What are the benefits of using a Single-Node Docker Swarm instead of Docker Compose?

Question

What are the actual user-noticeable differences between a stack run with Docker Compose, vs that same stack run from a single host in Swarm mode?

In other words, what are the concrete benefits, if any, of using Swarm mode with only one node vs. Docker Compose?

Research

1. I have seen other SO answers trying to tackle this question, but lack the depth I am seeking (see related info in the Docs).
2. This answer seems wrong, as Compose supports deploy keys.

Answer 1

The difference between Docker compose and Swarm is that the first is a way to connect multiple containers together while the second is an orchestrator tool.

This implies that, even in a single cluster scenario, they will be different in particular in relation to the following points:

• Healthcheck: in Swarm there are periodical healthchecks and when a container fails the healthcheck repeatedly it will be killed and restarted while on docker compose you can can just set the restart policy in case the container crash
• Deploy: Swarm has options for controlling how you replace containers during an update such as rolling update that rolls back if there’s a problem, while docker compose not
• Extra features: Swarm has additional features to manage secrets and configs
• Extend the cluster: When you want to add nodes to your cluster, with Swarm you just need to add more nodes to the master node, while on docker compose you have to re-deploy it
• Compatibility: Docker and Swarm are the same daemon, so there are no issue related to versions compatibility
• Installation: with Swarm you have no need to install additional package/plugin, such as docker compose plugin or docker-compose for older versions
• Ease: Swarm only takes a single command (docker swarm init) to create a Swarm

It saves you from needing to manually install/update docker-compose on that server. Docker engine is installable and updatable via common Linux package managers (apt, yum) via https://store.docker.com but docker-compose is not.

Of course in a multiple-nodes cluster configuration you have more benefits from using an orchestration tool like Docker Swarm.