A few machines, one set of services.
Swarm is built into every Docker Engine. You no longer say "start this container there", but "I want three of this service", and the swarm decides where they run and starts them again when a node falls away. The app shows what is in a swarm, runs it, and helps you start one on your own servers — with a question first wherever one click reaches more than one machine.
Fig. — The Swarm page opens on the Overview: the manager, the nodes, the join tokens behind a menu, and autolock as a switch.
New to swarms?Read the comic: a restaurant, a head chef, and a cook who goes home at nine →What you can do
In a swarm, and as what
Every machine card says whether it is a manager, a worker or neither, and machines in the same swarm share a mark. A locked swarm shows up in the status bar.
Services per stack
How many run of how many should, where each task runs and why one stopped. The logs of all tasks of a service together, in one view.
Scale, roll out, roll back
Scale a service, roll out a new image with the rolling update from its spec, roll it back or out again. Adjust environment, ports, limits, restart policy and placement, or create a small one.
Stacks from their compose file
Deploy a stack from its file, see where it differs from that file, deploy it again with what changes shown first, or remove it. Volumes stay.
Nodes
Role, state, leader and labels. Drain one after seeing which tasks move and what has nowhere to go; pause, activate, promote or demote with a warning about the quorum.
Secrets and configs
Create one from text or a file, see which services use it, and replace it in one step that switches every service over. What a secret holds goes straight to the swarm and is never kept or shown.
Start one, or join one
Start a swarm on the machine you are on, or join one through a manager that is also in the app — it fetches the token itself. Pasting a token works too.
The overview first
On a manager the page opens on the Overview: the leader, the nodes, and the join tokens, each with a menu to show, copy, copy the join command or renew. Autolock is a switch that asks first; its key is shown once. The last manager only leaves after you type the machine’s name.
A task is not a container
On Containers, a container that belongs to a service points to it, and asks before you stop what the swarm would only replace.
Events and notices
Services, nodes, secrets and configs on the Events page. A notice when a node goes down, the leader changes, an update is rolled back or stalls, or a service stays below its count — and one per service for tasks that keep failing.
A swarm chapter in the checkup
One manager or an even number, ports open to every node through ingress, services without a restart policy or health check, nodes drained for days, secrets nobody uses.
"scale web to 3"
Ctrl+K knows services, stacks and nodes. Type "scale web to 3" or "drain node2", in any of the five languages.
Your own servers
The address is the hard part, so the app says which one.
Under WSL the address of the distro cannot be reached from other machines without mirrored networking, and under Docker Desktop neither. The app looks at where the engine runs, suggests the address others can reach — Wi-Fi and Ethernet before a VPN — and lists the ports a firewall has to let through: 2377, 7946 and 4789.
One click, more than one machine
The question says what moves before anything does.
Draining a node moves everything on it; the last manager leaving takes the whole swarm with it. Those buttons first say what will happen, with names and numbers, and the most dangerous ones ask you to type the name of the machine.
Nothing new to install
Swarm mode is part of the engine you already run.
No agent and no extra daemon. The app talks to a manager the way the docker CLI does, and stacks go through docker stack deploy on the machine you are on, whatever the CLI itself points at.
All features