A colleague here is trying to build a 64-bit network boot image, but he
is creating it on a 32-bit host.  We can't figure out how to make yum
grab the 64-bit packages in this case. 
Any idea what we can do to force yum to grab 64-bit packages while
running on a 32-bit host?  We tried specifying the x86_64 architecture
as in the following example, but this doesn't work:

[root@hlt-test yumtest]# uname -m
i686
[root@hlt-test yumtest]# yum --downloadonly --downloaddir=/tmp/yumtest
install agg.x86_64
Loaded plugins: downloadonly, kernel-module
Setting up Install Process
Parsing package install arguments
No package agg.x86_64 available.
Nothing to do


The opposite situation works fine - I tried a 64-bit host and was able
to get the 32-bit packages as expected:

[root@fc4 yumtest]# uname -m
x86_64
[root@fc4 yumtest]# yum --disablerepo=epel --downloadonly
--downloaddir=/tmp/yumtest install agg.i386
Loaded plugins: downloadonly, kernel-module, keys
Setting up Install Process
Parsing package install arguments
Resolving Dependencies
--> Running transaction check
---> Package agg.i386 0:2.4-2.1 set to be updated
--> Processing Dependency: libSDL-1.2.so.0 for package: agg
--> Running transaction check
---> Package SDL.i386 0:1.2.10-8.el5 set to be updated
--> Finished Dependency Resolution
Beginning Kernel Module Plugin
Finished Kernel Module Plugin

Dependencies Resolved

 ===========================================================================================================================================
 Package                      Arch                         
Version                                 
Repository                        Size
 ===========================================================================================================================================
Installing:
 agg                          i386                         
2.4-2.1                                 
sl-base                          139 k
Installing for dependencies:
 SDL                          i386                         
1.2.10-8.el5                            
sl-base                          233 k

Transaction Summary
 ===========================================================================================================================================
Install      2 Package(s)
Update       0 Package(s)
Remove       0 Package(s)

Total size: 372 k
Is this ok [y/N]: y
Downloading Packages:


exiting because --downloadonly specified

----


Any ideas?

Thanks,

-Wayne