Kubernetes (K8s) is an open-source container orchestration system. 4 Creating a Service for the StatefulSet; 8. Now let’s talk about StatefulSets. If your application is stateless, you should use Deployment and not StatefulSet. Reading Time: 4 minutes In Kubernetes we find different resources for deploying applications such as Deployment Statefulset daemonset In this blog, we will. 2. The volumeClaimTemplates automatically creates a new PersistentVolumeClaim each time a pod is replicated. The StatefulSet controller uses this field as a collision avoidance mechanism when it needs to create the name for the newest ControllerRevision. Ordering: Kubernetes StatefulSets ensure that each pod is created in a specific order, while Deployments do not. They guarantee stable and unique network identities, stable and persistent storage, and deployment and. - Storage: As many VolumeClaims as requested. The below example demonstrates the components of a StatefulSet. yaml. The simple scalable deployment is the default configuration installed by the Loki Helm Chart. a cache or database cluster even though it may solve your specific situation as. DaemonSet vs. IIRC this is different with Deployment related storage and could cause data loss if not cautious enough. Let’s understand both. e. Kubernetes deployments manage stateless services running on your cluster (as opposed to for example StatefulSets which manage stateful services). Deployment is best suited for stateless applications while StatefulSet is best suited for stateful applications. What then is the advantage of using StatefulSets?而因為有關聯，所以在Deployment下的Label Name，會同樣印在pod上。. Unlike in a standard Deployment, StatefulSets are aware that your application is stateful and will therefore treat it accordingly. Using StatefulSets to run Stateful applications. In statefulsets each replica pod created has an index number starting from 0 and it will only setup the next replica if the previous one is running. The database and Kubernetes itself run on the same machines. Kubernetes provides a variety of controllers that you can use to define how pods are set up and deployed within the Kubernetes cluster. Deploy it using the command below: $ kubectl apply -n test-namespace -f deployment. 5, we’ve moved the feature formerly known as PetSet into beta as StatefulSet. Statefulset vs. 1. Through StatefulSets, each Pod receives a stable, unique identifier, maintaining predictable and orderly deployment, which is indispensable for the. g. Deployment. For the node affinity we could use node selector. Kubernetes Deployment vs. com. But still for the alertmanager statefulset, only 1 pod is getting restarted. In short, a StatefulSet is an API object in Kubernetes that handles stateful applications. StatefulSets also guarantees the ordering of the pod deployment and its scaling. Deployments vs StatefulSets vs DaemonSets. There is a separate controller. 05, 2023 Image: Shutterstock / Built In Kubernetes is a powerful container orchestration tool that provides a variety of resources for managing containerized applications at scale. Gère le déploiement et la mise à l'échelle d'un ensemble de Pods, et fournit des garanties sur l'ordre et l'unicité de ces Pods. Ordered, automated rolling updates. StatefulSets are the native Kubernetes resources to manage stateful applications. Ésta publicación muestra tres formas diferentes de implementar una aplicación en pods de Kubernetes. io/v1beta1 metadata: name: deployer. Their purpose is to keep a set of identical pods running and upgrade them in a controlled way. The support for autoscaling the statefulsets using HPA is added in kubernetes 1. Each new pod in statefulset then have a new PV attached to them to. As of Kubernetes v1. service都有ClusterIP,可以负载均衡 StatefulSet适合场景有状态的应用特点1. Deployments use ReplicaSets as a mechanism to orchestrate Pod creation, deletion, and updates. We can use the kubectl describe secret command to display additional information about the resource. This process requires users to familiarize themselves with various k8s resource objects, learn many MySQL operation details and maintain a set of complex management scripts. The StatefulSets are mostly used for deploying Stateful applications where we require a unique network identifier or Storage. In statefulset pod`s names are in sequential order on the other hand in. To help deploy Pods, Kubernetes provides three different options: Deployments, DaemonSets, and StatefulSets. In this video I explained about StatefulSet in Kubernetes, the differences between Deployment Vs StatefulSet in Kubernetes, Why do you need statefulset in Kubernetes, so you will understand Statefulset in Kubernetes completely. To provision a static PV for a Deployment workload, the procedure is as follows: Note: The examples in this section. Their hostnames include their numerical replica identifier, allowing external applications to interact with the same replica after a Pod’s rescheduled. 