Having trouble deciding whether Kubernetes, Mesos, or Docker is the best container orchestration platform for your project? Then this article is for you.
Choosing the right container orchestration tool is definitely a big decision. DevOps Engineers will have to invest a considerable amount of time to design and test CI/CD pipelines adapted to the chosen platform, not to mention the cumbersome process of migrating containers, establishing access control policies, as well as the countless little details involved in configuring container orchestration properly.
Moreover, since each platform has its own strengths and weaknesses, the selection process itself is often a daunting task.
The objective of this article is making the process easier for DevOps engineers, Sysadmins, and IT staff by narrowing the selection to three of the most versatile opensource orchestration platforms currently available in the market, Kubernetes, Apache Mesos, and Docker Swarm.
The containerization era, and the rise of container orchestration platforms
Without any doubt, microservices changed for good the way applications are perceived. The monolithic application paradigm is rapidly being replaced by a new generation of ultraportable applications that run in containers. No wonder. The isolation offered by containers technology along with the plethora of cutting-edge CI/CD tools available takes applications scalability and security to a new level. However, the incredible microservices architecture also brings new challenges that must be overcome, arguably one of the most notable being container management in multi-cluster environments.
Container orchestration tools automate most processes related to containers’ lifecycle, enabling DevOps engineers to be more productive by freeing them from trivial tasks as manually installing and managing Docker containers. Container orchestration tools also ensure that applications are kept resilient to changes and maintain high availability under any load condition. To achieve such goals container orchestration platforms take control over the following tasks:
- Enforcing containers configuration standards set up by IT staff
- Managing and scheduling of containers according to predetermined parameters
- Provisioning containers following DevOps guidelines
- Dynamically scaling of containers to balance the workload
- Monitoring containers health and logs
- Alerting DevOps team when predefined cluster-wide conditions are met
- Managing containers networking, even adapting it if needed
- Managing containers access to storage volumes and other cluster resources following DevOps and SecDevOps best practices
While it is true that Kubernetes architecture differs from Docker Swarm’s and Mesos’ in many ways, it is also true that, as container orchestration tools, all of them share most of the duties described above. Thus, what would be the appropriate parameters to choose the best platform?
In that regard, this guide will stay away from comparisons based on “performance” or “ease of implementation” since as experts in DevOps consulting services, we know that such comparisons are entirely subjective. Each implementation is different and as such brings unique challenges associated with the requirements of the company. In our opinion, an unbiased selection of what is the best container orchestration platform for your project should be based on objective aspects that are easily measurable and relevant to your deployment scenario.
For the purpose of Kubernetes vs Docker vs Mesos comparison, we choose the following aspects:
2. Out of the box functionality.
3. Integration with other tools.
In the following sections, we will delve into each platform, exploring what was the purpose behind its creation, as well as their key takeaways.
What is Docker
Docker provides developers and DevOps engineers the ability to easily create, deploy, and run applications and microservices into isolated container environments. Thanks to Docker, applications can run independently from the host environment, regardless if it is a virtual or a physical machine. In other words, Docker is a container runtime technology. As such, Docker is capable of managing containers running images within a node, as well as network and data volumes resources. A key aspect to keep in mind though is that Docker was not created as a framework for managing containers and microservices architecture at scale. Instead, Docker was designed to streamline the development lifecycle of applications and services thought containers, which is something where it excels.
Docker key takeaways
Why is Docker needed? Docker enables developers to significantly speed up the software delivery process through the use of sophisticated CI/CD pipelines, enforce application portability (as microservices), simplify application configuration, lower upkeep costs through better utilization of system resources, promote software standardization, and more.
Is Docker a Virtual Machine? No, it is not. Since Docker installations are based on containers, they only use a minimum set of software resources from the host operating system to run the application. Conversely, a Virtual Machine (VM) encompasses a complete operating system along with its virtualized hardware.
Is Kubernetes using Docker? Short answer, yes. Kubernetes architecture works wonders when using Docker, therefore is not uncommon to think of Docker as if it was an integral part of a K8s deployment. However, Kubernetes is not limited to Docker container runtime to function, it can be deployed flawlessly using RunC, cri-o, containerd, and other container run-times.
What is Docker Swarm
Docker Swarm is a container orchestration software that manages and schedules the work of several Docker containers across multiple machines and/or clusters. In other words, Docker Swarm is in many ways a direct competitor to Kubernetes and Mesos. Yet, due to its roots as a single-cluster solution, Docker Swarm fails to scale as efficiently as the other two container orchestration tools.
