Kubernetes is quick changing into an trade normal, with as much as 94% of organizations deploying their providers and functions on the container orchestration platform, per a survey. One of many key causes firms deploy on Kubernetes is standardization, which lets superior customers see productiveness good points of as much as two occasions.
Standardizing on Kubernetes provides organizations the flexibility to deploy any workload, wherever. However there was a lacking piece: the expertise assumed that workloads had been ephemeral, which means that solely stateless workloads may very well be safely deployed on Kubernetes. Nonetheless, the group just lately modified the paradigm and introduced options resembling StatefulSets and Storage Courses, which make utilizing knowledge on Kubernetes attainable.
Whereas working stateful workloads on Kubernetes is feasible, it’s nonetheless difficult. On this article, I present methods to make it occur and why it’s value it.
Do it progressively
Kubernetes is on its solution to being as standard as Linux and the de facto method of working any software, wherever, in a distributed vogue. Utilizing Kubernetes entails studying a whole lot of technical ideas and vocabulary. For example, newcomers may wrestle with the various Kubernetes logical items resembling containers, pods, nodes, and clusters.
If you’re not working Kubernetes in manufacturing but, don’t leap instantly into knowledge workloads. As a substitute, begin with transferring stateless functions to keep away from shedding knowledge when issues go sideways.
For those who can’t discover an operator that matches your wants, don’t fear, as a result of most of them are open-source.
Perceive the constraints and specificities
As soon as you might be aware of normal Kubernetes ideas, dive into the specifics for stateful ideas. For instance, as a result of functions could have totally different storage wants, resembling efficiency or capability necessities, you will need to present the proper underlying storage system.
What the trade typically calls storage “profiles” is termed Storage Courses in Kubernetes. They supply a solution to describe the various kinds of lessons a Kubernetes cluster can entry. Storage lessons can have totally different quality-of-service ranges, resembling I/O operations per second per GiB, backup insurance policies, or arbitrary insurance policies, resembling binding modes and allowed topologies.
One other crucial part to know is StatefulSet. It’s the Kubernetes API object used to handle stateful functions, and presents key options resembling:
- Secure, distinctive community identifiers that allow you to hold monitor of quantity, and detach and reattach them as you please;
- Secure, persistent storage in order that your knowledge is protected;
- Ordered, swish deployment and scaling, which is required for a lot of Day 2 operations.
Whereas StatefulSet has been a profitable alternative for the notorious PetSet (now deprecated), it’s nonetheless imperfect and has limitations. For instance, the StatefulSet controller has no built-in support for volume (PVC) resizing — which is a serious problem if the dimensions of your software knowledge set is about to develop above the present allotted storage capability. There are workarounds, however such limitations should be understood effectively forward of time in order that the engineering staff is aware of the best way to deal with them.
