我的apache2( Ubuntu 12.04) 在一段时间内（可变）出现了异常的系统资源利用率。我确信我没有那流量和 dos/ddos 几乎不在列表中，因为没有 Web 服务器重启可以对 dos/ddos 产生任何影响。
有哪些症状？
系统负载（uptime命令）显示2- 2.5- 3。在 8 核机器上，除非发生其他情况，否则通常负载不会超过0.8，通常是0.1- 0.2。
top事实证明，指挥部apache才是罪魁祸首。
为什么我要如此重视可容忍的系统负载？
看起来磁盘 I/O 也增加了（温度上升了 2-3 摄氏度），我宁愿避免这种情况，因为两个硬盘都用了好几年了。我不知道这会发生什么。
配置文件/etc/apache2/apache2.conf（删除了大量的注释）：
#
# The accept serialization lock file MUST BE STORED ON A LOCAL DISK.
#
LockFile ${APACHE_LOCK_DIR}/accept.lock
#
# PidFile: The file in which the server should record its process
# identification number when it starts.
# This needs to be set in /etc/apache2/envvars
#
PidFile ${APACHE_PID_FILE}
#
# Timeout: The number of seconds before receives and sends time out.
#
Timeout 300
#
# KeepAlive: Whether or not to allow persistent connections (more than
# one request per connection). Set to "Off" to deactivate.
#
KeepAlive On
#
# MaxKeepAliveRequests: The maximum number of requests to allow
# during a persistent connection. Set to 0 to allow an unlimited amount.
# We recommend you leave this number high, for maximum performance.
#
MaxKeepAliveRequests 100
#
# KeepAliveTimeout: Number of seconds to wait for the next request from the
# same client on the same connection.
#
KeepAliveTimeout 5
##
## Server-Pool Size Regulation (MPM specific)
##
# prefork MPM
# StartServers: number of server processes to start
# MinSpareServers: minimum number of server processes which are kept spare
# MaxSpareServers: maximum number of server processes which are kept spare
# MaxClients: maximum number of server processes allowed to start
# MaxRequestsPerChild: maximum number of requests a server process serves
<IfModule mpm_prefork_module>
StartServers 5
MinSpareServers 5
MaxSpareServers 10
MaxClients 150
MaxRequestsPerChild 0
</IfModule>
# worker MPM
# StartServers: initial number of server processes to start
# MinSpareThreads: minimum number of worker threads which are kept spare
# MaxSpareThreads: maximum number of worker threads which are kept spare
# ThreadLimit: ThreadsPerChild can be changed to this maximum value during a
# graceful restart. ThreadLimit can only be changed by stopping
# and starting Apache.
# ThreadsPerChild: constant number of worker threads in each server process
# MaxClients: maximum number of simultaneous client connections
# MaxRequestsPerChild: maximum number of requests a server process serves
<IfModule mpm_worker_module>
StartServers 2
MinSpareThreads 25
MaxSpareThreads 75
ThreadLimit 64
ThreadsPerChild 25
MaxClients 150
MaxRequestsPerChild 0
</IfModule>
# event MPM
# StartServers: initial number of server processes to start
# MinSpareThreads: minimum number of worker threads which are kept spare
# MaxSpareThreads: maximum number of worker threads which are kept spare
# ThreadsPerChild: constant number of worker threads in each server process
# MaxClients: maximum number of simultaneous client connections
# MaxRequestsPerChild: maximum number of requests a server process serves
<IfModule mpm_event_module>
StartServers 2
MinSpareThreads 25
MaxSpareThreads 75
ThreadLimit 64
ThreadsPerChild 25
MaxClients 150
MaxRequestsPerChild 0
</IfModule>
# These need to be set in /etc/apache2/envvars
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}
#
# AccessFileName: The name of the file to look for in each directory
# for additional configuration directives. See also the AllowOverride
# directive.
#
AccessFileName .htaccess
#
# The following lines prevent .htaccess and .htpasswd files from being
# viewed by Web clients.
#
<Files ~ "^\.ht">
Order allow,deny
Deny from all
Satisfy all
</Files>