Docker Swarm key takeaways
What is the difference between Docker and Docker Swarm? Contrary to Docker which was created with the intention of helping DevOps automation (and thus operate on a single node), Docker Swarm was designed as a container scheduler able to manage several Docker instances running on different physical or virtual machines.
How does Docker Swarm work? The concept behind Docker Swarm is quite simple. When multiple Docker hosts enter in “swarm mode” some of them can be configured as “managers” and the rest as “workers” in charge of running swarm services. Docker Swarm’s mission is to keep the desired container state even when one of the nodes becomes unavailable, therefore offering high-availability to crucial processes such as database clusters and more.
Is Docker Swarm the same as Kubernetes? In a sense, yes, they are. Both, Docker Swarm and Kubernetes are container orchestration tools. However, Kubernetes architecture is far more flexible making it a better option to handle higher load demands.
What is Kubernetes
Kubernetes (aka K8s) is an opensource container-orchestration platform, initially developed by Google, capable of automating application deployment, scaling, scheduling, and management. Since its beginnings, K8s quickly became the preferred platform among key enterprise customers, to the point that nowadays Kubernetes dominates the container orchestration market.Given that other container orchestration solutions like Mesos offer similar functionality, the question is, why Kubernetes? What makes Kubernetes architecture so special?
The answer is simple. Kubernetes has evolved. In a short time, Kubernetes went from being a container orchestration tool to a cloud-native platform. This evolution was possible thanks to Kubernetes’ 100% opensource nature, which gave developers the freedom to adapt K8s API to include specific out-of-the-box functionality adapted to different scenarios. Matter of fact, tech giants such as Amazon, Google, and Microsoft have developed their own versions of K8s in the form of AWS Elastic Container Service for Kubernetes (EKS), Google Kubernetes Engine (GKE), and Azure Kubernetes Service (AKS) respectively.
Kubernetes key takeaways
Is Kubernetes free? Absolutely. Kubernetes is 100% free to use opensource software that can be downloaded and deployed in self-managed cluster environments.
Can you use Kubernetes without Docker? Yes, you can. As a container orchestration platform, one of the requirements to deploy Kubernetes is counting with a suitable container runtime software. Certainly, Docker is the most popular container technology but is not the only one capable of working with K8s. Other container runtimes such as CRI-O, Containerd, and Frakti can also be used. So it is convenient to change the paradigm. It’s not about Docker Vs Kubernetes, but how to get more out of the synergy Kubernetes offers when used in conjunction with Docker.
Is Kubernetes reliable? Definitely, it is. Kubernetes will self-heal organically whenever the system is affected, providing unsurpassed reliability thus making it an excellent choice for high-availability systems.
What is Mesos
You can think of Apache Mesos as more than just a container orchestration tool, but more of an opensource cluster manager that provides powerful resource isolation and sharing across cloud environments, independently if the workloads are containerized or not. As Mesos backers like to say, Mesos is more like an operating system for data centers.
However, that is not entirely accurate.
In reality, Mesos is a distributed systems kernel, which is probably its biggest advantage but also its greatest weakness. To understand Mesos’ paradox, nothing is better than a good analogy.
Apache Mesos’ power comes from its ability to abstract CPU, memory, storage, and other resources, just like the Linux kernel do, but at a cluster scale. However, similarly to Linux, deploying applications directly at the kernel level is a daunting task. That is why Mesosphere, a technology company based in San Francisco, developed the incredible Marathon plugin for Mesos, and shortly after, released Mesosphere DC/OS (Distributed Cloud Operating System), an open-source, distributed operating system based on Apache Mesos. You can think of DC/OS like Ubuntu and Mesosphere as Canonical.
DC/OS leverages the power of Mesos to run services, tools, and applications, from the convenience of a modern UI, providing an infrastructure agnostic operating system with built-in self-healing capabilities. Thanks to DCOS, cluster administration using Mesos is remarkably easier. To install distributed CI/CD tools, data services, as well as any other stateful or stateless distributed workload all that DevOps engineers have to do is to use the UI. Although DC/OS is an opensource project, Mesosphere, the company that created and actively maintains it, also offers additional features and paid support to enterprise customers. That’s a key aspect to keep in mind as you will discover soon.
