Currently still using Docker Swarm, i wish it was more popular, because it's oftentimes the logical next step when moving from running Docker containers manually or Docker Compose locally. It is pretty simple to use (especially with Portainer), not as resource intensive as most Kubernetes distros and the Compose format now matches what you'd run locally (with extra options, e.g. on which host to run things) vs the spammy format of Kubernetes manifests or even Helm charts.
Though it's essentially inevitable that Swarm will be abandoned some day, so being able to migrate over to either Hashicorp Nomad or some Kubernetes distro is probably paramount, which is when tools like Kompose come in, when that's finally necessary. The problem of what cluster to run on still remains for all of the folks who are stuck with on-prem deployments, since most orgs can't pay for a team to manage a cluster or for bunches of hardware resources to run the full Kubernetes.
In that regard, the best option that i've found so far is either K3s with Portainer, or K3s with Rancher (RKE and probably RKE2 will still be somewhat heavyweight).
Agreed. I never really got hooked on Docker itself, but Swarm is well-scoped and easy to use without sacrificing too much; I'd argue the vast majority of k8s users would be better off with something simpler, and Swarm fits the bill nicely. Maybe Nomad does too, but IMO Hashicorp do a really bad job of documenting the progression from a localhost test to a production setup; the docs for each of their tools can be summarised as "draw the rest of the fucking owl".
