Kubernetes Operators vs HELM: Package Management Comparison
While Kubernetes has become the standard platform for container orchestration, managing complex application lifecycles can still be a challenge. That's where Kubernetes Operators and Helm Charts come in. This guide dives into both of these tools to explain what they do, how they're different, and their ideal use cases. Whether you're new to Kubernetes or seeking clarity – this article is here to help!
Kubernetes Operators extend the Kubernetes API, encoding the operational knowledge needed to automate complex lifecycle management tasks. Helm Charts, on the other hand, provide a standardized packaging format, simplifying installation, upgrades, and management of applications.
Let's start by exploring the fundamentals of Kubernetes Operators and Helm charts before diving into how they compare.
What is a Kubernetes Operator?
A Kubernetes Operator is a subcategory of controllers, which is a custom control loop that extends the Kubernetes API. It enables users to manage and automate the deployment, configuration, and lifecycle of complex applications within Kubernetes clusters. By leveraging the Kubernetes control loop, operators function as controllers for optimizing the state of resources.
Operators extend this controller functionality to stateful applications like databases, caches, monitoring systems, and more. These applications traditionally require intricate domain expertise, but Kubernetes Operators simplify the tracking and management process, making it accessible to anyone. Operators streamline the installation dependencies and connections between services within the application stack.
While Kubernetes Operators primarily benefit network features within the node, they can also optimize the hardware infrastructure used for the nodes by leveraging features like node-affinity.
Additionally, Kubernetes Operators encapsulate the operational knowledge and best practices for running a specific application, encoded as software and deployed as a container. They leverage Kubernetes's Custom Resource Definitions (CRDs) to define and manage custom resources, effectively creating a domain-specific language for managing the application's lifecycle.
The key aspect of Kubernetes Operators is their continuous function of turning the desired state into the actual state within a node. This crucial feature will help distinguish between a Kubernetes Operator and a Helm chart once we explore Helm chart's features.
Examples of Kubernetes Operator
There are a handful of Kubernetes operators which you can implement. One example is the Prometheus Operator, which simplifies the deployment and management of the Kubernetes’ Prometheus monitoring stack. It provides custom resources for defining all Prometheus instances, alerting rules, and service monitors. The operator automates tasks such as deploying and configuring Prometheus servers, configuring data sources, and managing the lifecycle of Prometheus components.
There are many other versions of Kubernetes operators such as Kafka, Elasticsearch, and more. Similar to how the Prometheus Operator controls all instances of Prometheus in the cluster, these other Kubernetes operators work with their respective systems to influence interactions within the cluster. Each of these different Kubernetes operators has its own application type, installation method, configuration options, etc.
There are many different types of Kubernetes operators, but only one example should suffice for understanding an operator's capabilities. With the established information on what Kubernetes operators do, we can now dive into what Helm charts do
What is a Helm Chart?
A Helm Chart is a packaging format for Kubernetes applications that bundles all the necessary Kubernetes resources into a single package. These resources include items such as Deployments, Services, ConfigMaps, and Secrets. Helm charts provide a standardized way to package, distribute, and install applications on Kubernetes clusters, and all of this information can be found inside a comprehensive directory.
On top of all these capable services for Helm charts, they can also perform important processes of Kubernetes like ingress controlling and implementing PersistentVolumeClaims (PVC). Ingress controllers influence how external, incoming traffic is allowed to enter the Kubernetes services. This can help to limit traffic for optimal speed and security purposes. On the other hand, PVC is a service that makes sure ample storage is allocated for all stateful data.
Also, the Helm charts contain additional pieces of information such as templates for YAML manifests, values files for default YAML configurations, rich metadata, and more. Basically, the chart is a fully-stacked hub for all information in your Kubernetes cluster. Additionally, users can implement parameterized upgrade logic to seamlessly streamline version upgrades and license all information that is attached to an application.
Overall, Helm itself is a package manager for Kubernetes, similar to apt or yum for Linux distributions, which simplifies the installation, upgrading, and management of applications.
In contrast with a Kubernetes operator, a Helm chart is a single use method for provisioning the resources of the desired state. Unlike Kubernetes operators, Helm charts cannot access the actual state.
Helm Chart Examples
There are many different versions of Helm charts, such as MySQL, Redis, Jenkins, and more. Let’s compare the Prometheus Helm chart. It provides a packaged way to deploy the Prometheus stack, including the Prometheus server, Alertmanager, and other components. It simplifies the installation process and allows you to customize the deployment through configuration values. However, the chart itself does not automate the ongoing operations or management of Prometheus within the cluster.
