gyin's questions

我遇到了这样一种情况，即在 Apache/mod_wsgi/Django 部署的服务器上找不到 MySQL 库，尽管仅 Python 就可以正确导入该库。

这是我的 Apache 日志错误：

[Tue Jul 10 12:52:02 2012] [error] [client 127.0.0.1]   File "/remote/projects1/pdrtke/python/lib/python2.6/site-packages/Django-1.3-py2.6.egg/django/utils/importlib.py", line 35, in import_module
[Tue Jul 10 12:52:02 2012] [error] [client 127.0.0.1]     __import__(name)
[Tue Jul 10 12:52:02 2012] [error] [client 127.0.0.1]   File "/remote/projects1/pdrtke/python/lib/python2.6/site-packages/Django-1.3-py2.6.egg/django/db/backends/mysql/base.py", line 14, in <module>
[Tue Jul 10 12:52:02 2012] [error] [client 127.0.0.1]     raise ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
[Tue Jul 10 12:52:02 2012] [error] [client 127.0.0.1] ImproperlyConfigured: Error loading MySQLdb module: libmysqlclient_r.so.16: cannot open shared object file: No such file or directory

我已经尝试过以下方法：

• 检查 Python 解释器是否可以做import MySQLdb：好的
• 检查python manage.py ...需要数据库支持的操作是否有效：好的
• 检查LD_LIBRARY_PATH指向 libmysqlclient_r.so.16 可用的目录：好的
• 附上httpd过程gdb，并做一个show env：LD_LIBRARY_PATH要点libmysqlclient_r.so.16
• 修改envvarsbin/http目录下的文件添加一个export LD_LIBRARY_PATH=...（以防万一）：Ok
• 通过 a 检查ldd libmysqlclient_r.so.16库本身不包含未解决的依赖项
• 检查httpd可执行文件没有设置 setuid 位；这是忽略的有据可查的理由LD_LIBRARY_PATH：好的

这些操作似乎都无法解决我的问题。有什么明显的事情我忘了考虑吗？

我完成了 mod_wsgi 的故障排除，但找不到针对我的分段错误案例的答案。mod_wsgi当模块集成到我的 Apache httpd 服务器中时，我得到以下 coredump 。服务器没有mod_wsgi运行良好。

• 阿帕奇 httpd: 2.2.22
• mod_wsgi：3.3
• 蟒蛇：2.6.7

知道是什么导致了核心转储吗？有没有我可以尝试的事情或解决方法？

核心转储：

Program terminated with signal 11, Segmentation fault.
#0  0x00007fe06c39d206 in wsgi_python_init () from /remote/projects1/pdrtke/install/httpd-2.2.22/modules/mod_wsgi.so
#1  0x00007fe06c3aadb5 in wsgi_hook_child_init () from /remote/projects1/pdrtke/install/httpd-2.2.22/modules/mod_wsgi.so
#2  0x00000000004424db in ap_run_child_init ()
#3  0x000000000047ea35 in child_main ()
#4  0x000000000047ef26 in make_child ()
#5  0x000000000047f198 in perform_idle_server_maintenance ()
#6  0x000000000047f67b in ap_mpm_run ()
#7  0x0000000000429361 in main ()

httpd从源代码编译的二进制文件。（我跑了configure --prefix=...，仅此而已）

> file httpd                                                                                                                                                                                
    httpd: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), for GNU/Linux 2.6.4, dynamically linked (uses shared libs), not stripped
> ldd httpd
    linux-vdso.so.1 =>  (0x00007fffdc5ff000)
    libm.so.6 => /lib64/libm.so.6 (0x00007f33ef7fe000)
    libaprutil-1.so.0 => /remote/projects1/pdrtke/install/httpd-2.2.22/lib/libaprutil-1.so.0 (0x00007f33ef5d4000)
    libexpat.so.1 => /lib64/libexpat.so.1 (0x00007f33ef3aa000)
    libapr-1.so.0 => /remote/projects1/pdrtke/install/httpd-2.2.22/lib/libapr-1.so.0 (0x00007f33ef172000)
    librt.so.1 => /lib64/librt.so.1 (0x00007f33eef69000)
    libcrypt.so.1 => /lib64/libcrypt.so.1 (0x00007f33eed2e000)
    libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f33eeb11000)
    libdl.so.2 => /lib64/libdl.so.2 (0x00007f33ee90d000)
    libc.so.6 => /lib64/libc.so.6 (0x00007f33ee5af000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f33efa54000)

模块 WSGI：

> file mod_wsgi.so       
    mod_wsgi.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, not stripped
> ldd mod_wsgi.so
    linux-vdso.so.1 =>  (0x00007fffb8f0e000)
    libpython2.6.so.1.0 => /usr/lib64/libpython2.6.so.1.0 (0x00007f4c6dd87000)
    libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f4c6db69000)
    libdl.so.2 => /lib64/libdl.so.2 (0x00007f4c6d965000)
    libutil.so.1 => /lib64/libutil.so.1 (0x00007f4c6d762000)
    libm.so.6 => /lib64/libm.so.6 (0x00007f4c6d50b000)
    libc.so.6 => /lib64/libc.so.6 (0x00007f4c6d1ad000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f4c6e37b000)

Python 可执行文件：

> file python
    python: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), for GNU/Linux 2.6.4, dynamically linked (uses shared libs), not stripped
> ldd python
    linux-vdso.so.1 =>  (0x00007fff6a1ff000)
    libpython2.6.so.1.0 => /softntools/opt/Python-2.6/bin/../lib/libpython2.6.so.1.0 (0x00007f14730fc000)
    libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f1472edf000)
    libdl.so.2 => /lib64/libdl.so.2 (0x00007f1472cdb000)
    libutil.so.1 => /lib64/libutil.so.1 (0x00007f1472ad8000)
    libm.so.6 => /lib64/libm.so.6 (0x00007f1472882000)
    libc.so.6 => /lib64/libc.so.6 (0x00007f1472524000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f14733b0000)