A lot of companies are unsure which solution to choose and many may not be aware of Docker Swarm as an alternative to Kubernetes.  One thing that many Sysadmins find is that Docker Swarm is simply easier, quicker to setup and maintain by far than Kubernetes. 

See for yourself with this Docker Tutorial which includes Docker Swarm.

See the difference with one of our favorite and most efficient Kubernetes implementations.

One striking feature is that if we compare deploying the same container by setting up a 3 node Docker Swarm or Kubernetes, it is MUCH quicker to get the same application going in Kubernetes.

Administration and Expertise

• Docker Swarm: Given its simplicity and integration with Docker, the administration overhead for Docker Swarm is significantly lower than Kubernetes. It requires less specialized knowledge, making it easier for teams already familiar with Docker to manage a Swarm environment. This translates into lower costs related to training and hiring specialized personnel. Smaller teams can effectively manage Swarm clusters without the need for dedicated DevOps roles focused solely on cluster management.

• Kubernetes: Kubernetes' complexity and rich feature set necessitate a higher level of expertise and more administration time. Managing a Kubernetes cluster involves understanding various components like pods, services, deployments, and more, which has a steeper learning curve. Organizations often need to invest in specialized training for their teams or hire experienced Kubernetes administrators. This can significantly increase the manpower cost. Additionally, the ongoing management and optimization of Kubernetes clusters require more dedicated resources, potentially leading to higher costs in terms of both manpower and administration time.

Operational Costs

• Docker Swarm: The operational costs of running Docker Swarm are generally lower, not just in terms of the computing resources required but also considering the manpower needed for its administration. Its lightweight nature means that it can run on less powerful hardware or cloud instances, further reducing costs.

• Kubernetes: Kubernetes can be more resource-intensive, requiring more robust hardware or higher-tier cloud services to accommodate its operational demands. Additionally, the cost of employing skilled Kubernetes operators or DevOps engineers can be substantial. While Kubernetes can optimize resource utilization and cost through features like auto-scaling, the initial setup, ongoing management, and optimization require continuous effort and expertise.

Total Cost of Ownership (TCO)

The Total Cost of Ownership for Kubernetes vs. Docker Swarm extends beyond just the immediate resource and manpower costs. It includes training, the complexity of operations, the scale of deployment, and the potential need for additional tools or services to manage and monitor the environment.

• Docker Swarm: Offers a lower TCO for smaller to medium-sized deployments or for teams with limited DevOps resources. Its ease of use and lower resource requirements make it a cost-effective solution for many scenarios, especially when operational simplicity and lower manpower costs are prioritized.

• Kubernetes: While the TCO can be higher, especially with larger deployments requiring skilled personnel, Kubernetes' scalability and efficiency can, in the long run, offer cost savings for complex, large-scale applications and environments that benefit from its advanced features. The investment in Kubernetes can lead to better resource utilization, higher availability, and more dynamic scaling, potentially offsetting the higher initial costs over time.

Ease of Setup and Use

• Docker Swarm: It is significantly easier to set up and configure Docker Swarm compared to Kubernetes. This is because Docker Swarm is tightly integrated into the Docker ecosystem. Setting up a Swarm cluster can be as simple as initiating a few Docker commands. This simplicity extends to its management and operation, making it more accessible for beginners or teams with smaller-scale deployments.

• Kubernetes: Setting up a Kubernetes cluster is more complex and involves a steeper learning curve. Kubernetes offers more features and flexibility, which comes at the cost of increased complexity in setup and management. However, tools like Minikube or managed Kubernetes services (e.g., EKS, AKS, GKE) can help alleviate some of the setup difficulties.

Scalability

• Docker Swarm: Offers fast and straightforward scalability. Swarm is designed to be efficient in scaling up and down in response to demand. However, it might not handle extremely large clusters as efficiently as Kubernetes.

• Kubernetes: Known for its robust scalability features. It can manage much larger clusters efficiently and provides more options for high availability and load balancing. Kubernetes is the go-to for enterprises needing to scale their applications massively.

Features and Flexibility

• Docker Swarm: Provides a simpler model for deploying applications, with a focus on ease of use and integration with Docker containers. It lacks some of the advanced features found in Kubernetes but covers the basic needs of container orchestration well.

• Kubernetes: Offers a rich set of features including but not limited to auto-scaling, self-healing, service discovery, and load balancing. Its extensibility and flexibility make it suitable for complex applications and workflows.

Resource Requirements

• Docker Swarm: Requires fewer resources compared to Kubernetes, making it a more economical option for smaller operations or where resources are limited. Its lightweight nature means it can run effectively on smaller setups.

• Kubernetes: Due to its extensive feature set and the complexity of managing large clusters, Kubernetes generally requires more resources (CPU, memory) to run effectively. This can be a consideration for organizations with limited resources.

Community and Ecosystem

• Docker Swarm: While Docker Swarm enjoys support from the Docker community, its ecosystem is not as vast or active as Kubernetes'. This can affect the availability of third-party tools and integrations.

• Kubernetes: Boasts a large and active community. The ecosystem around Kubernetes is rich with third-party tools, services, and integrations, making it easier to find support and resources for extending Kubernetes capabilities.

Use Cases

• Docker Swarm: Ideal for small to medium-sized deployments, startups, or for those who prefer simplicity and are already invested in the Docker ecosystem. It's also well-suited for applications that do not require the complex orchestration features offered by Kubernetes.

• Kubernetes: Suited for larger, more complex applications and enterprises requiring high scalability, extensive automation, and advanced deployment strategies. It's the choice for multi-cloud and hybrid-cloud environments due to its flexibility and wide industry support.