1. StatefulSets and DaemonSets. (順番を担保した削除と終了) 参照：Using StatefulSets. Deployments - Semaphore 24 May 2023 · Software Engineering Understanding ReplicaSet vs. 安定したネットワーク識別子. 3343 Perimeter Hill Drive. StatefulSets. Unlike Deployments or StatefulSets, which manage the deployment of Pods on a per-replica basis, DaemonSets manage the deployment of Pods on a per-node basis. If you want to provide workload persistence using Kubernetes persistent storage, you can incorporate a StatefulSet into your solution. Let's be friends: Explore managing stateful applications with Kubernetes StatefulSets — when to use them, how to deploy MongoDB. . [Sonarqube statefulset] Provide option to switch between statefulset vs deployment for sonarqube. In this exhaustive blog post, we will unravel these strategies layer by layer, backed by real-world scenarios and meticulously explained code examples. Apr 6, 2020 at 8:53. Conclusion. Deploy the Java service to Amazon EKS. StatefulSets currently require a Headless Service to be responsible for the network identity of the Pods. Deployments, StatefulSets, and DaemonSets allow you to scale up your Pods, roll out new images and configurations, and more. All the examples available are showing Redis cluster being deployed as a combination of Kubernetes’ StatefulSets and PersistentVolumes. This deployment mode is the easiest way to deploy Loki at scale. Create Some Data. We will take the example of Cassandra to learn about statefulset upgrade feature . Stable Network Identities: StatefulSets provide stable network identities for each pod, making it easy to communicate with specific pods in the set. Once kubectl apply/create is performed, noticed that three persistent volumes are created dynamically. RollingUpdate: The RollingUpdate update strategy implements automated, rolling update for the Pods in a StatefulSet. StatefulSet is the workload API object used to manage stateful applications. As a workload API object, a StatefulSet is used to manage stateful applications. summary, it is possible to set min / max replicas for a statefulset using HPA. DaemonSets, StatefulSets and Deployments are three ways to deploy workloads in Kubernetes. Statefulsets only provide a way to have unique naming e. 22. StatefulSet Kubernetes | Understand what StatefulSet in Kubernetes is and how it works Using StatefulSet in practice 🙅🏼♀️ youtu. I want to deploy a single Pod on a Node to host my service (like GitLab for the example). The annotation does not need to. The key difference between stateful and stateless applications is that stateless. Deploy the app to Kubernetes: kubectl apply -f deployment. Instead you create Deployments and StatefulSets where a controller takes care of that. Modelling Stability with StatefulSets. 2. A pod in a StatefulSet can fail, but the persistent pod identifier will enable. Statefulsets implement this sticky identity in two ways: Predictable Pod Names: Statefulsets have fixed ordered name in the form of: ${statefulset-name}-{ordinal}. persistent deployment manifest: As you can see its straight forward. k8s. in general you should refer to the "Using StatefulSets" in. I have a cluster on gke with apache, mysql and keyrock and i would like to scale it up with horizontal pod autoscaler. yaml with this way of working, it is easy to store the yaml-files in Git so you have full control of all changes and can revert/rollback. I have chosen this option since we are using a single node MariaDB, which works better as a statefulset than as a deployment. yaml. You use StatefulSets when your pods need to maintain some sort of unique state -- for example, the volumeClaimTemplates section of the manifest means that each pod gets a unique PersistentVolumeClaim. StatefulSet is used to manage stateful applications: It manages the deployment and scaling of a set of Pods. Statefulsets is used for Stateful applications, each replica of the pod will have its own state, and will be using its own Volume. This blog post will discuss how this feature can be used. A big advantage of Kubernetes and StatefulSets is that you can scale the number of MongoDB Replicas up and down with a single command! To scale up the number of replica set members from 3 to 5, run this command: kubectl scale --replicas=5 statefulset mongo. The output of the describe command in this example is the following: Name: nginx-app1. 60. 0 or above. Stateful applications are those which required persistent storage to work aptly. Just to avoid data corruption if you are changing the replica to more then one. It is a simple application to start with since it does not require a complicated setup and it cannot be scaled. It should not be confused with vertical scaling, which means allocating. Databases such as MySQL and PostgreSQL are examples of applications that are deployed using StatefulSets. 