As mentioned earlier in the section on Kubernetes Operators, some services like Elasticsearch and Grafana have versions that serve the purposes of both Kubernetes Operators and Helm charts. While these features are able to influence the processes of both, it is important to understand that they are different functions before implementing controllers for your Kubernetes nodes.
Orchestrate Gateways in K8s: End-to-End Lifecycle Management with Gateway API
When to Use Kubernetes Operators vs Helm Chart?
Since we have described the functionality of Kubernetes Operators and Helm charts, it should come as no surprise that they are a couple of the go-to options for managing complex applications and deployments on Kubernetes. But there is one main question you may be asking yourself - when would I want to use one over the other? While they do tend to handle many of the same processes, there are specific instances where one of them would excel over the other. Their specified optimal use cases are crucial to know in order to maximize the potential efficiency they possess. By understanding their key differences and when to ideally use them, you will be better equipped to make decisions for your own applications.
There are two main applications where both Kubernetes Operators and Helm charts have their own advantages and disadvantages: application distribution and installation. Let’s go over these use cases and how each will shine differently.
Application Installation
Another major use case for both Kubernetes Operators and Helm charts similarly influences applications, although in a different way - application installation. While we have already gone over the benefits of application distribution across services with Helm charts and Kubernetes Operators, they can also heavily affect the installation of applications before there is a need for users to regulate the distribution.
For Helm Charts, the previously stated pre-packaging incorporates all files and templates into one seamless bundle. Using these files, specifically the ones with values, Helm controls configuration through preset installation parameters. During installations, Helm charts use the package files and configuration information to perform templating transformations to template YAMLs. These files that are prebuilt into the Helm charts are complete with all components necessary for any installation. With Helm, the chart versions make maintaining and updating these installed apps seamless, and they are incredibly accurate in their predictability. The drawback of this format is that Helm charts focus on stateless apps instead of other management states.
As for Kubernetes Operators, the packaging of the applications are different from that of the Helm charts. While Helm charts are all-in-one packaging, Kubernetes Operators package core logic separately from any application manifests. For configuration, Kubernetes Operators requires CustomResources to create the format which will be specifically catered to the users needs. To get the most out of your Kubernetes Operators, the users will need to implement particular resources or services after its base installation. The predictability and upgrade support of Kubernetes operators relies on the user to monitor and manually install updates when need be. However, this comes with additional benefits that may not be available with Helm charts. Kubernetes operators are capable of state managing facilities like databases, caches, and more. This grants Kubernetes Operators higher versatility and creative application than that of the straightforward Helm charts.
Overall, for complex applications with intricate lifecycle management requirements, advanced configuration options, or custom resource definitions, Kubernetes Operators are often a better choice. Operators provide a more robust and flexible approach to managing the application's lifecycle, automating operational tasks, and encapsulating domain-specific knowledge.
Application Distribution
For distributing applications on Kubernetes clusters, Helm charts provide a more straightforward and standardized approach while Kubernetes Operators allow for more versatility at the cost of more user input.
Helm charts package all the necessary resources into a single bundle, making it easy to share applications across different environments. Helm charts are well-suited for deploying applications with a predefined configuration and structure. In other words, Helm charts are all-in-one functions that serve one primary purpose, so the user does not need to do any additional work to have them perform optimally. These charts that perform the task are also shown in centralized repositories, which can store and share chart metrics. Also, the update versions of Helm charts depend on the version of the applications being used, and update very smoothly across the system.
Similarly, Kubernetes operators are capable of performing similar actions that Helm charts do, but there is a caveat. There is a lot more emphasis on the developer’s ability to create custom resources that focus on specific purposes. Using Kubernetes operators, developers can perfectly track, influence, and control factors of their applications with more specificity than Helm charts may allow. With this functionality, it requires more knowledge and work from the developer’s perspective but it can give a more unique and accurate outcome for the ideal use case. Unlike the centralized repository of Helm charts, Kubernetes Operators do not have a respective hub for their information and rely mainly on GitHub. Also, due to the flexibility that Kubernetes Operators grants, unifying the versions can be tricky with needing to use semantic or calendar based updates.
Key Differences of Kubernetes Operator and Helm
Capabilities and Functionality
Both Helm charts and Kubernetes operators offer an extensive list of capabilities and functionalities, but they do have different use cases where they can be optimized.
Helm charts are primarily focused on packaging and deploying applications. As previously stated, Helm charts come pre-equipped with packaging and valuing capabilities. This allows for a very low-maintenance experience for any user who wants easy regulation of applications in these ways.
In comparison, Kubernetes operators offer more comprehensive lifecycle management and operational capabilities for complex applications. While this does require more work on the developers end, the variability of implementations for Kubernetes operators helps the users to pinpoint certain functionalities they want for a more personalized experience.
