What is Docker Swarm?
Overview
In this article, we’ll review Docker Swarm, its definition and functions in today’s world, and why it has become a popular and significant Docker feature.We’ll also review a few user types, general use cases, and look at some security issues and best practices for using Docker Swarm.
Definition
Docker swarm mode allows you to manage a cluster of Docker Engines, natively within the Docker platform. CLI platform can be used to manage the behavior of, create and deploy application services to a swarm.
Terminology
Swarm: a swarm is made out of various Docker hosts, that all run in Swarm mode and behave as a manager and worker nodes.
Swarmkit: a project that implements Docker’s orchestration layer and is used within Docker to execute Docker Swarm mode.
Node: a swarm mode is an individual Docker Engine participating in the swarm, where they can run simultaneously, or on separate machines.
Task: a Task carries a Docker container and the commands to run inside the container.
The Function
Swarm can help ITs and programmers to maintain the lifecycle of individual containers and perform security checks to the system, monitor and change the number of containers according to the load, coordinate between the containers and the allocate tasks to groups of containers, supply counter failure redundancy if the nodes fail, and execute periodic checks for software across the containers.
Why is it important?
We can see easily from its definition and reading through its various functions that Docker Swarm is quite important for any IT department that is dealing with containers and maintaining their security. One of the essential things is portability. Containers can run on top of virtual machines or servers. Containers can be stored on on-premise platforms or on the cloud. Coders can write a program, put it in a container, and move it in different environments, while maintaining the content, as it is encapsulated within the container intact.
Who uses it?
Docker Swarm is used by various users and for different purposes. It can be used in production, by ITs, programmers and software engineers. The use doesn’t depend really on the scale of the work, as this platform is quite scalable. Docker is used by many Tech companies and many service providers are enabling it on their platforms.
Use Cases
For Decentralized systems
The system doesn’t handle differentiation between node roles at deployment, the Docker Engine handles any kind at runtime instead.
Cluster Management
Using the CLI to create a swarm of Docker Engines where the user can deploy application services, with the integration of the cluster management with the Docker Engine.
Scaling
The user can choose the number of tasks they want to run for each service, with the ability to change the number in real time
And of course many more uses.
For more details, check this website.
Security Issues
The system provides an adequate security system, yet there is a concern about the security of the containers. Major concerns are the intrinsic security of the kernel, and the strict security measures of the kernel and how they interact with containers.
Some people say that if secure and best practices are used, Docker containers can be equally safe with virtual machine, and that most of the errors that occurred were human ones, not caused by a flaw or a hole in the system itself.
Docker Trusted Registry (DTR) is the enterprise-grade image storage solution from Docker. It is installed behind a firewall so that Docker images can be securely stored and managed.
For more info, check this page.
Best Practices
Managing Secrets in the container image exposes it and makes it vulnerable to misuse and jeopardy. The user needs to provide the container with access to the secrets that it will need as it is running, and prior to that.
Use trusted images to set up a trusted registry of base images, which are the only image developers would be allowed to use. Users should use both educational and enforcement controls to prevent the use of untrusted images, which might be malicious ones that might damage the environment.
Secure your runtime environment by applying and namespace and cgroups permissions to isolate access, and control the sphere of influence of each process. Containers can connect to each other inside the same host and across clusters, making their communication invisible to traditional firewalls and networking tools, and limiting the ability to understand and control traffic at a granular level. Therefore, use container-level Nano-segmentation to limit the potential ‘blast radius’ in case a container tries to do something it shouldn’t.
Vulnerability scanning by avoiding letting images with known malfunctions from running in the production environment by using tools that perform periodic security checks. If an active mood was set, establishing and managing security policies across the whole container lifecycle, this can make the containerized environment very secure.
Closing Thoughts
We have seen a brief explanation of the Docker Swarm and its definition. We also went through its functions and how can DS help ITs and programmers. We also talked about why is it important and who uses it, with viewing some of its use cases. On the other hand, we viewed some of the security concerns and presented several best practices.
All in all, we can say that Docker Swarm is a pretty useful tool, once used carefully.
References
Docker Swarm 101
https://www.aquasec.com/wiki/display/containers/Docker+Swarm+101
Docker Security Best Practices
https://blog.aquasec.com/docker-security-best-practices
Swarm Mode Key Concepts
https://docs.docker.com/engine/swarm/key-concepts
Docker 101
https://www.networkworld.com/article/2361465/cloud-computing/docker-101-what-it-is-and-why-it-s-important.html