Lots of positive stuff in this thread which I won't bother repeating. Instead, I'll add a few ambivalent points:
- Today, a lot of functionality still in Docker has been upstreamed into the (Linux) kernel, so containers can be much simpler (and rootless). Docker is still carrying around some of that cruft, which is what makes it slower and heavier than Podman.
- As a devex technology, Docker/containers have been massively successful, but not as infrastructure. Containers never became secure enough to run multitenant workloads without some other form of isolation, so they ended up being redundant with KVM (or gVisor, or a similar second layer) in production a lot of the time.
That second contradiction led to lots of inefficiency. For example, on Google App Engine, for years when you ran a deploy it would create a VM just to run a single container.
- Today, a lot of functionality still in Docker has been upstreamed into the (Linux) kernel, so containers can be much simpler (and rootless). Docker is still carrying around some of that cruft, which is what makes it slower and heavier than Podman.
- As a devex technology, Docker/containers have been massively successful, but not as infrastructure. Containers never became secure enough to run multitenant workloads without some other form of isolation, so they ended up being redundant with KVM (or gVisor, or a similar second layer) in production a lot of the time.
That second contradiction led to lots of inefficiency. For example, on Google App Engine, for years when you ran a deploy it would create a VM just to run a single container.