How to prevent nginx errors due to docker boot sequence - docker

Question

I have managed swarm using compose.yml as follows.
compose.yml
version: '3'
services:
web:
image: nginx
depends_on:
- db
- api
deploy:
replicas: 2
update_config:
parallelism: 2
delay: 10s
db:
image: mysql
environment:
MYSQL_ROOT_PASSWORD: password
MYSQL_DATABASE: main
MYSQL_USER: root
MYSQL_PASSWORD: password
deploy:
placement:
constraints: [node.role == manager]
api:
image: node
depends_on:
- db
deploy:
replicas: 2
update_config:
parallelism: 2
delay: 10s
restart_policy:
condition: on-failure
nginx.conf
upstream test-web {
server web:5000 fail_timeout=5s max_fails=5;
}
proxy_pass http://test-web;
The problem that I am having is that the starting order of docker containers will be random as follows.
Unexpected boot results
docker stack deploy --compose-file compose.yml blue --with-registry-auth
Creating network main_default
Creating service
Creating service main_web
Creating service main_db
Creating service main_api
Startup results as expected
docker stack deploy --compose-file compose.yml blue --with-registry-auth
Creating network main_default
Creating service
Creating service main_db
Creating service main_api
Creating service main_web
If the web container is launched earlier than the api container, nginx encounters an error that api host is not found because web container does not know that api container exists.
So I'm investigating ways to improve this problem from the following layers.
nginx
is there an option to retry with nginx option even if api domain could not be found?
docker-compose
is there a method to reliably fix the start order of containers other than links and depends_on?
supervisor
To start the process in docker I am running via supervisor now.
is there a way to retry and start nginx among supervisor option even if an api container is not found and an error occurs?
Thnak you for reading my question.