Container Orchestration 101: All Hail Kubernetes
Previously on our blog, we talked about containers and their benefits for your software project. Today, let’s take a step further and discuss the topic of container orchestration, the reasons behind Kubernetes being so popular, and whether your project really needs a container orchestration tool.
Container orchestration explained
Container orchestration is the process of automating, scheduling, deploying, scaling, health monitoring, and managing your containers. To perform all these actions, you need a specialized tool that will take full care of container management.
Now, you might have a question: why do I need a specialized tool when I can do it all on my own? Yes, you can if we talk about several containers. But if you use hundreds (if not more) of containers and each requires an individual set-up and management, you simply won’t be able to cope manually. This is where container orchestration steps in and saves you from spending tremendous amounts of time managing all your containers.
What exactly a container orchestration tool does and how does it help?
Automation may sound too vague so let’s elaborate a bit more on how exactly a container orchestration tool helps keep all your containers up and running.
Most container orchestration tools follow a declarative approach. That means, you simply state the desired configuration state and the system automatically decides on the best way to achieve this state. In this way, the system makes independent decisions about:
- What container images make up an application and in what registry they are located;
- Provisioning containers with resources;
- Securing (and defining) network connections;
- Versioning specifications;
- Load balancing and scalability;
- Container relocation (to achieve better performance and ensure availability).
As you can see, a container orchestration tool takes full responsibility for managing containers, monitoring their health, and adjusting necessary changes if necessary to maintain the desired state of the system. And if you are not yet convinced that container orchestration tools are a must-have, here are a few more benefits.
Scaling and load balancing
As already stated, a CO tool is responsible for monitoring load balance and scaling containers upon necessity. In this way, container orchestration helps with the following:
- The issue of hosts being overused;
- Application of rollbacks and updates to all apps (regardless of their location);
- Load-balancing across multiple servers;
- Enhanced security.
Though being an obvious advantage, automation is worth being mentioned once again. Not only do container orchestration tools automate the majority of processes associated with managing containers, but they also support Agile or DevOps methodologies. In this way, teams can develop and deploy applications in a faster and smoother manner, increasing productivity and the company’s profit.
Smart and automatic allocation of resources helps reduce financial expenses related to project maintenance, which is another big benefit for any company.
The Great and Terrible Kubernetes explained
Now that we are clear on what container orchestration is and what exact benefits it brings, it’s time to talk about container orchestration platforms and Kubernetes, specifically.
The most popular orchestration platforms are:
- Docker Swarm
- Apache Mesos
Among them, Kubernetes is probably the most used and most well-known. Why is it so? Let’s have a good look at it.
Kubernetes, or K8s in short, was originally designed by Google. Fun fact: this internal Google project was first known as Borg - shoutout to all Star Trek fans out there.
Kubernetes is used for all container management activities described above and offers impressively rich functionality. But these are not the only reasons why Kubernetes is so wildly popular and why it’s on top of the list. The biggest arguments in favor of Kubernetes are:
- K8s is an open-source platform: that means, it has a vast and dynamic ecosystem around it and there is a very high possibility you’ll easily find any open-source tool if needed.
- Everything is done through code: by using consistent tools and formats (HELM package manager, YAML files, kubectl) you promote better control over the system, repeatability, and scalability.
- Kubernetes runs everywhere: you can use it in the cloud, you can use it as a hybrid cloud platform, or run it in a colocation (or everywhere at once).
- Minimal fragmentation: K8s is reusable across different environments or configurations and its deployment remains the same regardless of the Kubernetes distribution that you use.
The challenges of Kubernetes governance (and how to overcome them)
Kubernetes is so great because of its vast array of features and capabilities. At the same time, this rich functionality is the exact thing that makes it so complicated and the reason you need an experienced DevOps engineer to handle it.
Below, we list the main challenges one might face when setting up a Kubernetes infrastructure. Don’t worry though - we also listed possible solutions to these challenges.
When we talked about security in our previous articles, we mentioned that the high complexity of the application leads to higher security risks since there are more chances for vulnerabilities to occur. The same applies to K8S: its immense complexity leaves room for possible attacks and, if not managed properly, puts your application at a risk.
So what can you do to enhance Kubernetes security? Here are a few ideas:
- Use security modules like AppArmor and SELinux;
- Enable either role-based access control or apply zero-trust approach towards user authentication;
- Use separate containers so a private key is hidden.
- Prevent access for the Kubernetes API server from outside.
Due to the high number of pods and containers, Kubernetes presents several networking issues:
- Addressing: the inability to use static IP addresses and ports for communication due to the constant changes that happen in a Kubernetes environment;
- Communication: since there are many network communication layers in Kubernetes, it presents several different communication challenges to take care of.
- Interface: there is no native support for multiple network interfaces in Kubernetes which causes issues, especially when deploying VNF applications.
And these are just a few examples (not to mention multi-tenancy or policies). One of the most efficient ways to resolve these issues is the use of a container network interface (CNI) plugin for better integration of Kubernetes into the application’s infrastructure.
General tips on container orchestration
No matter what container orchestration tool you choose, there are some universal tips on container orchestration that are applicable to any software project. See the biggest tips below:
- Establish a centralized way to manage all activities that happen in the product development pipeline and optimize the release process. A big misconception is that container orchestration platforms orchestrate releases - do not fall for that and take care of releases on your own.
- Centralize configuration management in order to avoid duplicating configurations and to keep track of all deployable units.
- Implement a robust process of compliance and security checks into the development pipeline to mitigate possible risks.
- It is highly recommended to use containers for mature deployment processes that require automation. Remember that containers are not a cure-all solution and cannot be used for any project, regardless of its size and complexity.
Finally, don’t forget about DevSecOps and its importance. And if you thought we are done with the “-Ops” terminology, no, we are not. In our future article, we’ll talk about the GitOps process and what it has to do with containerization and its orchestration. So make sure to subscribe to our newsletter in order not to miss our blog updates!
Irina is a professional copywriter with over 7 years of experience in this domain. She loves creating compelling and informative copy that provides readers with all the needed information. Irina is also a frequent contributor to different blogs and websites across different domains.View all articles by this author.