This article is part of the series that compare Kubernetes and Docker Swarm features.
- Kubernetes Pods, ReplicaSets, And Services Compared To Docker Swarm Stacks
- Kubernetes Deployments Compared To Docker Swarm Stacks
- Kubernetes Ingress Compared To Docker Swarm Equivalent
- Kubernetes ConfigMaps Compared To Docker Swarm Configs
- Kubernetes Secrets Compared To Docker Swarm Secrets
The mechanisms behind Kubernetes ConfigMaps and Docker Swarm configs are almost the same. At least, from the functional perspective. Both allow us to store some literal texts in scheduler’s internal data store, and both enable us to add them to containers. The syntax is equally simple and straightforward in both cases. Still, there are a few differences.
Docker Swarm’s Config is immutable. We cannot enter into a container and remove it. We cannot update it. All we can do is read it. Kubernetes will allow us to manipulate injected configuration files, only to revert changes soon after. It is acting like a cleaning lady. You can create any mess you want, she’ll clean it up. Or, maybe, that would be a butler? Not sure… Anyways, Kubernetes ConfigMap mounts are eventually immutable. Such a thing is not a big deal. We just need to understand how it works and to learn never to touch configuration files. Or, even better, we should change the default mount’s permissions to be read-only.