Kubernetes is an open-source platform for managing containerized applications, workflows, and services. It was originally developed by Google, which used Kubernetes to manage its services in the lead up to open sourcing it in 2014.
Since then, Kubernetes has caught on across the cloud and software development industry. It has a vibrant community learning and contributing to it.
In addition, cloud infrastructure as well as platform service providers, such as Google, Amazon, and Microsoft, each offers its own Kubernetes builds, making business adoption much easier.
So, with all this buzz, you’re now asking, “what is Kubernetes?” and “what is Kubernetes used for?” Our guide will offer you a complete primer to understanding Kubernetes.
Let’s Start with Containers
To answer the question, “what is Kubernetes”, we will need to start by discussing containers.
What is a ‘Container?’
The simplest way to understand ‘containers’ is to see them as mini-operating systems (OS) that only contain the code to run one specific application (source: Google).
Containers vs. Virtual Machines
So, why are containers preferred over traditional computing methods?
Containers are More Cost Effective
Let’s say you have an e-commerce store app that’s seeing a surge of downloads and use on the app store — you now want to keep up with that demand. You need to duplicate your app (or, to be more accurate, create more instances).
In the old, pre-container-way, you would have duplicated both the code your app needs to run and the rest of the supporting operating system (OS), usually a virtual machine (see the diagram above).
In effect, you would have to pay for computing resources that your application doesn’t even need, which then makes scaling-up overly expensive. It will also take more time to load VMs because they’re larger — this slows your ability to respond to demand.
However, with containers, you just need to duplicate the specific code your app needs to run — and nothing else. By limiting the containerized app to only the code it needs to run, your app will need fewer resources when duplicated for multiple users.
It’s also a much smaller file (usually the size of a podcast file), so in most cases, it can load-up instantly, which lets you respond to a spike in demand much more quickly.
It’s Easier to Move Containers Between Different Computing Environments
Another benefit of containers is that moving your app between environments, such as testing and launch, is also a lot quicker and easier. It already has all the code it needs to run, so that frees you from worrying about the underlying OS or hardware.
From servers, workstations or laptops, or just “bare metal” computer hardware, you can deploy containers anywhere. You can also house microservices into containers, which drives DevOps, an approach to accelerating software development and making it more cost-effective.
But containers are just one side of the equation.
You must also have the means to manage them as well.
In most cases, you have multiple containers supporting one application — you need those containers to ‘speak’ to one another. This is where Kubernetes is essential.
What is Kubernetes?
So, what is Kubernetes and how to use it?
Kubernetes is an open source system for managing, automating deployment, and scaling your containers, or your containerized applications. It operates at the container level, so it doesn’t come with hardware in of itself; you will source hardware independently from a cloud host or your own data center.
What is Kubernetes Used For?
You can use Kubernetes in a variety of ways.
Scaling Your Deployment to Meet Increased Demand
Let’s return to our e-commerce store app example. If there’s a surge of demand for that app due to Black Friday or Boxing Day rush, you could use Kubernetes to rapidly activate new instances of your containers and satisfy the demand spike. In turn, you avoid crashes, delays, errors and other issues that will inconvenience your customers.
Load Balancing & Disaster Recovery
If you work with a public cloud hosting provider, such as Amazon, Google or Microsoft, you can also deploy your containers across different regions. This helps build redundancies and ensures high availability rates in case a data center fails in one area.
Similarly, if your app is struck by a cyber attack or critical error, you can recover more easily.
Simplifying Updates & Bug Fixes
Your e-commerce store app might rely on multiple containers. For example, the application is on one container, but the database is on the other. However, you learn that the user interface, i.e., the application container, has a security vulnerability.
When you fix that vulnerability in the application container, you don’t have to worry of messing up the database. They’re independent of one another, so changing one doesn’t affect the other.
This simplifies updates and bug fixes by saving development time and cost as well as reducing risk, such as an application crash (and inconveniencing the customer).
Besides the examples above, companies use Kubernetes to develop faster and reduce their time-to-market, get visibility, lower hardware costs, improve app security, and more, which we discuss in our article about the benefits of Kubernetes.
What are Kubernetes Pods, Nodes & Clusters?
By now, you should be familiar with containers, (you can revisit the earlier section), but those are only one part of Kubernetes.
A Kubernetes Deployment at a Glance
Source: Kubernetes Bootcamp
In fact, you can think of containers as the smallest unit in Kubernetes, from there, you would work with nodes, pods, and clusters.
What is a Kubernetes Pod?
In Kubernetes, a ‘pod’ is a wrapper that contains one or multiple containers.
In most cases, a pod usually houses one container, though there are rare cases where you could have two or more containers in a pod.
