今天在CentOS7.6的系统上，自编译安装了OpenSSL 1.1.1和CURL 7.63并添到系统环境之后，发现使用yum安装出现报错，如下：
[root@Monitor ~]# yum install -y libffi-devel
There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:
/usr/lib64/python2.7/site-packages/pycurl.so: undefined symbol: CRYPTO_num_locks
Please install a package which provides this module, or
verify that the module is installed correctly.
It's possible that the above module doesn't match the
current version of Python, which is:
2.7.5 (default, Oct 30 2018, 23:45:53)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-36)]
If you cannot solve this problem yourself, please go to
the yum faq at:
http://yum.baseurl.org/wiki/Faq
[root@Monitor ~]# ldd /usr/lib64/python2.7/site-packages/pycurl.so
linux-vdso.so.1 => (0x00007ffc9b949000)
libcurl.so.4 => /usr/local/curl/lib/libcurl.so.4 (0x00007f2e00937000)
libpython2.7.so.1.0 => /lib64/libpython2.7.so.1.0 (0x00007f2e0056b000)
libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f2e0034f000)
libc.so.6 => /lib64/libc.so.6 (0x00007f2dfff82000)
libssl.so.1.1 => /usr/local/openssl/lib/libssl.so.1.1 (0x00007f2dffcf0000)
libcrypto.so.1.1 => /usr/local/openssl/lib/libcrypto.so.1.1 (0x00007f2dff809000)
libz.so.1 => /usr/local/lib/libz.so.1 (0x00007f2dff5ee000)
libdl.so.2 => /lib64/libdl.so.2 (0x00007f2dff3ea000)
libutil.so.1 => /lib64/libutil.so.1 (0x00007f2dff1e7000)
libm.so.6 => /lib64/libm.so.6 (0x00007f2dfeee5000)
/lib64/ld-linux-x86-64.so.2 (0x00007f2e00dbb000)情况很明显，是系统库动态链接调用到新装的CURL上，而导致部分定义未识别。就和之前的 let’s encrypt的错误一样，解决也和其一样，不过由于我自定义目录的关系，直接升级安装会报错，找不到ssl头：
[root@Monitor ~]# pip install --upgrade pycurl
Looking in indexes: http://mirrors.cloud.aliyuncs.com/pypi/simple/
Collecting pycurl
Downloading http://mirrors.cloud.aliyuncs.com/pypi/packages/e8/e4/0dbb8735407189f00b33d84122b9be52c790c7c3b25286826f4e1bdb7bde/pycurl-7.43.0.2.tar.gz (214kB)
100% |████████████████████████████████| 215kB 17.4MB/s
Building wheels for collected packages: pycurl
Running setup.py bdist_wheel for pycurl ... error
Complete output from command /usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-install-WJPkE9/pycurl/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /tmp/pip-wheel-5kWHm3 --python-tag cp27:
Using curl-config (libcurl 7.63.0)
running bdist_wheel
running build
running build_py
creating build
creating build/lib.linux-x86_64-2.7
creating build/lib.linux-x86_64-2.7/curl
copying python/curl/__init__.py -> build/lib.linux-x86_64-2.7/curl
running build_ext
building 'pycurl' extension
creating build/temp.linux-x86_64-2.7
creating build/temp.linux-x86_64-2.7/src
gcc -pthread -fno-strict-aliasing -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -DNDEBUG -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -fPIC -DPYCURL_VERSION="7.43.0.2" -DHAVE_CURL_SSL=1 -DHAVE_CURL_OPENSSL=1 -DHAVE_CURL_SSL=1 -I/usr/local/curl/include -I/usr/include/python2.7 -c src/docstrings.c -o build/temp.linux-x86_64-2.7/src/docstrings.o
In file included from src/docstrings.c:4:0:
src/pycurl.h:164:28: fatal error: openssl/ssl.h: No such file or directory
# include <openssl/ssl.h>
^
compilation terminated.
error: command 'gcc' failed with exit status 1
----------------------------------------
Failed building wheel for pycurl
Running setup.py clean for pycurl
Failed to build pycurl
Installing collected packages: pycurl
Found existing installation: pycurl 7.19.0
Cannot uninstall 'pycurl'. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.添加参数即可解决：
[root@Monitor ~]# CPPFLAGS=-I/usr/local/openssl/include/ LDFLAGS=-L/usr/local/openssl/lib/ pip install --upgrade pycurl --ignore-installed pycurl
Looking in indexes: http://mirrors.cloud.aliyuncs.com/pypi/simple/
Collecting pycurl
Installing collected packages: pycurl
Successfully installed pycurl-7.43.0.2
[root@Monitor ~]# 之后即可正常使用yum命令。