🚀 KubeSphere v3. You may recall that the Deployment controller can perform the update in two ways, depending on the. They keep unique identities for each Pod they manage and use the same identity when Pods need to be rescheduled. 5 Post deployment tasks; 8. DoK #49 Deployments vs. All three of these are defined via YAML configuration, are created as an object in the cluster, and are then managed on an ongoing basis by a Kubernetes controller. Pods hold the containers for an application. g. e. StatefulSets are a Kubernetes resource specifically designed to manage stateful applications. On an update the existing Pods will get deleted and recreated. Introducing Client-Side Field Level Encryption and MongoDB 5. Horizontal scaling means deploying more pods in response to increased load. Why use StatefulSets. 3343 Perimeter Hill Drive. Deploying a MongoDB Database: Here is an example of how to deploy a MongoDB database using a StatefulSet in Kubernetes. These controllers can be used to group pods together according to their runtime needs and define pod replication and pod start up ordering. Pods created by a StatefulSet have a unique and stable network identity. statefulSet {. Related. StatefulSets ensure that instances are deployed and scaled in a controlled and predictable order. Network Identities: Kubernetes. What is the difference between them. DaemonSets replicate a Pod to every Node in your cluster, while StatefulSets provide persistent replica identities. The same thing can be done by using StatefulSets. Due to this issue¹ automatic rollback in case of failed upgrade is not possible. A diferencia. This is true for both deployments and statefulsets (and pods, rcs, rss jobs, etc. To create the deployment, run the following command: $ kubectl apply -f deployment. Other examples of stateful applications include MySQL clusters, Redis, Kafka, MongoDB, and others. StatefulSets use a Headless Service resource, which sets the clusterIP property to none. Currently there are several API groups in use:A StatefulSets provides a persistent identity to the pods that they create and manage. Not all stateful applications scale nicely. Using volumeClaimTemplates, each replica will get a unique PersistentVolumeClaim with statefulset whereas all replicas would share the PersistentVolumeClaim with a deployment. I'm using Logstash on Kubernetes and use the official Helm chart at this link. It provides guarantees about the ordering of deployment and scaling. Using volumeClaimTemplates, each replica will get a unique PersistentVolumeClaim with statefulset whereas all replicas would share the PersistentVolumeClaim with a deployment. Using StatefulSets to run Stateful applications at scale. They give Pods a stable identity and consistent ordering during scaling operations. “Hay otro, el ReplicationController pero Kubernetes ahora apunta a Deployment que automáticamente crea ReplicaSets”. StatefulSets Example. The Horizontal Pod Autoscaler is implemented as a Kubernetes API resource and a controller. In the previous blog we created a stateless application, deployed with K8s resource Deployment, which allows one to replicate the application, but where data is lost when Pods are restarted, meaning there were no data consistency. This chart deploys Logstash as a statefulset. 5 In the latest release, Kubernetes 1. It can appear that StatefulSet is a way to solve at most one instance in a situation with a network partition , but that is mostly in case of a stateful replicated application like e. “Hay otro, el ReplicationController pero Kubernetes ahora apunta a Deployment que automáticamente crea ReplicaSets”. Statefulsets and Operators are not that similar. You can use StatefulSets to deploy stateful applications and clustered applications that save data to persistent storage, such as Compute Engine persistent. yaml 392 kubectl apply -f pod2. I have a kubernetes cluster and I have a simple deployment for mongodb with NFS persistent volume set. 而因為有關聯，所以在Deployment下的Label Name，會同樣印在pod上。. 4. Also, you will not have to create a PVCs in advance, and you will be able to scale it easily. 