Use the status module for health checks.

Dockerfile

@@ -23,4 +23,4 @@ COPY conf.d/ /etc/nginx/conf.d/
 COPY snippets/ /etc/nginx/snippets/
 USER nginx
 RUN nginx -t
-HEALTHCHECK CMD curl --fail --verbose --user-agent 'Docker health check' http://localhost/ || exit 1
+HEALTHCHECK CMD curl --fail --verbose --user-agent 'Docker health check' --header "Host: status" http://localhost/ || exit 1