CentOS - Oct 2020 - Apache HTTPD not picking up environment variables.

I'm trying to install DB2 on a CentOS 7 server.  The problem I'm seeing
is that the Apache httpd server fails to pick up the db2 environment variables. 
On an older version running under CentOS 5 this was done by inserting the
following lines into the httpd start script in /etc/sysconfig/httpd:

if test -f /db2home/db2inst1/sqllib/db2profile; then
  . /db2home/db2inst1/sqllib/db2profile
fi

Under CentOS 7's systemctl system this no longer works. I need a clue as to
where to start looking for where to put this so it will be sourced when the
Apache server starts.  I have googled this and can find nothing relevant.  I
even did a "find / -name httpd -print" and didn't find anything
looking promising.

Thanks for your help

Harold

On Fri, Oct 23, 2020 at 04:27:34PM +0000, Harold Pritchett
wrote:
> I'm trying to install DB2 on a CentOS 7 server.  The problem I'm
> seeing is that the Apache httpd server fails to pick up the db2
> environment variables.  On an older version running under CentOS 5
> this was done by inserting the following lines into the httpd start
> script in /etc/sysconfig/httpd: 
> 
> if test -f /db2home/db2inst1/sqllib/db2profile; then
>   . /db2home/db2inst1/sqllib/db2profile
> fi
> 
> Under CentOS 7's systemctl system this no longer works. I need a
> clue as to where to start looking for where to put this so it will
> be sourced when the Apache server starts.  I have googled this and
> can find nothing relevant.  I even did a "find / -name httpd
-print"
> and didn't find anything looking promising. 
In non-systemd systems, httpd was started by a shell script
(/etc/rc.d/init.d/httpd) which sourced the file /etc/sysconfig/httpd,
so you could embed shell code in the file and it would be evaluated.

In systemd systems, the httpd.service unit has:

EnvironmentFile=/etc/sysconfig/httpd

For systemd units, setting this will cause the systemd unit to read in
the file for variables, but it ignores anything that isn't a simple
'foo=bar' syntax.  It doesn't evaluate shell scripts.


HOWEVER, the logic of your shell script is something that can be
supported by systemd units.  You can say:

EnvironmentFile=-/db2home/db2inst1/sqllib/db2profile

and it will only try to source that file for variables if it exists.

So, what you should do is create a directory and file within it
called:

/etc/systemd/system/httpd.service.d/override.conf

With these two lines in it:

[Service]
EnvironmentFile=-/db2home/db2inst1/sqllib/db2profile

Then run (as root) 'systemctl daemon-reload', and it should
conditionally load the environment variables on startup from that file
if the file exists.

This assumes that /db2home/db2inst1/sqllib/db2profile doesn't have
more shell syntax in it, of course.

See for more details:

https://www.freedesktop.org/software/systemd/man/systemd.exec.html#EnvironmentFile


-- 
Jonathan Billings <billings at negate.org>

Thank you very much.  That did it!  

Hal

-----Original Message-----
From: CentOS <centos-bounces at centos.org> On Behalf Of Jonathan Billings
Sent: Friday, October 23, 2020 1:06 PM
To: CentOS mailing list <centos at centos.org>
Subject: Re: [CentOS] Apache HTTPD not picking up environment variables.

[EXTERNAL SENDER - PROCEED CAUTIOUSLY]


On Fri, Oct 23, 2020 at 04:27:34PM +0000, Harold Pritchett
wrote:
> I'm trying to install DB2 on a CentOS 7 server.  The problem I'm 
> seeing is that the Apache httpd server fails to pick up the db2 
> environment variables.  On an older version running under CentOS 5 
> this was done by inserting the following lines into the httpd start 
> script in /etc/sysconfig/httpd:
>
> if test -f /db2home/db2inst1/sqllib/db2profile; then
>   . /db2home/db2inst1/sqllib/db2profile
> fi
>
> Under CentOS 7's systemctl system this no longer works. I need a clue 
> as to where to start looking for where to put this so it will be 
> sourced when the Apache server starts.  I have googled this and can 
> find nothing relevant.  I even did a "find / -name httpd -print"
> and didn't find anything looking promising.
In non-systemd systems, httpd was started by a shell script
(/etc/rc.d/init.d/httpd) which sourced the file /etc/sysconfig/httpd, so you
could embed shell code in the file and it would be evaluated.

In systemd systems, the httpd.service unit has:

EnvironmentFile=/etc/sysconfig/httpd

For systemd units, setting this will cause the systemd unit to read in the file
for variables, but it ignores anything that isn't a simple 'foo=bar'
syntax.  It doesn't evaluate shell scripts.


HOWEVER, the logic of your shell script is something that can be supported by
systemd units.  You can say:

EnvironmentFile=-/db2home/db2inst1/sqllib/db2profile

and it will only try to source that file for variables if it exists.

So, what you should do is create a directory and file within it
called:

/etc/systemd/system/httpd.service.d/override.conf

With these two lines in it:

[Service]
EnvironmentFile=-/db2home/db2inst1/sqllib/db2profile

Then run (as root) 'systemctl daemon-reload', and it should
conditionally load the environment variables on startup from that file if the
file exists.

This assumes that /db2home/db2inst1/sqllib/db2profile doesn't have more
shell syntax in it, of course.

See for more details:

https://www.freedesktop.org/software/systemd/man/systemd.exec.html#EnvironmentFile


--
Jonathan Billings <billings at negate.org>
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