While Docker is an excellent open-source tool for containerizing software, on its own, Docker tools do not provide the complete solution to deploy applications with complex architectures. This is where integrated container clustering and orchestration services come into their own. Docker orchestration services provide the framework for managing containers over their lifetimes, from creation to decommissioning. A good service should make deployment straightforward, with useful service discovery and efficient networking features.
The aim of any Docker orchestration services should be to achieve zero-downtime deployment, improve resilience and resource utilization, and be simple to use. When developing complicated systems as containers, proper organization and prioritization are required when clustering them for deployment to ensure they correctly package together application code and dependencies and obtain the resources necessary from the physical or virtual hosts they need to operate efficiently.
Kubernetes is now one of the best known and popular open-source container Docker tools, combining cluster tools and Docker orchestration tools to deliver comprehensive Docker orchestration services. Kubernetes also supports the plugin model and already has many stable add-ons available for a range of specific needs. With its excellent scheduling and resource management features, it supports the efficient deployment of containers. Supported by Google and with world-wide adoption and contributors, it is a stable solution with a great range of features. For organizations with limited experience, it is considered to be one of the easiest and best-documented solutions to get started with. Key benefits include the provision of comprehensive enterprise-level containerization and cluster management services. It is a flexible and extensible service, and container isolation delivers enhanced portability.
Openshift is an offshoot development of Kubernetes maintained by Redhat, available as both an open-source service and an enterprise version. Distributed as a Platform as a Service (PaaS), its foundations are Docker as its container technology and Kubernetes as its container orchestration technology. The latest 4.x version also supports CRI-O as the default container engine as an alternative to Docker. Its big draw is the web console that makes application development and deployment as simple as possible, effortlessly managing applications and related resources. It comes with command-line tools and a web-based interface, supporting most of the popular operating systems and interfacing with a lot of the prevalent integrated development environments. The aim of OpenShift is to maximize the options for developers, seamlessly integrating with their existing development environment.
One great feature for new starters is the range of step-by-step tutorials that are available online. Another plus point for OpenShift is the inclusion of the Jenkins open source automation server, which enables simplified continuous integration thanks to the prevalence of plugins and third-party integrations.
OpenShift comes in several variants, suited to the needs of the end-user. OpenShift Online is aimed at developers who build cloud-based applications. OpenShift Dedicated is a fully managed solution available as a single-tenant environment for organizations looking for a low overhead service. Then there’s OpenShift Container Platform aimed at organizations that want full control over their development environment.
This cluster management service was intended to be the standard orchestration management tool running on Docker applications. Its aim was to help end-users create and deploy clusters of Docker nodes is the easiest possible way. However, problems with stability and loads resulting in users moving across to Kubernetes. With the acquisition of Docker by the enterprise cloud solutions vendor Mirantis, Docker Swarm has been earmarked for decommissioning. While support will be provided for the next few years, any enhancement has stopped.
This relatively new and immature service offers a flexible and straightforward workload orchestrator. Its ideal for the deployment and management of containerized and non-containerized applications, supporting Docker but not being limited to Docker, making it an adaptable solution. It also supports on-premise and in-cloud deployment. It was developed to bring orchestration benefits to existing services and offers easy federation at scale. However, Nomad only aims to provide cluster management and scheduling services, relying on third-party tools like Consul for service discovery functions.
Helios is provided by Spotify as an open-source platform for Docker. Using an HTTP API or a command-line client to interact with servers to make running containers across many servers straightforward. Its ability to simultaneously handle multiple HTTP requests helps avoid single points of failure in the deployed system. It is considered a pragmatic solution with no system dependencies that delivers redundant high-availability services while working at scale. However, the use and support of Helios are becoming limited in favor of Kubernetes.
Mesos is a cluster management tool with efficient container orchestration management features. Created by Twitter as an in-house infrastructure management tool, it is now available as an open-source service. While not strictly intended for container management, it includes an efficient framework called Marathon for container deployment and control, which can be used with Kubernetes. Marathon’s general approach to APIs is considered to be far more straightforward when compared to Kubernetes. Marathon aggregates APIs and provides relatively small API resources, whereas Kubernetes offers a wider variety of resources and is based on label selectors. The downside is that it is a complex service to operate when used as a Container Clustering and Orchestration Service.
There is a range of cloud-managed and on-premise container Docker cluster tools that you can use to avoid complex cluster setups and administrative overhead. Choosing the best tool or service for your organization will totally depend on your specific requirements and the complexity of your applications. The tools mentioned here are being used by many organizations for their production pipelines. In ServerBee, we selected Kubernetes as our primary orchestration tool due to the following points:
- Adaptability, flexibility, and portability
- Simple deployment and management tools
- Excellent scalability
- Available as SaaS for the majority of Cloud providers
- Large established user community
- Support for a broad range of environments
- Stable resource utilization
- High availability solutions
- Effective built-in redundancy
- Application load-balancing capability
- Enhanced networking capabilities.
by Stephen M.