I must say that I am not the guy that set up the server, but the poor sap tasked with finding out what is happening for the time being. I only have a rough knowledge about apache and linux, so please bear with me...
O problema
Um dos nossos servidores apache desligado (principalmente durante a noite) e não consegue recuperar e iniciar o backup novamente, sem ninguém realmente dizendo isso.
Pelo que eu posso encontrar, o interessante aqui é a seguinte linha nos logs de erro do apache;
[Wed Apr 15 03:43:02.114879 2015] [mpm_prefork:notice] [pid 25778] AH00171: Graceful restart requested, doing restart
Depois do que vem um longo stacktrace muito , aqui estão as primeiras linhas:
*** Error in '/usr/sbin/httpd': free(): invalid pointer: 0x00007f581d5c13c0 ***
======= Backtrace: =========
/lib64/libc.so.6(+0x7d19d)[0x7f583b69519d]
/etc/httpd/modules/libphp5.so(php_module_shutdown+0x2b)[0x7f58301d255b]
/etc/httpd/modules/libphp5.so(php_module_shutdown_wrapper+0x9)[0x7f58301d2619]
[...]
O backtrace continua por um tempo, mas o interessante aqui é que, entre isso, o Error in /usr/sbin/httpd [...] se repete 5 vezes, até a última mensagem ser
[Wed Apr 15 03:43:02.269626 2015] [core:notice] [pid 25778] AH00060: seg fault or similar nasty error detected in the parent process
A próxima mensagem é no próximo dia eu inicializando o servidor novamente;
[Wed Apr 15 08:14:46.200884 2015] [core:notice] [pid 30326] SELinux policy enabled; httpd running as context system_u:system_r:httpd_t:s0
[Wed Apr 15 08:14:46.215410 2015] [suexec:notice] [pid 30326] AH01232: suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Wed Apr 15 08:14:46.235346 2015] [auth_digest:notice] [pid 30326] AH01757: generating secret for digest authentication ...
[Wed Apr 15 08:14:46.236045 2015] [lbmethod_heartbeat:notice] [pid 30326] AH02282: No slotmem from mod_heartmonitor
[Wed Apr 15 08:14:46.280992 2015] [core:warn] [pid 30326] AH00098: pid file /run/httpd/httpd.pid overwritten -- Unclean shutdown of previous Apache run?
[Wed Apr 15 08:14:46.284919 2015] [mpm_prefork:notice] [pid 30326] AH00163: Apache/2.4.6 (CentOS) PHP/5.4.16 configured -- resuming normal operations
[Wed Apr 15 08:14:46.284939 2015] [core:notice] [pid 30326] AH00094: Command line: '/usr/sbin/httpd -D FOREGROUND'
Pensamentos
Do meu ponto de vista, o módulo prefork de alguma forma solicita que o processo do apache (ou um deles?) desliga. Isso falha, e em troca as coisas inteiras simplesmente quebram horrivelmente.
Perguntas
Em primeiro lugar: A minha análise - que o problema de travar o servidor é o módulo prefork - corret?
Devo apenas desativar o módulo prefork? Não vejo como depurar / ajudar um erro de memória dentro do próprio software.
Quais implicações tem quando desabilito este módulo?
Informações da versão
Linux version 3.10.0-123.13.2.el7.x86_64 ([email protected]) (gcc version 4.8.2 20140120 (Red Hat 4.8.2-16) (GCC) )
Server version: Apache/2.4.6 (CentOS)
Server built: Jan 12 2015 13:22:31
Server's Module Magic Number: 20120211:23
Server loaded: APR 1.4.8, APR-UTIL 1.5.2
Compiled using: APR 1.4.8, APR-UTIL 1.5.2
Architecture: 64-bit
Server MPM: prefork
threaded: no
forked: yes (variable process count)
Server compiled with....
