How to deploy Kong to docker swarm?

As there is no answer here I will leave some things that I learned recently even if it's not related to Kong. This question seems more related to container startup order than to Kong itself.

The depends_on option is ignored when deploying a stack in swarm mode with a version 3 Compose file.

I tried to deploy Traefik with configuration stored in Consul to Swarm.The scenario was:

• I had to deploy first my storage backend: consul
• Then deploy an instance of traefik which would upload config to consul: traefik_init
• And finally I could deploy all traefik instances with consul backend: traefik

I was not able to deploy consul, traefik_init and traefik in the same stack.Since I was alreay using Ansible I created a playbook doing the following

• deploy consul stack
• wait for all consul nodes to be synced
• start traefik_init as a service with only 1 replica
• wait for the configuration to be stored in consul
• deploy traefik stack.

I could have deployed all services in same stack if I chose to override both ENTRYPOINT and CMD of containers to use a script that wait for needed services to be up and then execute command at startup.

If I were not using Ansible already I would definitely have gone that way.

You can take a look at wait-for-it (pure bash script to test and wait on the availability of a TCP host and port) or wait-for(script to wait for another service to become available) for examples.

You can also find an example at https://docs.docker.com/compose/startup-order/