Hi,

Recently I upgraded my Apache 1.3.33 webserver to Apache 2.2.4, and ever since, I noticed that it is acting in such a way that it often is VERY greedy with my server's resources. Quite often, when running "top", a list that is as the one that appears at the bottom of this e-mail is shown: indeed pretty much solely httpd instances, that for extended periods of time almost continously pull the CPU to close to 100%, and that also consume a lot of the memory resources... Strangely enough, at other times the CPU load is just slightly above 0%, say 0.4% or so...


Apart from the fact that it "doesn't feel right" to see the CPU for substantial amounts of time, almost constantly close to 100%, there is a further issue, being that sendmail rejects connections when the server load is (too) high. This is very annoying, as e-mail is also a crucial part of the server's functionality, and I don't want sendmail to reject connections, each and every time that Apache goes berserk.

Now, the machine in question, is an AMD-64 machine, and it runs the AMD-64 version of FreeBSD (5.4-release) with a custom kernel. Surely, Apache can be reconfigured such that it doesn't behave so selfishly, and leaves a decent amount of resources for other stuff (such as sendmail) on the machine too.

What I'm basically trying to find out is:
1-Is this normal, or can this perhaps be some (brute force) hack attempt, where something is pounding Apache heavily, trying to find/ exploit some security risk? 2-How can I inspect exactly what each httpd instance is doing (i.e. which request it is serving)? 3-How to best configure Apache 2.2.4 such that it will never use more than a specific amount of the system's resources (e.g. a CPU usage limit of 75%, and a memory limit of say 1GB)? It would be my guess that the amount of "MaxClients" should be lowered, but is that sufficient (note: current httpd-mpm.conf settings apper at the end of this e-mail, and indicate an amount of 150), and will that not somehow (all too) negatively affect the way Apache handles requests? 4-How to perhaps tell sendmail to be a bit more selfish, and stop it from rejecting connections for extended periods of time? (note: we all know just how much "fun" it can be to configure Sendmail :P so for now I've only included (a shortened version of the) RX daemon config file, and hope someone can give me a good pointer for this - or tell me where else to look). 5-When sendmail rejects (incoming) connections, does mail actually get lost, or will it (always) be handled later, when the server is less occupied?

Cheers, and tnx in advance!
Olafo


PS: I hope anyone can give me some good ideas, and for completeness sake, I've copied some additional information that may give an insight into the issues:


1) The Sendmail "rejecting connections" issue:
ps auxww | grep sendmail
root 2259 0.0 0.0 9480 668 ?? Ss 20Apr07 0:38.17 sendmail: rejecting connections on daemon MSA: load average: 59 (sendmail) smmsp 2261 0.0 0.0 13628 760 ?? S 20Apr07 1:40.56 sendmail: running queue: /var/spool/mqueue-rx (sendmail) root 2262 0.0 0.0 9480 704 ?? Ss 20Apr07 0:37.85 sendmail: accepting connections (sendmail) smmsp 2265 0.0 0.0 9344 608 ?? Is 20Apr07 0:01.33 sendmail: Queue [EMAIL PROTECTED]:10:00 for /var/spool/clientmqueue (sendmail) root 91503 0.0 0.0 428 320 p0 D+ 7:23PM 0:00.00 grep sendmail

2) "top" output (partial), during (apparent) heavy load:
last pid: 91504; load averages: 58.76, 59.21, 60.20 up 13+07:02:40 19:24:50
163 processes: 61 running, 102 sleeping
CPU states: 98.8% user, 0.0% nice, 0.4% system, 0.8% interrupt, 0.0% idle
Mem: 1299M Active, 204M Inact, 289M Wired, 63M Cache, 214M Buf, 39M Free
Swap: 2021M Total, 922M Used, 1099M Free, 45% Inuse, 128K In

PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU COMMAND 91459 www 124 0 141M 15136K RUN 0:02 5.52% 5.52% httpd 91352 www 119 0 139M 12596K select 0:14 3.61% 3.61% httpd 91455 www 124 0 167M 41960K RUN 0:03 3.61% 3.61% httpd 91461 www 124 0 141M 15128K RUN 0:03 1.37% 1.37% httpd 91126 www 124 0 158M 19520K RUN 1:46 0.83% 0.83% httpd 91139 www 124 0 158M 19532K RUN 1:43 0.83% 0.83% httpd 91152 www 124 0 195M 19396K RUN 1:40 0.83% 0.83% httpd 91175 www 124 0 170M 44524K RUN 1:02 0.83% 0.83% httpd 90387 www 124 0 170M 27548K RUN 5:19 0.78% 0.78% httpd 90529 www 124 0 195M 24584K RUN 4:49 0.78% 0.78% httpd 90665 www 124 0 167M 41804K RUN 3:29 0.78% 0.78% httpd 90897 www 124 0 181M 23964K RUN 2:10 0.78% 0.78% httpd 91069 www 124 0 158M 20128K RUN 1:53 0.78% 0.78% httpd 91100 www 124 0 162M 21284K RUN 1:49 0.78% 0.78% httpd 91125 www 124 0 162M 22976K RUN 1:46 0.78% 0.78% httpd 91092 www 124 0 162M 23972K RUN 1:45 0.78% 0.78% httpd 91133 www 124 0 162M 17928K RUN 1:44 0.78% 0.78% httpd 91135 www 124 0 158M 19668K RUN 1:43 0.78% 0.78% httpd 89973 www 124 0 158M 18212K RUN 8:15 0.73% 0.73% httpd 90269 www 124 0 158M 19940K RUN 6:40 0.73% 0.73% httpd 90254 www 124 0 162M 25584K RUN 5:58 0.73% 0.73% httpd 90464 www 124 0 195M 27464K RUN 4:51 0.73% 0.73% httpd 91027 www 124 0 181M 24104K RUN 2:09 0.73% 0.73% httpd 91072 www 124 0 158M 17456K RUN 1:53 0.73% 0.73% httpd 91098 www 124 0 158M 19780K RUN 1:48 0.73% 0.73% httpd 91119 www 124 0 162M 23436K RUN 1:45 0.73% 0.73% httpd 91121 www 124 0 162M 23088K RUN 1:45 0.73% 0.73% httpd 91130 www 124 0 158M 19880K RUN 1:44 0.73% 0.73% httpd 91145 www 124 0 158M 19788K RUN 1:42 0.73% 0.73% httpd 91141 www 124 0 181M 23852K RUN 1:40 0.73% 0.73% httpd 91131 www 124 0 167M 41904K RUN 0:37 0.73% 0.73% httpd 91312 www 124 0 157M 31908K RUN 0:37 0.73% 0.73% httpd 89962 www 124 0 179M 35048K RUN 10:58 0.68% 0.68% httpd 89964 www 124 0 179M 39184K RUN 9:51 0.68% 0.68% httpd

3) "apachectl -l" output:
Compiled in modules:
  core.c
  prefork.c
  http_core.c
  mod_so.c

4) Apache's usr/local/etc/apache22/extra/httpd-mpm.conf settings regarding the amount of clients etc. (note: I assume the "prefork MPM" to be the one that is used, so I removed the BeOS, NetWare and OS2 MPM configuration stuff, to save space):
#
# Server-Pool Management (MPM specific)
#

#
# PidFile: The file in which the server should record its process
# identification number when it starts.
#
# Note that this is the default PidFile for most MPMs.
#
<IfModule !mpm_netware_module>
    PidFile /var/run/httpd.pid
</IfModule>

#
# The accept serialization lock file MUST BE STORED ON A LOCAL DISK.
#
<IfModule !mpm_winnt_module>
<IfModule !mpm_netware_module>
LockFile /var/log/accept.lock
</IfModule>
</IfModule>

#
# Only one of the below sections will be relevant on your
# installed httpd.  Use "apachectl -l" to find out the
# active mpm.
#

# 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
# MaxClients: maximum number of simultaneous client connections
# 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 # MaxRequestsPerChild: maximum number of requests a server process serves
<IfModule mpm_worker_module>
    StartServers          2
    MaxClients          150
    MinSpareThreads      25
    MaxSpareThreads      75
    ThreadsPerChild      25
    MaxRequestsPerChild   0
</IfModule>

# [cut BeOS MPM, NetWare MPM, and OS/2 MPM configuration, as these should not be in use]


5) /etc/mail/<servername>-rx.mc:
millennics# more ./millennics.nl-rx.mc
dnl To be used for MTA-RX, the first MTA instance (receiving mail)

dnl Insert here the usual .mc preamble, including OSTYPE and DOMAIN calls.

divert(-1)

