Comment 4 for bug 1907657

tripleo_image_serve role in tripleo-ansible prepares apache config as:
http://storage.bhs.cloud.ovh.net/v1/AUTH_dcaab5e32b234d56b626f72581e3644c/zuul_opendev_logs_177/764255/4/gate/tripleo-ci-centos-8-containers-multinode/1773ef8/logs/undercloud/etc/httpd/conf.d/image-serve.conf

 <LocationMatch "^/v2/.*/.*/blobs/sha256:.*$">
        SetEnvIf Request_URI "sha256:(.*)$" digest=sha256:$1
        Header set Docker-Content-Digest "%{digest}e"
        Header set ETag "%{digest}e"
        Header set Cache-Control "max-age=31536000"
        Header set Content-Type "application/octet-stream"
    </LocationMatch>

but URL in logs doesn't match pattern:

- LocationMatch "^/v2/.*/.*/blobs/sha256:.*$"
- POST /v2/tripleomaster/openstack-keystone/blobs/uploads/

That's why 404 errors.
But later the connection just fails:

 Retrying (Retry(total=7, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x7fa1643f5b38>: Failed to establish a new connection: [Errno 113] No route to host',)': /v2/