I'm serving a simple HTML page (just says "Hi") using Nginx, behind a Traefik proxy, on a virtual machine provisioned with Vagrant. Everything runs inside Docker containers managed with Docker Compose. The setup is also exposed to the internet through Cloudflare, with DDNS configured behind it.
I also have a script that sends a ping (using curl 192.168.0.3:80) to the VM every 10 minutes.
The problem is that sometimes the script reports the page as down — but only occasionally. Interestingly, the issue often gets resolved within the script itself by performing a curl request to a different application running on the same VM.
I managed to track the issue in the Traefik logs, but I’m not sure what the root cause is. The error code returned is 499.
Can you help me identify the problem?
This is my Traefik log where the problem was identified:
192.168.0.2 - - [20/Jun/2025:15:02:11 +0000] "GET / HTTP/1.1" 200 1005 "-" "-" 436 "landing-page-router@file" "http://landing-page:80" 2ms
... (truncated for brevity)
192.168.0.2 - - [20/Jun/2025:15:12:33 +0000] "GET / HTTP/1.1" 499 21 "-" "-" 439 "landing-page-router@file" "http://landing-page:80" 0ms
... (truncated for brevity)
172.70.140.250 - - [20/Jun/2025:15:12:39 +0000] "GET / HTTP/1.1" 200 1005 "-" "-" 441 "landing-page-router@file" "http://landing-page:80" 2ms
... (truncated for brevity)
192.168.0.2 - - [20/Jun/2025:15:22:39 +0000] "GET / HTTP/1.1" 200 1005 "-" "-" 445 "landing-page-router@file" "http://landing-page:80" 2ms
2025-06-20T15:22:45Z DBG github.com/traefik/traefik/v3/pkg/server/service/loadbalancer/wrr/wrr.go:207 > Service selected by WRR: c12e145b1712d76c
The full infrastructure is this:
- Vagrant 2.4.3 (Box: bento/ubuntu-24.04) | VirtualBox | Bridge mode
- Trafik 3.3.3
- Docker 28.0.4
- Host: Windows 11
- App: Nginx (serving a simple HTML)
Thanks for your help.