Disaster Recovery Implications

1. Faster Initial Recovery: Given that Docker Swarm allows for quicker deployment, in the event of a disaster, restoring services to operational status can be achieved more rapidly. This speed is beneficial for minimizing downtime and reducing the impact on business operations.

2. Ease of Management: Docker Swarm's simplicity also means it's easier to manage in stressful situations, such as during disaster recovery. Fewer complexities reduce the risk of errors during the recovery process, making it more straightforward to execute recovery plans.

3. Scalability Concerns: While Docker Swarm offers speed and simplicity, it's important to note that Kubernetes provides more advanced features for handling large-scale, complex applications. In disaster recovery, this might mean Kubernetes can offer better long-term scalability and resilience options, despite its slower initial setup time. However, for many applications, Docker Swarm's capabilities are more than adequate, especially when rapid recovery is a priority.

4. Automation and Orchestration: Kubernetes excels in automation and orchestration, which can be advantageous in automatically managing application deployment and recovery across a large number of nodes. Docker Swarm, while simpler, may require more manual intervention in complex scenarios. However, for many scenarios, the speed and ease of use of Docker Swarm can outweigh these benefits, especially in environments where the application architecture aligns well with Swarm's model.

Can Docker Swarm Be Used at Scale?

Large Deployments Using Docker Swarm

Companies have chosen Docker Swarm for its lightweight nature and ease of use, especially when their infrastructure does not demand the extensive scalability and complex orchestration features provided by Kubernetes. Companies in sectors like technology, finance, and e-commerce have utilized Docker Swarm for hosting web applications, microservices, and internal tools, appreciating its straightforward scaling and deployment mechanisms.

Limitations and Scalability

• Nodes: Docker Swarm is designed to be scalable and handle a large number of nodes efficiently. Officially, Docker has tested and supports Swarm clusters up to 2,000 nodes and 100,000 containers with no significant impact on performance.   Keep in mind this was back in 2016 and there are no known or listed limitations in how many nodes Docker can have.  These numbers serve as a benchmark for Docker Swarm's scalability, indicating its capability to support large-scale deployments. However, the practical limit can depend on the specific architecture, network setup, and the workload of the applications being run. https://etoews.github.io/blog/2016/08/05/joining-100-nodes-to-a-docker-swarm/

• Practical Considerations: While Docker Swarm can technically support thousands of nodes, the practical scalability limit for a cluster might be influenced by factors like network latency, cluster management overhead, and the complexity of deployed services. For most use cases, Docker Swarm offers sufficient scalability. It's also worth noting that very large-scale applications that require intricate orchestration, advanced scheduling, or extensive automation might reach a point where Kubernetes offers advantages due to its richer feature set and ecosystem.

• Examples of large deployments of Docker Swarm: There are reports of loads runnning 100,000 containers and more than 10,000 nodes.  There is no known limit that we've seen, so it is untrue that Docker Swarm cannot be deployed at scale.

• More than 100 Mirantis customers utilize Swarm for production workloads, including GlaxoSmithKline, MetLife, Royal Bank of Canada, and S&P Global. This translates to more than 10,000 nodes spread across approximately 1,000 clusters, supporting over 100,000 containers orchestrated by Swarm.

Conclusion

Choosing between Docker Swarm and Kubernetes depends on your project's size, complexity, and specific requirements. Docker Swarm is a great choice for those valuing simplicity, ease of setup, and lower resource requirements. Kubernetes, on the other hand, is suited for those needing a highly scalable, feature-rich platform capable of managing complex applications and workflows. Each tool has its strengths, and the decision should align with your technical needs, team's expertise, and long-term strategy.  The easiest answer to the question is that if you don't need the extra features that Kubernetes provides, then you cannot go wrong with Docker Swarm.

docker, swarm, vs, kubernetes, guidea, unsure, administration, expertise, simplicity, integration, overhead, significantly, requires, specialized, teams, translates, hiring, effectively, clusters, dedicated, devops, roles, solely, cluster, complexity, feature, necessitate, managing, involves, various, components, pods, deployments, steeper, organizations, invest, administrators, manpower, additionally, ongoing, optimization, potentially, operational, generally, computing, lightweight, hardware, instances, reducing, resource, intensive, requiring, robust, tier, accommodate, demands, employing, skilled, operators, engineers, substantial, optimize, utilization, features, auto, scaling, initial, continuous, ownership, tco, extends, includes, operations, deployment, additional, offers, medium, sized, limited, requirements, scenarios, prioritized, larger, scalability, efficiency, savings, applications, environments, advanced, availability, dynamic, offsetting, configure, tightly, integrated, ecosystem, initiating, commands, accessible, beginners, flexibility, increased, minikube, eks, aks, gke, alleviate, difficulties, straightforward, efficient, efficiently, provides, balancing, enterprises, massively, simpler, deploying, containers, lacks, container, orchestration, extensibility, suitable, workflows, fewer, economical, setups, extensive, cpu, consideration, enjoys, vast, active, integrations, boasts, extending, capabilities, ideal, startups, invested, suited, automation, strategies, multi, hybrid, infrastructure, provided, sectors, finance, commerce, utilized, hosting, microservices, appreciating, mechanisms, limitations, nodes, scalable, supports, significant, benchmark, indicating, capability, architecture, workload, considerations, influenced, factors, latency, deployed, sufficient, noting, intricate, scheduling, advantages, richer, examples, loads, runnning, ve, untrue, mirantis, utilize, workloads, glaxosmithkline, metlife, global, approximately, supporting, orchestrated, choosing, valuing, platform, strengths, align, technical,

Latest Articles