Complexity and Flexibility
Between Kubernetes operators and Helm charts, the level of complexity and flexibility that the user desires would heavily influence which one to choose.
Kubernetes operators are generally more complex to develop and maintain, but they offer greater flexibility and customization options for managing application lifecycles. They require more energy and effort on the developers' part, but yield a much better result in terms of flexibility and compatibility for the time spent. They are complex in the sense that they can serve many additional purposes when used in experienced hands, which in turn also grants flexibility to span a greater surface of influence.
Helm Charts are much simpler and more standardized, which has its own upsides and downsides. Due to this simplicity and standardization, there is not much of a need for developers to interact with the service to maximize its impact on the intended task. The drawback of this is that it may lack advanced functionality for certain use cases since it cannot be custom tailored to the needs of the developer.
Customization
Working in tandem with complexity and flexibility, the customization element is where the difference between Kubernetes Operators and Helm charts really shows.
Kubernetes Operators allow for more granular customization and configuration of application deployments, as they can leverage custom resources and controllers. For example, Kubernetes Operators can extend applications like Kubernetes APIs to define custom resources (CRDs) for managing and representing certain application specific entities. There is more creative application and interactions with other services within Kubernetes for Kubernetes Operators.
Helm Charts offer limited customization options beyond the predefined values in the chart. Unlike Kubernetes Operators, they are unable to work in tandem with applications like Kubernetes APIs and work solely for their predetermined purpose. They are only able to use the existing Kubernetes resources that they come equipped with.
Cloud Cost Optimization
With the additional versatility and flexibility that Kubernetes Operators allows, it may also affect costs in a cloud-based environment.
Kubernetes Operators may incur additional cloud costs due to the resources required to run the Operator itself. Developers must be aware of these effects to cost so that they do not accidentally overspend on their application management tools. So, ultimately the developer or company needs to weigh the cost of the additional cloud usage against the benefits the Kubernetes Operator grants in return.
On the other hand, Helm Charts are typically more lightweight and have lower overhead costs due to its simplicity. So, if companies are not willing to spend more on their cloud services, then Helm charts may suffice for the desired budget and requirements.
Learning Curve
The learning curve between Helm charts and Kubernetes Operators is likely where the main choice will be made from a development standpoint. Depending on the experience level of the developers, the amount of time one is willing to spend on maintaining the services, and how mentally invested someone is wanting to be in the implementation process, a clear decision can be made between Kubernetes Operators and Helm charts.
Kubernetes Operators are much more demanding in the sense that users need to have a more thorough understanding of Kubernetes APIs and CRDs. This requirement is necessary to get the most out of the Kubernetes Operators for a business's needs. For more seasoned Kubernetes developers or people who are looking for a challenge in a more introductory developer role, Kubernetes Operators would likely be the ideal way to go. Plus, being well acquainted with Kubernetes Operators makes a developer's knowledge ultimately more valuable and well-rounded.
Helm Charts have a relatively lower learning curve compared to developing and deploying Kubernetes Operators. Since they come relatively standardized and have more of a hands-off approach to their functionality, Helm charts are ready to go as soon as they are implemented. It might just be a learning curve to change the values set in the Helm charts or the ability to see how they are creating a difference, but other than that, they are pretty low mental strain to use.
Operational Automation
With the knowledge and background of Kubernetes Operators, developers can influence the operational automation to far surpass that of the Helm charts.
Don’t get me wrong, Helm charts do offer automation for installation and upgrades, but it is very basic. It does not offer any additional or advanced automation capabilities.
This is where the Kubernetes Operators shine. For application lifecycle management like automated deployment, scaling, backup, and recovery, Kubernetes Operators allow for a higher level of automation and passive user involvement than that of other solutions. While it does require some more work upfront, the long term benefits of automation far outweigh the initial strain on the developer for implementation.
Lifecycle Management
Similar to their operational automation differences, Helm charts and Kubernetes Operators vary in their lifecycle management capabilities.
Due to its depth and variety, Kubernetes Operators excel at managing the complete lifecycle of complex applications. This includes features like deployment, scaling, upgrades, backups, and recovery, which could be time consuming to manage individually. Kubernetes Operators streamline the lifecycle tracking and management processes to take long term strain off the developer.
Similar to its simplistic disconnect with automation, Helm Charts lack in their ability to track all aspects of the lifecycle in the way Kubernetes Operators do. Helm charts primarily focus on installation and basic upgrades, and excel in these cases. However, they in turn lack thorough lifecycle management capabilities in their Kubernetes applications. In order to provide comprehensive lifecycle management with Helm Charts, you'd need to incorporate a third-party system like Argo CD, Flux, or other GitOps frameworks to serve as a framework for managing the entire application lifecycle.
