[{"data":1,"prerenderedAt":316},["ShallowReactive",2],{"navigation":3,"\u002Fen\u002Fblog\u002Fwhat-is-docker-swarm":4,"\u002Fen\u002Fblog\u002Fwhat-is-docker-swarm-surround":305},[],{"id":5,"title":6,"authors":7,"badge":13,"body":14,"date":293,"description":294,"extension":295,"image":296,"lastUpdated":298,"meta":299,"navigation":300,"path":301,"published":300,"seo":302,"stem":303,"tags":13,"__hash__":304},"posts\u002Fen\u002F3.blog\u002F56.what-is-docker-swarm.md","What is Docker Swarm? Container Orchestration Built In",[8],{"name":9,"to":10,"avatar":11},"Thomas Ens","\u002Fabout\u002Fthomasens",{"src":12},"\u002Fimages\u002Fblog\u002Fauthors\u002Fthomas.jpeg",null,{"type":15,"value":16,"toc":278},"minimark",[17,29,34,37,49,53,56,59,62,65,69,77,80,83,88,91,94,98,101,104,107,111,121,128,131,135,148,154,160,163,238,242,245,264,267,270],[18,19,20,21,28],"p",{},"Docker Swarm is the native clustering and orchestration solution from ",[22,23,27],"a",{"href":24,"rel":25},"https:\u002F\u002Fwww.docker.com\u002F",[26],"nofollow","Docker",". It is built directly into the Docker Engine and makes it possible to combine several Docker hosts into a single cluster without installing any separate tools. Anyone who wants to run containers on more than one server gets a solid foundation with Docker Swarm: easy to set up, built on familiar Docker tooling, and perfectly sufficient for many setups.",[30,31,33],"h2",{"id":32},"swarm-mode-whats-behind-it","Swarm Mode. What's behind it?",[18,35,36],{},"Since Docker 1.12, Swarm is no longer a separate project but a built-in operating mode of the Docker Engine, known as Swarm Mode. That means every current Docker installation can run a Swarm cluster without any additional packages or external dependencies.",[18,38,39,40,44,45,48],{},"The conceptual difference between ",[41,42,43],"code",{},"docker run"," or ",[41,46,47],{},"docker-compose"," and Swarm lies in the level of abstraction. Swarm does not think in terms of individual containers running on a specific host; it thinks in terms of services that are executed across the cluster as a whole. Where exactly a container ends up is decided by the scheduler.",[30,50,52],{"id":51},"manager-and-worker-nodes-at-a-glance","Manager and worker nodes at a glance",[18,54,55],{},"A Swarm cluster consists of two types of nodes:",[18,57,58],{},"Manager nodes are responsible for cluster administration. They accept API requests, distribute jobs (so-called tasks) to worker nodes, and monitor the state of the cluster. Manager nodes use the Raft consensus protocol to maintain a consistent cluster state among themselves. If one manager fails, another takes over, provided that the majority of the managers is still reachable.",[18,60,61],{},"That leads to a practical rule of thumb: anyone who wants high availability should run 3 or 5 manager nodes. With 3 managers, one may fail; with 5 managers, two may fail.",[18,63,64],{},"Worker nodes run the containers. They receive tasks from the manager and report their status back — nothing more. Worker nodes have no access to the cluster state and cannot perform management operations.",[30,66,68],{"id":67},"services-tasks-and-the-desired-state","Services, tasks, and the desired state",[18,70,71,72,76],{},"The central concept in Docker Swarm is the ",[73,74,75],"strong",{},"service",". Instead of starting a container manually, you define a service with a desired number of replicas.",[18,78,79],{},"Swarm makes sure that exactly 3 instances of the Nginx container are running at all times, distributed across the available worker nodes. If one fails, the manager detects it and starts a new task. This principle is called desired state reconciliation: Swarm continuously compares the desired state with the actual state.",[18,81,82],{},"Tasks are the smallest units in Swarm; each task corresponds to one container on a specific node. The service is the object you describe and manage; the tasks are created from it automatically.",[84,85,87],"h3",{"id":86},"rolling-updates-and-rollbacks","Rolling updates and rollbacks",[18,89,90],{},"A common problem with manual deployments: either brief downtime when swapping out the container, or complicated blue\u002Fgreen setups. Swarm solves this with built-in rolling updates.",[18,92,93],{},"Swarm remembers the previous state of the service and can restore it without any manual intervention.",[30,95,97],{"id":96},"overlay-networks-and-service-discovery","Overlay networks and service discovery",[18,99,100],{},"When several services on different nodes need to communicate — for instance, a backend service talking to a database — you need a network that bridges host boundaries. Docker Swarm provides overlay networks for exactly that.",[18,102,103],{},"Services that are assigned to the same overlay network can reach each other by their service name, regardless of which node the containers are currently running on. The integrated DNS resolver handles service discovery automatically.",[18,105,106],{},"That removes the need to manually manage IP addresses and makes service-to-service communication within the cluster transparent.",[30,108,110],{"id":109},"docker-stack-and-compose-integration","Docker Stack and Compose integration",[18,112,113,114,116,117,120],{},"Teams that already work with ",[41,115,47],{}," can bring their existing knowledge