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
-D APR_USE_SYSVSEM_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D DYNAMIC_MODULE_LIMIT=256
-D HTTPD_ROOT="/etc/httpd"
-D SUEXEC_BIN="/usr/sbin/suexec"
-D DEFAULT_PIDLOG="/run/httpd/httpd.pid"
-D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="conf/mime.types"
-D SERVER_CONFIG_FILE="conf/httpd.conf"
Respostas aos comentários
cron
Não há /etc/cron.d/dailyjobs , mas apenas um script 0hourly , que executa os scripts por hora 0anacron , 0yum-hourly.cron e dellrda.cron - Nenhum deles parece fazer nada relacionado ao apache (IMHO)
/etc/logrotate.d/httpd
/var/log/httpd/*log {
missingok
notifempty
sharedscripts
delaycompress
postrotate
/bin/systemctl reload httpd.service > /dev/null 2>/dev/null || true
endscript
}
Recarregamento manual
/bin/systemctl reload httpd.service
Traz o seguinte resultado
Job for httpd.service failed. See 'systemctl status httpd.service' and 'journalctl -xn' for details.
E no error_log as mesmas mensagens acima são mostradas.
Um rápido systemctl status httpd.service revela:
httpd.service - The Apache HTTP Server
Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled)
Active: failed (Result: signal) since Fri 2015-04-17 12:26:36 CEST; 8s ago
Process: 8828 ExecStop=/bin/kill -WINCH ${MAINPID} (code=exited, status=0/SUCCESS)
Process: 8826 ExecReload=/usr/sbin/httpd $OPTIONS -k graceful (code=exited, status=0/SUCCESS)
Process: 8767 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=killed, signal=ABRT)
Main PID: 8767 (code=killed, signal=ABRT)
Status: "Total requests: 0; Current requests/sec: 0; Current traffic: 0 B/sec"
apachectl -M
Loaded Modules:
core_module (static)
so_module (static)
http_module (static)
access_compat_module (shared)
actions_module (shared)
alias_module (shared)
allowmethods_module (shared)
auth_basic_module (shared)
auth_digest_module (shared)
authn_anon_module (shared)
authn_core_module (shared)
authn_dbd_module (shared)
authn_dbm_module (shared)
authn_file_module (shared)
authn_socache_module (shared)
authz_core_module (shared)
authz_dbd_module (shared)
authz_dbm_module (shared)
authz_groupfile_module (shared)
authz_host_module (shared)
authz_owner_module (shared)
authz_user_module (shared)
autoindex_module (shared)
cache_module (shared)
cache_disk_module (shared)
data_module (shared)
dbd_module (shared)
deflate_module (shared)
dir_module (shared)
dumpio_module (shared)
echo_module (shared)
env_module (shared)
expires_module (shared)
ext_filter_module (shared)
filter_module (shared)
headers_module (shared)
include_module (shared)
info_module (shared)
log_config_module (shared)
logio_module (shared)
mime_magic_module (shared)
mime_module (shared)
negotiation_module (shared)
remoteip_module (shared)
reqtimeout_module (shared)
rewrite_module (shared)
setenvif_module (shared)
slotmem_plain_module (shared)
slotmem_shm_module (shared)
socache_dbm_module (shared)
socache_memcache_module (shared)
socache_shmcb_module (shared)
status_module (shared)
substitute_module (shared)
suexec_module (shared)
unique_id_module (shared)
unixd_module (shared)
userdir_module (shared)
version_module (shared)
vhost_alias_module (shared)
dav_module (shared)
dav_fs_module (shared)
dav_lock_module (shared)
lua_module (shared)
mpm_prefork_module (shared)
proxy_module (shared)
lbmethod_bybusyness_module (shared)
lbmethod_byrequests_module (shared)
lbmethod_bytraffic_module (shared)
lbmethod_heartbeat_module (shared)
proxy_ajp_module (shared)
proxy_balancer_module (shared)
proxy_connect_module (shared)
proxy_express_module (shared)
proxy_fcgi_module (shared)
proxy_fdpass_module (shared)
proxy_ftp_module (shared)
proxy_http_module (shared)
proxy_scgi_module (shared)
systemd_module (shared)
cgi_module (shared)
php5_module (shared)