Upkeep and Maintenance
When it comes to upkeep and maintenance, the simplicity of Helm charts is seen as a huge benefit compared to the intricate nature of Kubernetes Operators.
With more moving parts and user demands, Kubernetes Operators require more maintenance effort due to their complexity. Additionally, developers need to keep the Operator code up-to-date with application changes or they risk breakdowns of the application. If the developer is kept well informed and is on top of all necessary features of this maintenance, then there should be no problem with using Kubernetes Operators in thorough capacities.
In contrast, Helm Charts are generally easier to maintain through the sheer fact of their simplicity. Logically, it makes more sense that something with less moving parts and user interactions would be easier to maintain. Through their standardized packaging formats, Helm charts achieve this low stakes user upkeep by continuing to be self-sufficient with all updates and minor fixes.
GitOps Alignment
GitOps is a developer's best friend. It is likely that they have experienced or used GitOps for Kubernetes related applications. This testament stands for Kubernetes Operators and Helm charts, as they both interact with GitOps in some way.
Both Kubernetes Operators and Helm Charts have the capabilities to be integrated with GitOps workflows. Specifically for Kubernetes Operators, their ability to manage custom resources and leverage APIs may provide a more seamless integration with additional GitOps configurations.
While it does have the capacity to adapt with GitOps workflows, Helm charts struggle to easily integrate them due to their simplicity. While it is capable of working in tandem with GitOps benefits, it might just require more work from the developers perspective in order to make the most out of the pairing.
Community and Support Ecosystem
When it comes to learning resources, help with fixes, and overall talk about the applications, having an online community and support ecosystem is a huge plus for implementing new services in a business.
Helm has a larger and more well-established community and ecosystem, with a wide range of publicly available charts for various applications. This is due to the sheer time that Helm charts have been available in comparison to Kubernetes Operators. Since it came first, Helm charts have had more usage, testing, and content made available to the development community. For these reasons, developers may be more well acquainted with the service as opposed to the newer Kubernetes Operators.
While it does not have as long of a life as Helm charts, Kubernetes Operators have a fast-growing ecosystem of passionate developers. It may catch up in years to follow, there are some roadblocks that may prevent that from happening. The main issue is how the availability and maturity of Operators can vary across different applications. There is a potential for the services’ information to be unified across services, but we cannot be sure at this moment.
Kong Ingress Controller's Role in Helm & Operators
Kong Ingress Controller simplifies the management of ingress traffic in Kubernetes clusters. You can deploy Kong Ingress Controller using either Helm Charts or Kong Gateway Operator. The Kong Ingress Controller Helm Chart provides a straightforward way to install and configure the Ingress Controller on a Kubernetes cluster. While the Kong Gateway Operator offers more advanced lifecycle management capabilities, with the ability to leverage custom resources for configuration.
Both deployment options offer their own advantages depending on your needs and preferences. If you're looking for a quick and straightforward deployment, the Helm Charts might be the way to go. However, if you require more advanced lifecycle management capabilities and prefer a more declarative approach to configuration, the Kong Gateway Operator might be the better fit.
Conclusion
Now, you should have a comprehensive understanding of the features, functions, and capabilities of both Kubernetes Operators and Helm charts. While they are different processes, they are often complementary to each other.
Helm, as a tool, and the charts (provided by the community) can be thought of as a package manager. Its purpose is to install or update a packaged solution into your Kubernetes cluster. It's a tool that you typically use once per installation or upgrade. While there often is a choice between Helm charts and Operators, do note that Helm charts can be used to install Operators in the cluster. For example, Kong provides a Helm chart to install the Kong Gateway Operator.
Helm charts provide a simple standardized packaging format to simplify installations and allow for basic management of applications. It is a more hands-off approach for developers, as it does not require much more work or upkeep once it is installed. The only additional things required by the developer are the ability to read the charts' information and modify any values as seen fit.
On the other hand, Kubernetes Operators offer a more advanced, specified solution tailored to a company's specific needs through modular adjustments from the developer. An Operator is installed in your cluster and remains there until you uninstall it or remove the cluster. It is much more customizable and offers more in-depth management capabilities than Helm charts, but this, in turn, requires a more hands-on and informed approach from the developer implementing it.
The choice between using a Helm Chart or a Kubernetes Operator depends on a number of factors, including the specific requirements of the application, the level of complexity or customization needed, and the operational expertise combined with available resources. There are many different versions of them from various companies, so the next step is to find the right ones to fit your specific needs. Please feel free to check out Kong Ingress Controller as a solution, and good luck with all your future Kubernetes endeavors.