I tried installing 2.4 again, and then I hit another error about db::seed failing, which brought me back to this thread:
And lo and behold, with just / (slash) and a tmpfs /tmp partition, it seems to work:
2021-07-19 16:34:31 [NOTICE] [root] Loading installer configuration. This will take some time.
2021-07-19 16:34:37 [NOTICE] [root] Running installer with log based terminal output at level NOTICE.
2021-07-19 16:34:37 [NOTICE] [root] Use -l to set the terminal output log level to ERROR, WARN, NOTICE, INFO, or DEBUG. See --full-help for definitions.
2021-07-19 16:39:03 [NOTICE] [configure] Starting system configuration.
2021-07-19 16:41:41 [NOTICE] [configure] 250 configuration steps out of 2022 steps complete.
2021-07-19 16:44:11 [NOTICE] [configure] 500 configuration steps out of 2022 steps complete.
2021-07-19 16:45:07 [NOTICE] [configure] 750 configuration steps out of 2025 steps complete.
2021-07-19 16:47:02 [NOTICE] [configure] 1000 configuration steps out of 2030 steps complete.
2021-07-19 16:49:21 [NOTICE] [configure] 1250 configuration steps out of 2053 steps complete.
2021-07-19 16:58:01 [NOTICE] [configure] 1500 configuration steps out of 2053 steps complete.
2021-07-19 16:59:38 [NOTICE] [configure] 1750 configuration steps out of 2053 steps complete.
2021-07-19 17:01:22 [NOTICE] [configure] 2000 configuration steps out of 2053 steps complete.
2021-07-19 17:01:49 [NOTICE] [configure] System configuration has finished.
Executing: foreman-rake upgrade:run
`/usr/share/foreman` is not writable.
Bundler will use `/tmp/bundler20210719-14406-1qcudl914406' as your home directory temporarily.
Rubocop not loaded.
=============================================
Upgrade Step 1/5: katello:correct_repositories. This may take a long while.
=============================================
Upgrade Step 2/5: katello:clean_backend_objects. This may take a long while.
0 orphaned consumer id(s) found in candlepin.
Candlepin orphaned consumers: []
=============================================
Upgrade Step 3/5: katello:upgrades:4.0:remove_ostree_puppet_content. =============================================
Upgrade Step 4/5: katello:upgrades:4.1:sync_noarch_content. =============================================
Upgrade Step 5/5: katello:upgrades:4.1:fix_invalid_pools. I, [2021-07-19T17:02:05.194548 #14406] INFO -- : Corrected 0 invalid pools
I, [2021-07-19T17:02:05.194597 #14406] INFO -- : Removed 0 orphaned pools
I can login, tomcat seems to have no issues.
[root@foreman-server ~]# foreman-maintain health check
Running ForemanMaintain::Scenario::FilteredScenario
================================================================================
Check number of fact names in database: [OK]
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Check to verify no empty CA cert requests exist: [OK]
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Check whether all services are running: [OK]
--------------------------------------------------------------------------------
Check whether all services are running using the ping call: [OK]
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I really wonder where the problem is here.