] [-4|-6] [-N] [-M <age>] [-A string]
[-k string] [-S] [-C <age>] [-T <content-type>]
NOTE: One or both of -H and -I must be specified

Options:
-h, --help
Print detailed help screen
-V, --version
Print version information
-H, --hostname=ADDRESS
Host name argument for servers using host headers (virtual host)
Append a port to include it in the header (eg: example.com:5000)
-I, --IP-address=ADDRESS
IP address or name (use numeric address if possible to bypass DNS lookup).
-p, --port=INTEGER
Port number (default: 80)
-4, --use-ipv4
Use IPv4 connection
-6, --use-ipv6
Use IPv6 connection
-S, --ssl
Connect via SSL. Port defaults to 443
-C, --certificate=INTEGER
Minimum number of days a certificate has to be valid. Port defaults to 443
(when this option is used the url is not checked.)

-e, --expect=STRING
String to expect in first (status) line of server response (default:
HTTP/1.)
If specified skips all other status line logic (ex: 3xx, 4xx, 5xx processing)
-s, --string=STRING
String to expect in the content
-u, --url=PATH
URL to GET or POST (default: /)
-P, --post=STRING
URL encoded http POST data
-N, --no-body
Don't wait for document body: stop reading after headers.
(Note that this still does an HTTP GET or POST, not a HEAD.)
-M, --max-age=SECONDS
Warn if document is more than SECONDS old. the number can also be of
the form "10m" for minutes, "10h" for hours, or "10d" for days.
-T, --content-type=STRING
specify Content-Type header media type when POSTing

-l, --linespan
Allow regex to span newlines (must precede -r or -R)
-r, --regex, --ereg=STRING
Search page for regex STRING
-R, --eregi=STRING
Search page for case-insensitive regex STRING
--invert-regex
Return CRITICAL if found, OK if not

-a, --authorization=AUTH_PAIR
Username:password on sites with basic authentication
-A, --useragent=STRING
String to be sent in http header as "User Agent"
-k, --header=STRING
Any other tags to be sent in http header. Use multiple times for additional headers
-L, --link
Wrap output in HTML link (obsoleted by urlize)
-f, --onredirect=<ok|warning|critical|follow>
How to handle redirected pages
-m, --pagesize=INTEGER<:INTEGER>
Minimum page size required (bytes) : Maximum page size required (bytes)
-w, --warning=DOUBLE
Response time to result in warning status (seconds)
-c, --critical=DOUBLE
Response time to result in critical status (seconds)
-t, --timeout=INTEGER
Seconds before connection times out (default: 10)
-v, --verbose
Show details for command-line debugging (Nagios may truncate output)



通过check_http的帮忙我们可以清楚的理解到该号令可认为我们做什么,以及若何去做.选项固然很多,其实常被用到的却只有几项,并且很多选项是有默许值的普通无需设置.下面就我们需求用到的几个选项做一个扼要的阐明.选 项 说 明
-H, --hostname=ADDRESS 主机名或域名
-I, --IP-address=ADDRESS server的IP地址,用于在不能DNS的情形下
-p, --port=INTEGER 端口号,默许80
-u, --url=PATH url,默许是/
-w, --warning=DOUBLE warning状况的呼应时间,单位是秒
-c, --critical=DOUBLE critical状况的呼应时间,单位是秒
-t, --timeout=INTEGER 衔接超不时间,默许10秒



举一个简单的实例,一个网站的域名是www.testhost.test,端口是默许80,需求监测它的主页/index.html,warning时间和critical时间、 timeout时间利用默许值,不设置.具体号令书写以下.