nginx: Fails to start on boot while upstream service is not yet running

When I start my personal server with a radicale service behind a nginx

reverse proxy, nginx fails to start.

The relevant part in the log:

Nov 23 16:02:56 localhost shepherd[1]: Service networking has been started.

Nov 23 16:02:56 localhost shepherd[1]: Service radicale has been started.

Nov 23 16:02:56 localhost shepherd[1]: Service ssh-daemon has been started.

Nov 23 16:02:56 localhost shepherd[1]: [nginx] nginx: [emerg] host not

found in upstream "localhost:5232" in

/gnu/store/y29zl57pprwxbcxfx593s16456kxk99y-nginx.conf:15

Nov 23 16:02:56 localhost shepherd[1]: Failed to start nginx in the

background.

The config can be found here:

```

(upstream-blocks (list

(nginx-upstream-configuration

(name "radicale")

(servers (list "localhost:5232")))))

```

I wonder whats going wrong here. Is there a way to define that nginx

service should wait until radicale service is started?

~Jonathan

nginx-configuration has a 'shepherd-requirement' parameter that can be used here

Ah thanks.

I added `(shepherd-requirement '(radicale))` to my nginx-configuration.

Sadly the issue is not fixed, the situation is the same as before.

I assume that radicale takes a fracture of a second to start. And nginx

starts faster up. See this small experiment:

$ sudo herd stop radicale

$ sudo herd start radicale; curl localhost:5232

Service radicale has been started.

curl: (7) Failed to connect to localhost port 5232 after 0 ms:

Verbindungsaufbau abgelehnt

$ sudo herd stop radicale

$ sudo herd start radicale; sleep 0.2; curl localhost:5232

Service radicale has been started.

Redirected to /.web

Jonathan Brielmaier <jonathan.brielmaier@web.de> skribis:

That looks like a bug in the radicale service: there’s no

synchronization upon startup:

It should wait for a PID file or be started as a systemd or inetd

service. That way, we’d be sure that shepherd considers it started once

it’s really listening for input. A quick grep in the source suggests it

creates a PID file somewhere.

HTH!

Ludo’.

On 27.11.22 22:14, Ludovic Courtès wrote:> That looks like a bug in the

radicale service: there’s no

I think its rather an issue with nscd, networking or some other base

service.

Changing the nginx configuration from

(servers (list "localhost:5232"))

to

(servers (list "127.0.0.1:5232"))

resolves the issue for me :)

I couldn't find any PID file on my server of radicale. But there seems

to by a .lock file: /var/lib/radicale/collections/.Radicale.lock

No idea if that would be helpful...

~Jonathan

Closing.

Workaround with using "127.0.0.1" instead of "localhost" provided.