straight into Swarm. With ",[41,118,119],{},"docker stack deploy",", Compose files in v3 format can be deployed directly into Swarm.",[18,122,123,124,127],{},"A stack is essentially a group of services that are deployed and managed together. The Compose file remains largely unchanged; only Swarm-specific settings such as replica count or update configuration are added under the ",[41,125,126],{},"deploy"," key:",[18,129,130],{},"This path makes the entry into Swarm especially low-barrier for Compose users.",[30,132,134],{"id":133},"docker-swarm-vs-kubernetes-when-to-use-which","Docker Swarm vs. Kubernetes. When to use which?",[18,136,137,138,142,143,147],{},"The ",[22,139,141],{"href":140},"\u002Fen\u002Fblog\u002Fkubernetes-vs-docker-swarm","comparison between Docker Swarm and Kubernetes"," comes up regularly, and the answer is less binary than is often claimed. For the wider ",[22,144,146],{"href":145},"\u002Fen\u002Fblog\u002Fdocker-vs-kubernetes","decision between Docker, Compose, Swarm, and Kubernetes",", see our full comparison.",[18,149,150,153],{},[73,151,152],{},"Kubernetes"," has a significantly larger feature set: native Horizontal Pod Autoscaling, detailed RBAC, Custom Resource Definitions, a huge ecosystem of operators and tools. In return, the entry barrier is higher, operations are more demanding, and the learning curve is steeper.",[18,155,156,159],{},[73,157,158],{},"Docker Swarm"," is conceptually simpler, faster to set up, and sufficient for many use cases. Anyone without a dedicated DevOps team or who does not need Kubernetes often fares more pragmatically with Swarm.",[18,161,162],{},"Key differences at a glance:",[164,165,166,179],"table",{},[167,168,169],"thead",{},[170,171,172,175,177],"tr",{},[173,174],"th",{},[173,176,158],{},[173,178,152],{},[180,181,182,194,205,216,227],"tbody",{},[170,183,184,188,191],{},[185,186,187],"td",{},"Getting started",[185,189,190],{},"Simple",[185,192,193],{},"Complex",[170,195,196,199,202],{},[185,197,198],{},"Auto-scaling",[185,200,201],{},"Not native",[185,203,204],{},"Yes",[170,206,207,210,213],{},[185,208,209],{},"RBAC",[185,211,212],{},"Limited",[185,214,215],{},"Full",[170,217,218,221,224],{},[185,219,220],{},"Ecosystem",[185,222,223],{},"Small",[185,225,226],{},"Large",[170,228,229,232,235],{},[185,230,231],{},"Resource footprint",[185,233,234],{},"Low",[185,236,237],{},"Higher",[84,239,241],{"id":240},"when-swarm-is-the-right-choice","When Swarm is the right choice",[18,243,244],{},"Swarm makes sense when:",[246,247,248,255,258,261],"ul",{},[249,250,251,252],"li",{},"The team knows Docker but has not yet adopted ",[22,253,152],{"href":254},"\u002Fen\u002Fblog\u002Fwhat-is-kubernetes",[249,256,257],{},"The infrastructure is manageable and no automatic scaling is needed",[249,259,260],{},"Bare-metal servers or small VMs are used without cloud-managed Kubernetes",[249,262,263],{},"Operational complexity should deliberately be kept low",[18,265,266],{},"As soon as the requirements grow — more teams, more complex network topologies, fine-grained access control, scaling automation — Swarm hits its limits.",[268,269],"hr",{},[18,271,272,273,277],{},"Docker Swarm is a solid entry point into container orchestration, without the operational overhead that Kubernetes brings with it. But anyone who realises that the requirements are growing and that a full Kubernetes setup would make sense does not have to build and operate it themselves. lowcloud offers a ",[22,274,276],{"href":275},"\u002Fen\u002Fblog\u002Fdevops-as-a-service","DevOps-as-a-Service platform"," with Kubernetes at its core that simplifies the operation of Kubernetes clusters on sovereign infrastructure — without cloud, without vendor lock-in, and with a focus on what matters: your own application.",{"title":279,"searchDepth":280,"depth":280,"links":281},"",2,[282,283,284,288,289,290],{"id":32,"depth":280,"text":33},{"id":51,"depth":280,"text":52},{"id":67,"depth":280,"text":68,"children":285},[286],{"id":86,"depth":287,"text":87},3,{"id":96,"depth":280,"text":97},{"id":109,"depth":280,"text":110},{"id":133,"depth":280,"text":134,"children":291},[292],{"id":240,"depth":287,"text":241},"2026-04-07","Docker Swarm explained: clusters, services, overlay networks, and how it compares to Kubernetes. When Swarm is the right choice for container orchestration.","md",{"src":297},"\u002Fimages\u002Fblog\u002Fwhat-is-docker-swarm.jpg","2026-04-13",{},true,"\u002Fen\u002Fblog\u002Fwhat-is-docker-swarm",{"title":6,"description":294},"en\u002F3.blog\u002F56.what-is-docker-swarm","Ucw6_O9AFjS5tnaD1aRTVJ4yodakZlrGvL8XH9W4tfA",[306,311],{"title":307,"path":308,"stem":309,"description":310,"children":-1},"MinIO Alternatives Compared: RustFS, SeaweedFS, and Garage","\u002Fen\u002Fblog\u002Fminio-alternatives","en\u002F3.blog\u002F55.minio-alternatives","Looking for a MinIO replacement? We compare RustFS, SeaweedFS, and Garage — S3-compatible, self-hosted, and license-friendly for Kubernetes production use.",{"title":312,"path":313,"stem":314,"description":315,"children":-1},"What Is a Helm Chart? The Package Manager for Kubernetes","\u002Fen\u002Fblog\u002Fwhat-is-a-helm-chart","en\u002F3.blog\u002F57.what-is-a-helm-chart","Helm charts bundle Kubernetes resources into a versioned package. How they are structured, how templating works, and when to use them.",1776079521289]