Questions[scl](server)

I have a relatively old server with CentOS 6 on it. The default gcc is 4.4.7 but after some googling, I found I can update this via devtoolset-7. I installed devtoolset-7 via root (i.e. sudo -i), and it installed okay.

Then I did scl enable devtoolkit-7 bash but it dosn't seem to do anything.

[affan@abm-lab ~]$ gcc --version
gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23)
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[affan@abm-lab ~]$ scl enable devtoolset-7 bash

[affan@abm-lab ~]$ gcc --version
gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-23)
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Does anyone know why scl is not enabling a sub environment with the proper variables set?

Trying to create an RPM that uses Python 2.7 on a RHEL 6 machine. I'm using SCL to enable Python2.7 and building the RPM with it fine. However, when I try to install that RPM on a different system after enabling Python 2.7 (scl enable python27 bash then yum localinstall myrpm.rpm), I receive an error stating:

Requires: python(abi) = 2.7
Installed: python-2.6.6-64
    python(abi) = 2.6

Is there something I need to add in the spec file when building the RPM to fix this issue. Or is the issue related to the environment on the machine I'm attempting to install the RPM?

I am setting up a virtualenv based on Python 2.7 in Redhat Enterprise 6 (which ships with 2.6.x by default).

I installed the SCL 2.7 version of Python and then created the virtualenv:

$ scl enable python27 bash
$ cd /my/project
$ virtualenv -v --clear --extra-search-dir=/opt/rh/python27/root/usr/bin/ --python=/opt/rh/python27/root/usr/bin/python virtualenv
$ source virtualenv/bin/acticvate

So far so good. The problems started when I tried to run pip behind my institution's proxy:

$ pip install Werkzeug --proxy proxy.example.org:3128                       
Downloading/unpacking Werkzeug                                                 
Cleaning up...                                                                 
Exception:                                                                     
Traceback (most recent call last):                                             
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/basecommand.py", line 134, in main
    status = self.run(options, args)                                           
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/commands/install.py", line 236, in run
    requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, bundle=self.bundle)
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/req.py", line 1085, in prepare_files
    url = finder.find_requirement(req_to_install, upgrade=self.upgrade)        
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/index.py", line 201, in find_requirement
    page = self._get_page(main_index_url, req)                                 
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/index.py", line 554, in _get_page
    return HTMLPage.get_page(link, req, cache=self.cache)                      
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/index.py", line 671, in get_page
    resp = urlopen(url)                                                        
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/download.py", line 176, in __call__
    response = self.get_opener(scheme=scheme).open(url)                        
  File "/opt/rh/python27/root/usr/lib64/python2.7/urllib2.py", line 404, in open
    response = self._open(req, data)                                           
  File "/opt/rh/python27/root/usr/lib64/python2.7/urllib2.py", line 422, in _open
    '_open', req)                                                              
  File "/opt/rh/python27/root/usr/lib64/python2.7/urllib2.py", line 382, in _call_chain
    result = func(*args)                                                       
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/download.py", line 155, in https_open
    return self.do_open(self.specialized_conn_class, req)                      
  File "/opt/rh/python27/root/usr/lib64/python2.7/urllib2.py", line 1183, in do_open
    h.request(req.get_method(), req.get_selector(), req.data, headers)         
  File "/opt/rh/python27/root/usr/lib64/python2.7/httplib.py", line 1001, in request
    self._send_request(method, url, body, headers)                             
  File "/opt/rh/python27/root/usr/lib64/python2.7/httplib.py", line 1035, in _send_request
    self.endheaders(body)                                                      
  File "/opt/rh/python27/root/usr/lib64/python2.7/httplib.py", line 997, in endheaders
    self._send_output(message_body)                                            
  File "/opt/rh/python27/root/usr/lib64/python2.7/httplib.py", line 850, in _send_output
    self.send(msg)                                                             
  File "/opt/rh/python27/root/usr/lib64/python2.7/httplib.py", line 812, in send
    self.connect()                                                             
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/download.py", line 139, in connect
    match_hostname(self.sock.getpeercert(), self.host)                         
  File "/my/project/virtualenv/lib/python2.7/site-packages/pip/backwardcompat/ssl_match_hostname.py", line 61, in match_hostname
    % (hostname, ', '.join(map(repr, dnsnames))))                              
CertificateError: hostname 'proxy.example.org' doesn't match either of 'www.python.org', 'python.org', 'pypi.python.org', 'docs.python.org', 'testpypi.python.org', 'bug>>>s.python.org', 'wiki.python.org', 'hg.python.org', 'mail.python.org', 'packaging.python.org', 'pythonhosted.org', 'www.pythonhosted.org', 'test.pythonhosted.org', 'us.py>>>con.org', 'id.python.org', 'pypi.io'

I have seen this issue in other questions but none of these seem to apply to my case.

Edit:

E.g. I tried setting environment variables as in https://stackoverflow.com/questions/21468550/pip-not-working-behind-firewall . Other cases were addressing Windows issues.

It may be worth mentioning that this virtualenv won't work if I am not in the scl environment, e.g. if I call python enabling the virtualenv but not scl, it will complain that libpython2.7.so.1.0 cannot be found. I don't know if this is bny design, but I expected all the libraries Python 2.7 depends on to be symlinked or copied in the virtualenv. Maybe something I did wrong in the virtualenv installation?

I've recently discovered software collections and understand how they allow me to install multiple versions of software by introducing a namespace for each collection. On Enterprise Linux, this is neat because I'll be able to keep the the regular stability of my system, while now being able to easily update certain versions of software as they are updated (not just security updates, but features too!)

I'd like my system's main webserver to be httpd 2.4. The version available from centos-sclo-rh software collection is currently 2.4.12, while the version available from base is only 2.4.6. So I installed httpd from that SCL and enabled it:

> scl enable httpd24-httpd bash

And then enabled and started the service using systemctl

> systemctl enable httpd24-httpd
> systemctl start http24-httpd

So I would expect my system should understand that I now have a webserver installed. However, when I try to install phpmyadmin from epel, it still wants to install the standard httpd package from base as a dependency.

Looking in to a bit of the mechanics of rpms, I've just learned that packages can have a Provides line in their spec file listing virtual packages like webserver, and indeed the src rpm for httpd has a Provides: webserver line. I'm guessing that the httpd24-httpd package I obtained from the SCL doesn't have that descriptor.

How can I get my system to recognize the installed and enabled httpd from the SCL provides the webserver virtual package so that it doesn't want to install the httpd package from base to fulfill the webserver virtual dependency?