The error referenced in the BZ description is due to a missing config file for ActionCable. However, it is not the cause of the Ui worker becoming unavailable but is should be addressed by copying config/cable.yml.sample to config/cable.yml under /var/www/miq.
For the issue of the UI becoming unavailable we have determined from the logs that the single UI worker is using up all of its puma threads (there are 5 by default) servicing long running http requests. When this happens, Apache's built in load balancer considers EVM to be unresponsive it marks it as unavailable. Since there are no additional UI workers available, Apache can no longer forward requests to EVM.
To address this, a second UI worker should be added to this appliance.
Developers use `bin/update` or `bin/setup` to get cable.yml that includes
which does the thing. I am afraid we don't run `bin/update` during upgrade process.
The ensure_config_files brings in the certs/v2_key, config/cable.yml and config/database.yml
We have different means to bring the cert and db.yml in so nobody noticed we need extra productization steps for cable.yml.
Currently, the config files are not owned by any rpm. In an old-school ideal world, all these files would be owned by RPM and marked as configuration files. That way, they are not changed by update, but system knows that they are owned by the application.
This looks like it would be a 5.6 -> 5.7 upgrade issue. I'll look into it.
This is an issue when upgrading to 5.7 and also 5.8
Adding the backport flags.
To test this you need to upgrade an appliance from 5.6 up through 5.7 and 5.8.
5.7 and 5.8 deploys will have the file there on first boot because it is copied in the kickstart, but upgraded installations will have this issue.
Verified in 126.96.36.199
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
*** Bug 1435052 has been marked as a duplicate of this bug. ***