Discussion :

[vodkline]

coucou tout le monde
j'ai un petit serveur web qui fonctionne sous apache
la configuration est la suivante :

ram : 256 mo
processeur : 1/4 core (CPU 2.3 Ghz)

le problème c'est que le site est souvent inaccessible et je n'ai meme pu acces en ssh dessus lors de ces plantages

j'en conclu que cela vien d'apache car avant de l'installé , aucun soucis et depuis qu'il est installé cela plante régulièrement

quelqun aurai une idée pour m'aider ?

ps : j'ai installé apache2 via : aptitude install apache2

[Invité]

Salut,

Tu pourrais déja commencer par regarder dans les logs systèmes et apaches (/var/log) pour essayer de comprendre ce qu'il se passe.

peux-être également vérifier si un filesystem important ne sature pas bloquant ainisi le système et les services.

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df -h

[Chuck_Norris]

Il est possible que la RAM de ton VPS soit saturée, 256 Mo de RAM ce n'est pas beaucoup, surtout si tu exécutes PHP avec Apache.

Contrôle la mémoire disponible avec

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free -m

La seconde ligne (+/- buffer cache) est la plus importante, elle indique la mémoire utilisée hors cache, s'il ne reste presque plus de mémoire sur cette ligne-là, c'est que la RAM est insuffisante. La troisième ligne indique la swap, son utilisation devrait être très faible et idéalement à 0. Si tu vois un truc genre plus de 20, alors pareil, RAM insuffisante. Il faudra alors paramétrer le système et les logiciels pour consommer moins de mémoire, ou augmenter la mémoire du système.

[vodkline]

le resulat de la commande

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free -m

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root@baptiste:/etc# free -m
             total       used       free     shared    buffers     cached
Mem:           256         58        197          0          0          0
-/+ buffers/cache:         58        197
Swap:            0          0          0

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df -h

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Filesystem            Size  Used Avail Use% Mounted on
/dev/simfs             50G  587M   50G   2% /
tmpfs                 128M     0  128M   0% /lib/init/rw
tmpfs                 128M     0  128M   0% /dev/shm

et pour les logs apache2

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[Fri Mar 02 12:11:00 2012] [notice] Apache/2.2.16 (Debian) PHP/5.3.3-7+squeeze3 with Suhosin-Patch configured -- resuming normal operations
[Fri Mar 02 12:11:06 2012] [error] [client 83.198.104.101] File does not exist: /var/www/favicon.ico
[Fri Mar 02 12:11:06 2012] [error] [client 83.198.104.101] File does not exist: /var/www/favicon.ico
[Fri Mar 02 13:33:20 2012] [error] [client 91.121.4.141] client sent HTTP/1.1 request without hostname (see RFC2616 section 14.23): /w00tw00t.at.ISC.SANS.DFind:)
[Fri Mar 02 13:39:46 2012] [error] [client 119.63.196.75] File does not exist: /var/www/robots.txt
[Fri Mar 02 13:48:12 2012] [error] [client 66.249.67.199] File does not exist: /var/www/robots.txt
[Fri Mar 02 13:48:40 2012] [error] [client 83.198.104.101] File does not exist: /var/www/favicon.ico
[Fri Mar 02 13:48:40 2012] [error] [client 83.198.104.101] File does not exist: /var/www/favicon.ico
[Fri Mar 02 13:57:32 2012] [error] [client 83.198.104.101] File does not exist: /var/www/favicon.ico
[Fri Mar 02 13:57:33 2012] [error] [client 83.198.104.101] File does not exist: /var/www/favicon.ico
[Fri Mar 02 13:57:33 2012] [error] [client 83.198.104.101] File does not exist: /var/www/favicon.ico
[Fri Mar 02 15:57:01 2012] [notice] caught SIGTERM, shutting down
[Fri Mar 02 15:57:10 2012] [notice] Apache/2.2.16 (Debian) configured -- resuming normal operations
[Fri Mar 02 15:57:10 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Fri Mar 02 15:57:10 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Fri Mar 02 15:57:12 2012] [alert] No active workers found... Apache is exiting!
[Fri Mar 02 15:58:08 2012] [warn] pid file /var/run/apache2.pid overwritten -- Unclean shutdown of previous Apache run?
[Fri Mar 02 15:58:08 2012] [notice] Apache/2.2.16 (Debian) configured -- resuming normal operations
[Fri Mar 02 15:58:08 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Fri Mar 02 15:58:08 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Fri Mar 02 15:58:10 2012] [alert] No active workers found... Apache is exiting!
[Fri Mar 02 15:59:09 2012] [notice] Apache/2.2.16 (Debian) configured -- resuming normal operations
[Fri Mar 02 15:59:09 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create listener thread
[Fri Mar 02 15:59:09 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Fri Mar 02 15:59:11 2012] [alert] No active workers found... Apache is exiting!
[Sat Mar 03 11:19:00 2012] [notice] Apache/2.2.16 (Debian) configured -- resuming normal operations
[Sat Mar 03 11:19:00 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sat Mar 03 11:19:00 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sat Mar 03 11:19:02 2012] [alert] No active workers found... Apache is exiting!

