Creating custom package group for yum repository gives "comps file is empty/damaged"

Question

I am having trouble setting up a custom package group for my custom yum repository in RHEL7.6.

First, here are the steps I am taking to create the custom yum repository.

1. Create a directory that will contain all the RPMs and copy over the relevant ones:

   $ mkdir MyRepo
   $ cp /path/to/some/*.rpm MyRepo/
   

2. Generate metadata for the repository:

   $ cd MyRepo
   $ createrepo .
   

Now that the custom repository is made, I move onto creating the package group as follows.

3. Create a comps.xml file in MyRepo/repodata/:

   $ touch repodata/comps.xml
   

   that contains metadata of the following form:

   <comps>
   <!--  <meta> -->
   <!-- Meta information will go here eventually... -->
   <!--  </meta> -->
     <group>
       <id>myrepo</id>
       <name>MyRepo</name>
       <default>true</default>
       <description>My custom repository</description>
       <uservisible>true</uservisible>
       <packagelist>
         <packagereq type="mandatory">octave</packagereq>
         <packagereq type="mandatory">octave-devel</packagereq>
         etc...
       </packagelist>
     </group>
   </comps>
   

4. I then update the metadata previously created to account for the group data:

   createrepo -g repodata/comps.xml .
   

5. Finally I create myrepo.repo to the /etc/yum.repos.d/ directory and put the following in it:

   [myrepo]
   name=MyRepo
   baseurl=file:///path/to/MyRepo
   enabled=1
   

Once all that is complete I yum clean all which works without complaining. But then when I go to test things via yum --noplugins groupinfo MyRepo things go badly. I get the following error:

There is no installed groups file.
Maybe run: yum groups mark convert (see man yum)
Failed to add groups file for repository: MyRepo - comps file is empty/damaged
Warning: group/environment MyRepo does not exist.

My comps file is not empty and its hash matches what is found in repodata/repomd.xml. I am pretty lost as to how to go about debugging this. What am I doing wrong? Would a mistyped package name cause this big of an error?

Thank you in advance for your help.

Answer 1

I got the same messages, "here is no installed groups file.", and "Failed to add groups file for repository: base - comps file is empty/damaged".

I was working on a default install from the official repository.

It turned out to be a cache problem.

sudo yum rm -rf /var/cache/yum

cleared it all up