This is a buster instance.
Exec[retry-load-new-vcl-file-frontend]: title: retry-load-new-vcl-file-frontend file: "/etc/puppet/modules/varnish/manifests/instance.pp" line: 205 resource: Exec[retry-load-new-vcl-file-frontend]
...
message: 'change from ''notrun'' to [''0''] failed: ''/usr/local/sbin/reload-vcl -n frontend -f /etc/varnish/wikimedia_upload-frontend.vcl -d 2 -a && (rm /var/tmp/reload-vcl-failed-frontend; true)'' returned 1 instead of one of [0]'