[Invité]

Hello,

En effet d'après les logs apaches, il semble y avoir trop de threads crées par rapport au nombres de threads que le système peut supporter. C'est la cause des plantages de ton service apache.

Ton apache utilise le module worker qui génère plusieurs threads par process apache.

Il va donc falloir adapter (diminuer) les valeurs dans la section du mpm_worker_module.c qui se trouve dans /etc/apache2/apache2.conf => Peux-tu déjà commencer par fournir les valeurs de cette section?

Peux-tu également fournir la limit maximal de thread sur ton système?

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cat /proc/sys/kernel/threads-max

[vodkline]

pour le fichier apache2.conf

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#
# Based upon the NCSA server configuration files originally by Rob McCool.
#
# This is the main Apache server configuration file.  It contains the
# configuration directives that give the server its instructions.
# See http://httpd.apache.org/docs/2.2/ for detailed information about
# the directives.
#
# Do NOT simply read the instructions in here without understanding
# what they do.  They're here only as hints or reminders.  If you are unsure
# consult the online docs. You have been warned.  
#
# The configuration directives are grouped into three basic sections:
#  1. Directives that control the operation of the Apache server process as a
#     whole (the 'global environment').
#  2. Directives that define the parameters of the 'main' or 'default' server,
#     which responds to requests that aren't handled by a virtual host.
#     These directives also provide default values for the settings
#     of all virtual hosts.
#  3. Settings for virtual hosts, which allow Web requests to be sent to
#     different IP addresses or hostnames and have them handled by the
#     same Apache server process.
#
# Configuration and logfile names: If the filenames you specify for many
# of the server's control files begin with "/" (or "drive:/" for Win32), the
# server will use that explicit path.  If the filenames do *not* begin
# with "/", the value of ServerRoot is prepended -- so "foo.log"
# with ServerRoot set to "/etc/apache2" will be interpreted by the
# server as "/etc/apache2/foo.log".
#
 
### Section 1: Global Environment
#
# The directives in this section affect the overall operation of Apache,
# such as the number of concurrent requests it can handle or where it
# can find its configuration files.
#
 
#
# ServerRoot: The top of the directory tree under which the server's
# configuration, error, and log files are kept.
#
# NOTE!  If you intend to place this on an NFS (or otherwise network)
# mounted filesystem then please read the LockFile documentation (available
# at <URL:http://httpd.apache.org/docs/2.2/mod/mpm_common.html#lockfile>);
# you will save yourself a lot of trouble.
#
# Do NOT add a slash at the end of the directory path.
#
#ServerRoot "/etc/apache2"
 
#
# 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 15
 
##
## 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
# 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
# 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
# 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
# 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_event_module>
    StartServers          2
    MaxClients          150
    MinSpareThreads      25
    MaxSpareThreads      75 
    ThreadLimit          64
    ThreadsPerChild      25
    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.
#
DefaultType text/plain
 
 
#
# 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/

et pour la limite maximal de thread

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513692

autant comprendre ce que je fais : c'est quoi concretement un thread?