Example of a Pod
For example, your e-commerce store could have its container app as well as another container to collect logs or activity about who’s accessing your app, in one app.
Overall, the pod is Kubernetes’ most basic form of deployment.
What is a Kubernetes Node?
The next Kubernetes stage is the ‘node’, which is basically the physical server or the virtual machine (VM) that’s running your pods. In either case, just consider the node as the actual resources you have at your disposal to run your application.
Each Kubernetes node can support one or multiple pods. Within Kubernetes’ framework, the node helps with ensuring your app has sufficient resources to keep running.
What is a Kubernetes Cluster?
A Kubernetes ‘cluster’ is basically a grouping of nodes.
In a way, you could think of a cluster as a data center. But if you deploy Kubernetes with a public cloud host like Google, you wouldn’t put all of your eggs in one basket, or cluster.
Instead, you would put your pods in multiple clusters so that your app will remain active, even if one cluster goes down. So, even if a data center goes down, your customers will still be able to access and use your e-commerce app.
In fact, this is a critical aspect of developing for the cloud — you develop with the expectation that the system will fail. With the ability to leverage multiple clusters to host your application, Kubernetes facilitates that kind of development.
What is a Kubernetes Manifest?
A Kubernetes Manifest is a place where you define all of the properties you want to deploy using Kubernetes. In other words, you’re basically telling Kubernetes everything about your application — how it works, what it connects to (such as databases), the services it uses, etc.
What are Your Other Deployment Options?
As you might imagine, Kubernetes — or for that matter, containerization — aren’t necessarily your only deployment options. You can deploy, manage, and scale your application in other ways, but as you’ll see later on, these alternative approaches present major challenges.
The Challenge of Using Virtual Machines
If you’re not using Kubernetes and containers, then you’re likely deploying your application through VMs. In the container section of our post earlier, we noted that relying on VMs is much more expensive and resource-intensive than containers.
You’ll basically pay for computing resources meant to run an entire OS instead of just the specific code you need to run your application. This will translate into higher-cost OPEX for managed cloud services and if you own your own data center, costlier CAPEX.
It’s More Time Consuming
Let’s say you want to update your e-commerce store app with a new user interface or give it a new payment portal. In a VM-based architecture, you would have to log into every VM, manually update the application code, and then re-start it.
During this process, you would also have to remove the VM from serving any traffic, so this will also reduce the number of resources available to support your users.
Likewise, if you get a spike in online store traffic (e.g., Black Friday), then you’ll need to again login into each VM and spin up new instances. This will need time as it requires setting them up, provisioning, installing, and testing before pushing to live.
That time gap could put you at risk of delivering a bad shopping experience to your customers and, even if you do scale in time, use of valuable developer resources.
In contrast, Kubernetes automates that entire process, be it to update your app or to scale it so that it adjusts to a spike in demand.
Alternatives to Kubernetes
If containerization is your way forward, you’ll find that Kubernetes is just one of several major options for managing your system. These include Pivotal Cloud Foundry and Docker Swarm.
Pivotal Cloud Foundry
The biggest advantage of using Pivotal Cloud Foundry (PCF) is that you can agnostically send your applications to any cloud host and any data center. So with PCF, you can move your code from Azure to Google to Amazon seamlessly.
However, PCF’s main drawback is its cost. You’ll have to pay for the application instances and service instances, and these costs can add up very quickly.
Docker Swarm is a Kubernetes alternative, however, it’s not as widely adopted as Kubernetes and it’s also more expensive. The lack of adoption will make it harder for you to source talent or developers to support your system, which can add to the cost of maintaining your system.
Thanks to its open-source nature, Kubernetes is not just widely supported, but it’s viewed as the industry standard for containerization.
You can get Kubernetes orchestration suites from the top managed cloud hosting providers, including Amazon, Microsoft, and Google, and draw on a growing pool of developers. To see how easy it is to start with Kubernetes, see our article on the Google Kubernetes Engine.
Kubernetes already makes up the majority of Google and Microsoft’s containerized workloads, and making its way through Amazon as well (see the graph below).
A big driver for that growth is the fact that businesses, including yours, want to hit the ground and run — or, to be more accurate, sprint — with their container deployments.
But adopting an existing Kubernetes build will only get you partway there, you need DevOps expertise to take you the rest of the way. And that can take time, time that you might not have when it comes to overtaking your competitors. That’s where working with an outside partner to rapidly build your solution and up-skill your own team is critical.
At Techolution, we build usable market-ready solutions within weeks of starting the project. Why spend half a year when you can deploy an automated, easily scalable, and highly functional app before your competitors? Let’s talk!
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