Getting this?

Error populating transaction after 10 anaconda retries: failure: perl-HTTP-Tiny-0.033-3.el7.noarch.rpm from anaconda: [Errno 256] No more mirrors to try.

from the anaconda installer after rolling a custom ISO?

/tmp/yum.repos.d/anaconda.repo
[anaconda]
name=anaconda
enabled=1
baseurl=file:///run/install/repo/

Checking the primary.gz generated file list, the Packages/ path is included in the file path, but not our newly created primary.gz : 

[root@zeus01 repodata-backup]# zcat 16890efb08ba2667b3cfd83c4d234d5fabea890e6ed2ade4d4d7adec9670a9a5-primary.xml.gz|grep -Ei "Packages/"|head
  <location href="Packages/GeoIP-1.5.0-14.el7.x86_64.rpm"/>
  <location href="Packages/ModemManager-glib-1.6.10-3.el7_6.x86_64.rpm"/>
  <location href="Packages/NetworkManager-1.18.0-5.el7.x86_64.rpm"/>
  <location href="Packages/NetworkManager-adsl-1.18.0-5.el7.x86_64.rpm"/>
  <location href="Packages/NetworkManager-bluetooth-1.18.0-5.el7.x86_64.rpm"/>
  <location href="Packages/NetworkManager-glib-1.18.0-5.el7.x86_64.rpm"/>
  <location href="Packages/NetworkManager-libnm-1.18.0-5.el7.x86_64.rpm"/>
  <location href="Packages/NetworkManager-team-1.18.0-5.el7.x86_64.rpm"/>
  <location href="Packages/NetworkManager-tui-1.18.0-5.el7.x86_64.rpm"/>
  <location href="Packages/NetworkManager-wifi-1.18.0-5.el7.x86_64.rpm"/>
[root@zeus01 repodata-backup]# ls -altri 16890efb08ba2667b3cfd83c4d234d5fabea890e6ed2ade4d4d7adec9670a9a5-primary.xml.gz
806777 -rw-rw-r–. 1 root root 406843 Sep 11  2019 16890efb08ba2667b3cfd83c4d234d5fabea890e6ed2ade4d4d7adec9670a9a5-primary.xml.gz
[root@zeus01 repodata-backup]# zcat ac3a24e2e118c3a3f04d3a3b008c7d8859ee4d39327a542dcf6f46a17604e957-primary.xml.gz|grep -Ei "Packages/"|head
[root@zeus01 repodata-backup]# ls -altrid ac3a24e2e118c3a3f04d3a3b008c7d8859ee4d39327a542dcf6f46a17604e957-primary.xml.gz
884923 -rw-r–r–. 1 root root 410764 Mar 26 00:35 ac3a24e2e118c3a3f04d3a3b008c7d8859ee4d39327a542dcf6f46a17604e957-primary.xml.gz
[root@zeus01 repodata-backup]#

What was being ran is:

[root@zeus01 working]# createrepo -dpo . Packages/ -g /zeus-images/working/repodata/521f322f05f9802f2438d8bb7d97558c64ff3ff74c03322d77787ade9152d8bb-c7-x86_64-comps.xml
[root@zeus01 working]# pwd
/zeus-images/working
[root@zeus01 working]#

To include the package path Packages/, generate the repo using this command and specify the root path ( / ) of the DVD / ISO files instead of Packages/ :

[root@zeus01 working]# createrepo -dpo . ./ -g /zeus-images/working/repodata/521f322f05f9802f2438d8bb7d97558c64ff3ff74c03322d77787ade9152d8bb-c7-x86_64-comps.xml             Spawning worker 0 with 236 pkgs
Spawning worker 1 with 236 pkgs
Spawning worker 2 with 236 pkgs
Spawning worker 3 with 235 pkgs
Spawning worker 4 with 235 pkgs
Spawning worker 5 with 235 pkgs
Workers Finished
Saving Primary metadata
Saving file lists metadata
Saving other metadata
Generating sqlite DBs
Sqlite DBs complete
[root@zeus01 working]# ls -altri
total 176
136726261 -rw-rw-r–. 1 root     root      1690 Dec  9  2015 RPM-GPG-KEY-CentOS-Testing-7
136726260 -rw-rw-r–. 1 root     root      1690 Dec  9  2015 RPM-GPG-KEY-CentOS-7
136726257 -rw-rw-r–. 1 root     root     18009 Dec  9  2015 GPL
136726256 -rw-rw-r–. 1 root     root       227 Aug 30  2017 EULA
136726253 -rw-r–r–. 1 root     root        29 Sep  6  2019 .discinfo
   806768 drwxr-xr-x. 2 root     root        41 Sep  6  2019 LiveOS
202843815 drwxr-xr-x. 3 root     root        33 Sep  6  2019 EFI
136726254 -rw-r–r–. 1 root     root       354 Sep  6  2019 .treeinfo
136726252 drwxr-xr-x. 3 root     root        54 Sep  9  2019 images
136726255 -rw-rw-r–. 1 root     root        14 Sep  9  2019 CentOS_BuildTag
136726262 -r–r–r–. 1 root     root      3101 Dec  1 17:11 TRANS.TBL
213637698 drwxr-xr-x. 2 root     root      4096 Mar 30 01:26 repodata-jic
 68834653 drwxrwxr-x. 2 root     root     77824 Mar 30 01:38 Packages
202843816 drwxr-xr-x. 2 root     root      4096 Mar 30 09:26 isolinux
136726269 drwxr-xr-x. 6 zeusadmin zeusadmin  4096 Apr  4 10:54 ..
135668264 -rw——-. 1 root     root      1050 Apr  4 11:09 ks.cfg
135668262 drwxr-xr-x. 2 root     root      4096 Apr  4 16:47 repodata
136726251 drwxr-xr-x. 9 root     root      4096 Apr  4 16:47 .
[root@zeus01 working]#
[root@zeus01 repodata]# pwd
/zeus-images/working/repodata
[root@zeus01 repodata]#

Now create the ISO:

[root@zeus01 working]# mkisofs -o ../CentOS-7-x86_64-Minimal-1908-Kickstart-Context-V24.iso -untranslated-filenames -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -V "CentOS 7 x86_64" -R -J -v -T .
Warning: creating filesystem that does not conform to ISO-9660.
I: -input-charset not specified, using utf-8 (detected in locale settings)

Or using genisoimage command:

[root@one01 working]# genisoimage -untranslated-filenames -volid 'CentOS 7 x86_64' -J -joliet-long -rational-rock -translation-table -input-charset utf-8 -x  ./lost+found -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e images/efiboot.img  -no-emul-boot -o ../CentOS-7-x86_64-Minimal-1908-Kickstart-Context-GV23.iso -R -v -T .
Warning: creating filesystem that does not conform to ISO-9660.
genisoimage 1.1.11 (Linux)

Try booting using the image.  Your RPM packages should now be found. 

Thx,
DN