[Invité]

Ok,

Pourrais-tu adapter les valeurs suivantes de la sorte. On va voir si le problème persiste ou pas.

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<IfModule mpm_worker_module>
    StartServers          2
    MinSpareThreads      12
    MaxSpareThreads      30 
    ThreadLimit          32
    ThreadsPerChild      12
    MaxClients          75
    MaxRequestsPerChild   0
</IfModule>

Concernant les thread, tu as une explication relativement détaillée à ce sujet sur wikipedia

http://fr.wikipedia.org/wiki/Thread_(informatique)

[vodkline]

voila les logs apres modification

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[Sun Mar 04 09:04:38 2012] [notice] Apache/2.2.16 (Debian) configured -- resuming normal operations
[Sun Mar 04 09:04:38 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create listener thread
[Sun Mar 04 09:04:38 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sun Mar 04 09:04:40 2012] [alert] No active workers found... Apache is exiting!
[Sun Mar 04 09:04:55 2012] [warn] pid file /var/run/apache2.pid overwritten -- Unclean shutdown of previous Apache run?
[Sun Mar 04 09:04:55 2012] [notice] Apache/2.2.16 (Debian) configured -- resuming normal operations
[Sun Mar 04 09:04:55 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sun Mar 04 09:04:58 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sun Mar 04 09:05:00 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sun Mar 04 09:05:02 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sun Mar 04 09:05:04 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sun Mar 04 09:05:06 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sun Mar 04 09:05:08 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sun Mar 04 09:05:10 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread
[Sun Mar 04 09:05:12 2012] [alert] (11)Resource temporarily unavailable: apr_thread_create: unable to create worker thread

et voila ce que j'obtien dans le shell quand je redemare le service :

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Starting web server: apache2WARNING: MaxClients (75) is not an integer multiple
 of ThreadsPerChild (12), lowering MaxClients to 72
 for a maximum of 6 child processes,

[Invité]

Salut,

Le message que l'on voit lors du démarrage de service est simplement un warning indiquant que la valeur de MaxClients doit être un multiple de la valeur de ThtreadsPerChild à savoir un multiple de 12 dans ce cas-ci. Apache l'ajuste automatiquement MaxClients à 72. (6 process et pour chaque process 12 threads).

Pourrais-tu encore baisser la valeur de threadsPerChild à 2 et adapter la valeur de MaxClients pour qu'elle soit à un multiple de 2? (32 par exemple).

Peux-tu également me fournir la liste des packages installés sur ton système lié à apache2?

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dpkg -l  | grep -i apache2

[vodkline]

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ii  apache2                                                2.2.16-6+squeeze6            Apache HTTP Server metapackage
ii  apache2-mpm-worker                                     2.2.16-6+squeeze6            Apache HTTP Server - high speed threaded model
ii  apache2-utils                                          2.2.16-6+squeeze4            utility programs for webservers
ii  apache2.2-bin                                          2.2.16-6+squeeze6            Apache HTTP Server common binary files
ii  apache2.2-common                                       2.2.16-6+squeeze6            Apache HTTP Server common files
rc  libapache2-mod-php5                                    5.3.3-7+squeeze3             server-side, HTML-embedded scripting language (Apache 2 module)

Pourrais-tu encore baisser la valeur de threadsPerChild à 2

c'"est encore pire

[Invité]

C'est encore pire? càd?

Pourrais-tu désinstaller le pacakge apache2-mpm-worker et installer apache2-mpm-prefork. histoire de voir ce que ça donne avec la version non-threadé d'apache?

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aptitude remove apache2-mpm-worker && aptitude install apache2-mpm-prefork

D'après la configuration que tu indiques, Je suppose que ton apache tourne sur un vps? Chez quel hébergeur est-il? Quel est l'usage que tu en fais de ton service apache?

[vodkline]

sa a l'air de marché impeccable , ce VPS me permet de maintenir en ligne mon site pour mon association
mon hebergeur est "Gheberg"