Docker Swarm | Quick Introduction and Basics

Описание

Swarm is native clustering for the Docker. In the context of swarm , a cluster is a pool of Docker hosts that acts as a bit like a single large docker host. You can also run swarm services and standalone containers on the same Docker instances.

Features of Swarm
- Swarm setup is very quick and easy, no separate infrastructure requirements and Swarm ships as standard Docker image.
- Swarm implements most of the Docker API endpoints, which means tools build on it can work out of the box.
- Swarm support Affinity definition/configuration , which means docker swarm launch a container only a docker host that does not already have the same container already running on.
- Swarm supports high availability, we can join multiple manager nodes to the cluster, so that if one manager node fails, another can automatically take its place without impact to the cluster.
- Swarm support scaling , for each service you can declare the number of tasks you want to run. When you scale up or down, the swarm manager automatically adapts by adding or removing tasks to maintain the desired state.
- Swarm handles desired state reconciliation very well, manager node constantly monitors the cluster state and reconciles any differences between the actual state and your expressed desired state
- Swarm supports network overlays. The swarm manager automatically assigns addresses to the containers on the overlay network when it initializes or updates the application.
- Swarm is secure by default. Each node in the swarm enforces TLS mutual authentication and encryption to secure communications between itself and all other nodes.
- Rolling updates: At rollout time you can apply service updates to nodes incrementally.