#
# DefaultType is the default MIME type the server will use for a document
# if it cannot otherwise determine one, such as from filename extensions.
# If your server contains mostly text or HTML documents, "text/plain" is
# a good value. If most of your content is binary, such as applications
# or images, you may want to use "application/octet-stream" instead to
# keep browsers from trying to display binary files as though they are
# text.
#
# It is also possible to omit any default MIME type and let the
# client's browser guess an appropriate action instead. Typically the
# browser will decide based on the file's extension then. In cases
# where no good assumption can be made, letting the default MIME type
# unset is suggested instead of forcing the browser to accept
# incorrect metadata.
#
DefaultType None
#
# HostnameLookups: Log the names of clients or just their IP addresses
# e.g., www.apache.org (on) or 204.62.129.132 (off).
# The default is off because it'd be overall better for the net if people
# had to knowingly turn this feature on, since enabling it means that
# each client request will result in AT LEAST one lookup request to the
# nameserver.
#
HostnameLookups Off
# ErrorLog: The location of the error log file.
# If you do not specify an ErrorLog directive within a <VirtualHost>
# container, error messages relating to that virtual host will be
# logged here. If you *do* define an error logfile for a <VirtualHost>
# container, that host's errors will be logged there and not here.
#
ErrorLog ${APACHE_LOG_DIR}/error.log
#
# LogLevel: Control the number of messages logged to the error_log.
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
#
LogLevel warn
# Include module configuration:
Include mods-enabled/*.load
Include mods-enabled/*.conf
# Include all the user configurations:
Include httpd.conf
# Include ports listing
Include ports.conf
#
# The following directives define some format nicknames for use with
# a CustomLog directive (see below).
# If you are behind a reverse proxy, you might want to change %h into %{X-Forwarded-For}i
#
LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined
LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %O" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent
# Include of directories ignores editors' and dpkg's backup files,
# see README.Debian for details.
# Include generic snippets of statements
Include conf.d/
# Include the virtual host configurations:
Include sites-enabled/
<IfModule mod_spamhaus.c>
MS_METHODS POST,PUT,OPTIONS,CONNECT
MS_WhiteList /etc/spamhaus.wl
MS_CacheSize 256
</IfModule>
已加载模块：
core_module (static)
log_config_module (static)
logio_module (static)
mpm_prefork_module (static)
http_module (static)
so_module (static)
alias_module (shared)
auth_basic_module (shared)
authn_file_module (shared)
authz_default_module (shared)
authz_groupfile_module (shared)
authz_host_module (shared)
authz_user_module (shared)
autoindex_module (shared)
cgi_module (shared)
deflate_module (shared)
dir_module (shared)
env_module (shared)
headers_module (shared)
mime_module (shared)
evasive20_module (shared)
negotiation_module (shared)
php5_module (shared)
qos_module (shared)
reqtimeout_module (shared)
rewrite_module (shared)
setenvif_module (shared)
ssl_module (shared)
status_module (shared)
unique_id_module (shared)
Syntax OK
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答案1
由于没有人回答这个问题，所以我希望有人会发现这很有用。
我利用mod_status并观察了实时流量，才解决了这个问题。结果发现，几个网站（几个 Apache）vhosts对一些脚本发出了长时间的自初始化 http 请求php。这些php脚本是一些 Wordpress 安全插件 cron 脚本 - 它们正在进行网站扫描，并且存在一些严重的错误，导致扫描无法终止和成功退出（此信息稍后会公布）。我切断了这些，问题立即消失。
这个故事的寓意是，如果你陷入这样的困境，除了其他检查外：
- 总是首先怀疑脚本语言——它们是常见的嫌疑人
- 利用
mod_status。 - 找到长期存在和/或挂起的脚本。看看能否终止它们