Compiline ISC DHCP on Redhat

[Bryan J. Smith]

Nathan McDavit-Van Fleet wrote:
> I read that the redhat version of ISC DHCP is “optimized”
> for redhat.

Red Hat customers pay for 7+ years of sustaining engineering instead
of rebases so their existing configuration files work for 7+ years.
Rebases are avoided at all costs, if possible, to mitigate any risk
and impact to deployed environments.  Rebasing is easy to do, and why
many non-enterprise distributions use such an approach.  Enterprise
distributions backport security and other fixes, so existing, deployed
systems and configuration files (on literally thousands of systems) are
not impacted over many, many years.

For more on this approach, see this document:  
  http://www.redhat.com/security/updates/backporting/  

For more on the 7+ year lifecycle, see this document:  
  http://www.redhat.com/security/updates/errata/  

Nathan McDavit-Van Fleet wrote:
> However, the package on Redhat is 3.0.5 and I wanted to try 4.1.1.  

With regards to DHCP 3.0.x, Red Hat Enterprise Linux release 5 shipped
with a heavily modified 3.0.4 with many features and support added.  It
was rebased with some additions in 3.0.5 where it remains today.

Red Hat Enterprise Linux release 6 Beta 2 is testing with 4.1.1.

Red Hat does take Requests for Enhancement (RFE) through Phase I, which
Red Hat Enterprise Linux release 5 is still under.  Red Hat will sometimes
release a "Tech Preview" or even a supported "concurrent" release late
during Phase I.  The "concurrent" errata approach does not replace the
release version, but offers a newer version that does not conflict, so
existing customers relying on the old version are not impacted.

E.g., the package name would be something like dhcp4-4.1.1-P1, in addition
to the release dhcp-3.0.5 version, version appended to the package name
portion (in addition to the full package version after it).

Customers should state their needs through their Premium Support (CRM) or
Technical Account Manager (TAM Issue Tracker) accounts, or other Red Hat
representatives a version 4 "Tech Preview."  It would then be considered.

Nathan McDavit-Van Fleet wrote:
> I'm a little baffled by the Redhat installer rpm. It
> give it a list of packages to install but it just wasn't doing
> it. I have to keep trying over and over until I had everything
> installed.

Are you utilizing YUM?  YUM handles all these details.  For it to work
on Red Hat Enterprise Linux to the Red Hat Network (RHN), the system
must be subscribed to RHN.  RHN is supported via YUM plug-in.

YUM will handle all dependency resolution for you, assuming components
are available in Release 5.

Jason Frisvold wrote:  
> You may be able to find an RPM of 4.1.1 out there..  A
> quick google search shows the fc12 ones, and it might be easy
> enough to recompile the RPM on a rhel system..  I'll be doing that
> myself in the near future, I think..

Unfortunately most will build to replace the supported DHCP release
in Red Hat Enterprise Linux release 5, possibly invalidating the
system's certified state, and possibly negating some aspects of any
Service Level Agreements (SLAs).  In the best case, it would make
supporting the system more difficult, or just break some security
updates, increasing risk.

As such, one would need to manually modify the SPEC file and/or
install it relocated (to /usr/local, instead of /etc, /usr, etc...).
That way it doesn't stomp on the Red Hat version or facilities.
However, security updates would fall on the entity or entities
providing that alternative version, not Red Hat.

One might consider if a better avenue would not be to run Fedora 13
or Red Hat Enterprise Linux release 6 Beta 2 in a VM, and migrate to
Red Hat Enterprise Linux release 6 when it is released, if this newer
DHCP version needed to be utilized.

With that "disclaimer" all said, I would start with the Source RPM
package included Red Hat Enterprise Linux release 6 Beta 2:  
  $ rpm -ihv ftp://ftp.redhat.com/pub/redhat/beta/5.90Server/source/SRPMS/dhcp-4.1.1-10.el6.src.rpm  <--  install SRPM (to ~/rpmbuild/)
  $ vim ~/rpmbuild/SPEC/dhcp.spec  <--  edit SPEC file
  $ rebuild -ba ~/rpmbuild/SPEC/dhcpd.spec  <--  rebuild
  $ yum localinstall ~/rpmbuild/RPMS/(arch)/dhcp-4.1.1-10.el(rel).(arch).rpm  <--  install

YMMV (i.e., expect things to break, possible, additional dependencies,
etc...), "Danger Will Robinson!!!" when it comes to your support, etc...

[ SIDE NOTE:  This is a classic Fedora(TM) leading developments v. Red
Hat(R) trailing development argument.  If you need new features, consider
deploying Fedora, until they are in Red Hat Enterprise Linux, and then
switch to Red Hat Enterprise Linux for long-term deployment. ]

-- 
Bryan J  Smith             Professional, Technical Annoyance 
Linked Profile:           http://www.linkedin.com/in/bjsmith 
------------------------------------------------------------ 
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