net/http: timeout awaiting response headers reported with OpenShift 4 installation on OpenStack

Issue

• While deploying Red Hat OpenShift Container Platform (OCP) on 4.x on Red Hat OpenStack Platform (OSP) 13 or higher the bootstrap machine fails to pull ignition files from Glance.
• The terminal of the Bootstrap VM reports the following error:

    [  337.908844] ignition[809]: GET http://1.2.3.4:9292/v2/images/3744fbd5-b598-4293-a975-c8379aa9f8eb/file: attempt #24
    [  347.909772] ignition[809]: GET error: Get http://12.3.4:9292/v2/images/3744fbd5-b598-4293-a975-c8379aa9f8eb/file: net/http: timeout awaiting response headers

• Meanwhile, the installation output shows the following error.

INFO Waiting up to 20m0s for the Kubernetes API at https://api.example.com:6443...
DEBUG Still waiting for the Kubernetes API: Get https://api.example.com:6443/version?timeout=32s: dial tcp 1.2.3.4:6443: connect: no route to host