can someone think of a reason why a jar running on a docker image running in ecs would respond fine ...

# server

[Fred Friis]

can someone think of a reason why a jar running on a docker image running in ecs would respond fine when curled

curl --request GET \
    --location '<https://my.service.elb/actuator/prometheus>' \
    --header 'Content-Type: application/json' \
    --header 'Authorization: Basic BLABLA' \
    --header 'Host: <http://ws-preprod-api.eng.mycompany.com|ws-preprod-api.eng.mycompany.com>' \
    --insecure

# HELP CalculateTaxEndpoint_invoke90_count_total
# TYPE CalculateTaxEndpoint_invoke90_count_total counter
CalculateTaxEndpoint_invoke90_count_total{calc="invoke90",} 0.0

but when a sidecar running alongside it in ecs makes requests to it it doesn't work

<http://127.0.1:9001/actuator/prometheus>

Failed to establish a new connection: Connection refused

we're pretty sure the port and protocol are correct, because when i run the target docker image locally likewise I can

curl <http://127.0.0.1:9001/actuator/prometheus> //works fine

[Emil Kantis]

It might not be using 127.0.0.1 as loopback. Try 0.0.0.0

[Miroljub Enjaković [EpicGuy4000]]

also, 127.0.1 is not a valid ip, 127.0.0.1 is however

[Fred Friis]

@Emil Kantis woot! will do

@Miroljub Enjaković [EpicGuy4000] great spot, thanks! I've confirmed however that was just a typo when I wrote the message 🙃 and we were always dealing with 127.0.0.1 in the code and configs

[Emil Kantis]

Try localhost also 🙂

[Fred Friis]

yeah good call localhost we started with and it likewise didn't work 😕 fingers crossed for 0.0.0.0, if it works I'll be both surprised (never seen that before!) and extremely grateful!!

[Emil Kantis]

Does ECS run sidecars in bridged network mode? Otherwise you might need to refer to your main container by name? 🤔

[Miroljub Enjaković [EpicGuy4000]]

A note from the docker documentation: https://docs.docker.com/desktop/networking/#i-want-to-connect-from-a-container-to-a-service-on-the-host
If accessing host from within container, use host.docker.internal as DNS name

[Miroljub Enjaković [EpicGuy4000]]

But for ECS it might be different, if you find it is can you please share? 🙂