Comment 4 for bug 2033980

so, this error message appears at exactly two locations in the neutron codebase:

"Unable to convert value in"

https://github.com/search?q=repo%3Aopenstack%2Fneutron+%22Unable+to+convert+value+in%22&type=code

1. in the "get_value_from_file" function in utils.py:

https://github.com/openstack/neutron/blob/c33805919eb89f5ea6d8b54d4142d4c829d9a2a0/neutron/agent/linux/utils.py#L250

2. in the "_get_value_from_conf_file" function in dhcp.py:

https://github.com/openstack/neutron/blob/c33805919eb89f5ea6d8b54d4142d4c829d9a2a0/neutron/agent/linux/dhcp.py#L401

the function in 1. is being called in:

https://github.com/openstack/neutron/blob/c33805919eb89f5ea6d8b54d4142d4c829d9a2a0/neutron/agent/linux/external_process.py#L154

in the function "pid" from class "ProcessManager".

This Logic was implemented in:

https://review.opendev.org/c/openstack/neutron/+/115935

Blueprint: https://blueprints.launchpad.net/openstack/?searchtext=agent-child-processes-status

the commit message reads:

"Implements ProcessMonitor in the dhcp_agent

The ProcessMonitor class will watch over spawned external processes,
taking the administrator configured action in the case of any
of the external processes die unexpectedly.

It covers both the neutron-ns-metadata-proxy for isolated metadata
and dnsmasq in the dnsmasq driver.

ProcessMonitor has been extended to allow specific pid files
for backwards-compatible dnsmasq pid file location.
"

sadly there are no other docs added in this changeset which explain the process of how to configure this
administrative action.