Mesos key takeaways
Is Mesos an orchestration platform? Mesos is much more than a container orchestration platform. One of the biggest strengths of Mesos is its ability to run both containerized, and non-containerized workloads in a distributed manner. In that sense, Apache Mesos can manage container orchestration in a similar fashion to K8s.
Can I run Kubernetes on Mesos? Yes, you can. Although container orchestration is usually managed using Mesosphere’s Marathon plugin, Mesos’ ability to interact with infrastructure at kernel level lets it use Kubernetes as an alternative to manage containers.
What’s the difference between Apache Mesos, Mesosphere, and DCOS? Simply put, Mesos is like the kernel on which DC/OS is based on. On the other hand, Mesosphere is the company actively contributing to both Apache Mesos and DC/OS development. You can think of Mesosphere and DCOS as Canonical and Ubuntu.
Kubernetes vs. Docker Swarm
1. Scalability. Kubernetes was designed and used by Google to manage microservices in multi-cluster environments that consisted of thousands of nodes whereas Docker Swarm has not yet proven to be able to scale at such level.
2. Out of the box functionality. Vanilla Kubernetes installations already count with all tools that a DevOps engineer might need. Docker Swarm is simply not able to compete with K8s in that sense.
3. Integration with other tools. Kubernetes flexibility allows it to integrate with the best opensource (and closed source) monitoring, security, and managing tools in the market. On the other hand, Docker Swarm dependency on Docker creates little interest in developers that prefer building tools for platform-agnostic solutions like Kubernetes.
Kubernetes vs. Mesos
1. Scalability. When Apache Mesos is combined with Mesosphere DC/OS, the result is a platform that offers almost unlimited scalability which is ideal for large systems that require maximum redundancy. Mesos’ ability to handle any type of workload, regardless of whether it is containerized or not, is certainly a deal-breaker that DevOps engineers should take into account during the platform selection process.
2. Out of the box functionality. This is probably the most debatable point of the entire comparison. Without a doubt, both Mesos and Kubernetes offer an incredible level of functionality. However, what may be a decisive factor in the final decision of many DevOps engineers is the fact that Kubernetes offers 100% of its functionality for free and without restrictions. Apache Mesos also is 100% free to use, however, if your project involves using Marathon or DC/OS some of the features you require might not be entirely free. So this is a subjective aspect that will depend on each particular case. In our opinion, Kubernetes has the advantage in this regard, however, depending on the scale of your project, the use of paid functionalities may be irrelevant if you can achieve the desired result.
3. Integration with other tools. Arguably, this may be another point open to debate. For obvious reasons, Mesos tends to have a preference for tools developed by Apache (like Spark) and Mesosphere (like Marathon or DC/OS). This does not mean that Mesos cannot be used with third-party tools, but it is a tendency that can direct you towards the use of specialty tools that only work with Mesos. The amazing popularity of Kubernetes on the other hand makes its API the first choice for developers of all kinds of tools. No wonder, since Kubernetes is the defacto platform for deploying microservices in the cloud. Depending on your project, this aspect could be the one you need to make your mind. Unless you are involved in a huge project needing extraordinary redundancy, Kubernetes might be a safer option than Mesos.
Kubernetes and Docker: The Perfect Synergy
Throughout this article, we have been focusing on the differences between platforms. Mesos vs. Kubernetes, Docker vs. Kubernetes. Instead, why not take advantage of the inherent synergies between them?
Take Docker and Kubernetes for instance. The Kubernetes architecture can greatly benefit by installing Docker as its container runtime. Docker is probably the most mature container technology hence combining it with K8s leverages the best of both.
What about Mesos? Instead of looking Mesos and Kubernetes as mutually exclusive, you could combine their strengths too. Mesos DC/OS – Kubernetes is already being used with great success. While it is true that Apache Mesos’ learning curve is really steep, that could be compensated by a rock-solid solution.
Deciding between Kubernetes, Mesos, and Docker Swarm comes down to thinking carefully about what kind of features your project requires.
- Are you working on a personal project for home or home/office that only involves a few nodes? Then Docker Swarm could be your best option. Easy to deploy, and easy to learn which might be important to you.
- Are you working on a massive project involving several datacenters across different continents? Granted, that could be a somewhat exaggerated scenario, however, it gives you an idea that a project that large fully justifies the use of a high-level platform like Apache Mesos.
- Last but not least, does your project requires an enterprise-level platform capable of running and managing thousands of containers in the cloud? Then Kubernetes might be your best option.