#
#  [cut the general text]
#

divert(0)
VERSIONID(`$FreeBSD: src/etc/sendmail/freebsd.mc,v 1.28 2003/04/18 01:25:41 gshapiro Exp $')
OSTYPE(freebsd5)
DOMAIN(generic)
dnl Specify here also access controls, relayable domains, anti-spam measures dnl including milter settings if needed, mail submission settings, client dnl authentication, resource controls, maximum mail size and header size,
dnl confMIN_FREE_BLOCKS, and other settings needed for receiving mail.
dnl
dnl NOTE:
dnl   confMIN_FREE_BLOCKS at MTA-RX should be kept higher than the same
dnl   setting at MTA-TX, to quench down clients when disk space is low,
dnl   and not to stop processing the already received mail.
dnl
dnl In particular, here are some settings to be considered:
dnl   ( see also http://www.sendmail.org/m4/anti_spam.html )
dnl
dnl FEATURE(`access_db',`hash -T<TMPF> /etc/mail/access.db')
dnl VIRTUSER_DOMAIN(`sub1.example.com')dnl  list valid users here
dnl VIRTUSER_DOMAIN(`sub2.example.com')dnl  list valid users here
dnl FEATURE(`virtusertable', `hash /etc/mail/virtusertable')
dnl define(`confUSERDB_SPEC', `/etc/mail/userdb.db')
dnl FEATURE(`blacklist_recipients')
dnl INPUT_MAIL_FILTER(...)
dnl define(`confPRIVACY_FLAGS', `noexpn,novrfy,authwarnings') nobodyreturn ?
dnl define(`confDONT_PROBE_INTERFACES')
dnl undefine(`USE_CW_FILE')dnl cancel use_cw_file feature, no class {w} extras dnl MASQUERADE_AS(...) FEATURE(`allmasquerade') FEATURE (`masquerade_envelope')
dnl define(`confTO_IDENT', `0')dnl  Disable IDENT
dnl define(`confMAX_MESSAGE_SIZE',`10485760')
dnl define(`confMAX_MIME_HEADER_LENGTH', `256/128')
dnl define(`confNO_RCPT_ACTION', `add-to-undisclosed')
dnl FEATURE(`nocanonify', ...)
dnl define(`confBIND_OPTS', ...)
dnl define(`confTO_RESOLVER_*... )
dnl define(`confDELAY_LA,    8)
dnl define(`confREFUSE_LA', 12)
dnl define(`confMIN_FREE_BLOCKS', `10000')
dnl define(`confDEF_USER_ID', ...)

FEATURE(access_db, `hash -o -T<TMPF> /etc/mail/access')
FEATURE(blacklist_recipients)
FEATURE(local_lmtp)
FEATURE(mailertable, `hash -o /etc/mail/mailertable')
FEATURE(virtusertable, `hash -o /etc/mail/virtusertable')

dnl [cut relaying, and black(hole) lists, etc., as these are all commented out]

dnl Uncomment the first line to change the location of the default
dnl /etc/mail/local-host-names and comment out the second line.
dnl define(`confCW_FILE', `-o /etc/mail/sendmail.cw')
define(`confCW_FILE', `-o /etc/mail/local-host-names')

dnl Uncomment both of the following lines to listen on IPv6 as well as IPv4
dnl DAEMON_OPTIONS(`Name=IPv4, Family=inet')
dnl DAEMON_OPTIONS(`Name=IPv6, Family=inet6')

define(`confBIND_OPTS', `WorkAroundBrokenAAAA')
define(`confNO_RCPT_ACTION', `add-to-undisclosed')
define(`confPRIVACY_FLAGS', `authwarnings,noexpn,novrfy')

define(`confRUN_AS_USER',`smmsp:smmsp')dnl Drop privileges (see SECURITY NOTE)

define(`confPID_FILE', `/var/run/sendmail-rx.pid')dnl Non-default pid file
define(`STATUS_FILE', `/etc/mail/stat-rx')dnl    Non-default stat file
define(`QUEUE_DIR', `/var/spool/mqueue-rx')dnl   Non-default queue area
define(`confQUEUE_SORT_ORDER',`Modification')dnl Modif or Random are reasonable

dnl Match the number of queue runners (R=) to the number of amavisd- new child
dnl processes ($max_servers). 2 to 7 OK, 10 is plenty, 20 is too many
QUEUE_GROUP(`mqueue', `P=/var/spool/mqueue-rx, R=2, F=f')dnl

dnl Direct all mail to be forwarded to amavisd-new at 127.0.0.1:10024
FEATURE(stickyhost)dnl Keep envelope addr "[EMAIL PROTECTED]" when fwd to MAIL_HUB define(`MAIL_HUB', `esmtp:[127.0.0.1]')dnl Forward all local mail to amavisd define(`SMART_HOST',`esmtp:[127.0.0.1]')dnl Forward all other mail to amavisd

define(`confDELIVERY_MODE',`q')dnl Delivery mode: queue only (a must,
dnl  ... otherwise the advantage of this setup of being able to specify
dnl  ... the number of queue runners is lost)
define(`ESMTP_MAILER_ARGS',`TCP $h 10024')dnl To tcp port 10024 instead of 25
MODIFY_MAILER_FLAGS(`ESMTP', `+z')dnl  Speak LMTP (this is optional)
define(`SMTP_MAILER_MAXMSGS',`10')dnl Max no. of msgs in a single connection define(`confTO_DATAFINAL',`20m')dnl 20 minute timeout for content checking DAEMON_OPTIONS(`Name=MTA-RX')dnl Daemon name used in logged messages

dnl Disable local delivery, as all local mail will go to MAIL_HUB
undefine(`ALIAS_FILE')dnl No aliases file, all local mail goes to MAIL_HUB
define(`confFORWARD_PATH')dnl Empty search path for .forward files
undefine(`UUCP_RELAY')dnl
undefine(`BITNET_RELAY')dnl
undefine(`DECNET_RELAY')dnl

MAILER(smtp)




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