2. Check the status of the Deployment using the kubectl get deployments command. February 11, 2023 by jamezshame. Let's deploy mehdb first. StatefulSets. Deployment. They function similarly to Deployments but assign a unique identifier to each Pod they encapsulate. With the clean service created, proceed to deploy it as shown below. DaemonSet vs. Similarly, the deployment script. Currently we are using a Deployment and a ReplicaSet for this. Both are related to the limited control that deployments provide over how an application runs: Lack of granular control. Although Kubernetes is best known for running applications, it's also capable of running databases. StatefulSets are used to scale-out stateful workloads since you define volumeClaimTemplates which allow the K8s Controller to replicate PVCs as you increase replicas. yaml We need to create a pvc. OF THE TALKKubernetes provides different resources for deploying applications, we will be lookin. Any application. Define a Stateful Set with PVC. I think statefulsets make sense for it. Un StatefulSet es el objeto de la API workload que se usa para gestionar aplicaciones con estado. Specifying minReadySeconds slows down a rollout of a StatefulSet, when using a. 7) uses an update strategy to configure and disable. 9 release. Al igual que un Deployment, un StatefulSet gestiona Pods que se basan en una especificación idéntica de contenedor. A ReplicaSet is used to ensure that a specific number of replicas (copies) of a pod are running at any given time, while a Deployment manages updates to a ReplicaSet by creating a new ReplicaSet with the updated pod template and gradually scaling it up while scaling down the old ReplicaSet. I have created. So yes, StatefulSet helps preserve the order and name of the pod, but what is it that it does extra (or different) that is advantageous over a regular Deployment with respect to volumes. When a StatefulSet's . 5 and becoming stable in 1. Requirements of Stateful Applications. StatefulSets: Use StatefulSets to deploy stateful applications. statefulset. 那使用Deployments更重要的是，可以方便Rollback到之前版本，而使用StatefulSets、DaemonSets. Deployment: Deployment is a built-in. Comme un Déploiement, un StatefulSet gère des Pods qui sont basés sur une même spécification de conteneur. Deployment is a resource to deploy a stateless application, if using a PVC, all replicas will be using the same Volume and none of it will have its own state. The following brings up the StatefulSet including two pods (a leader and a follower), binds the persistent volumes to each pod as well as creates a headless service for it: $ kubectl create ns mehdb. Kubernetes Deployments Vs StatefulSets. At this point we have a running MySQL server, let's use this guide to simulate failover of a node. Just make sure you have reclaimPolicy: Retain in your StorageClass definition. While this approach may be sufficient for stateless applications, the Deployment Controller isn't ideal for applications that require: A persistent naming convention or storage. Given this difference, Deployment is more suited to work with stateless applications. 27, this feature is now beta. As a result, sometimes other Kubernetes services compete with the stateful service over available resources. So by passing this flag to kubectl delete the Pods that are managed by. The deployment uses a selector to match labels defined in the pod template. It allows you to define the Kubernetes Deployment or StatefulSet that you want KEDA to scale based on a scale trigger. Kubernetes deployments manage stateless services running on your cluster (as opposed to for example StatefulSets which manage stateful services). It allows you to define the Kubernetes Deployment or StatefulSet that you want KEDA to scale based on a scale trigger. system (system) Closed March 11, 2022, 6:44am 3. Skaffold is a command line tool from Google that brings automation to the deployment workflow of Kubernetes applications. 1. metadata: annotations: # This is. As with any. Kubernetes has rich features like StatefulSets and deployment. yaml. StatefulSetCondition describes the state of a statefulset at a certain point. , pod-0, pod-1, pod-n. FYI: You had the right approach in the beginning with Deployment + PVC. 9) is a Kubernetes resource used to manage stateful applications. Like a Deployment, a StatefulSet manages Pods that are based on an identical container specification. To create the MongoDB replica set, run these two commands: kubectl apply -f googlecloud\_ssd. 6 StatefulSet vs Deployment: persistent storage; 8. As a result, running this example will require an environment based on Kubernetes 1. By deploying pods in a specific order and maintaining persistent storage, StatefulSets provide a reliable and scalable platform for running stateful. Welcome to a comprehensive journey into the heart of Kubernetes deployment strategies – StatefulSets and Stateless Deployments. When comparing a Deployment vs Replica Set, the former provides the same replication functions (through Replica Sets) and also the ability to rollout changes and roll them back if necessary. Pods are a great way for you to deploy an application, but there is some limitation to the pod resource type. Figure 3: Persistence in statefulsets as each having its own volume. [email protected] VS Deployment. yml secret/mysecret created. Remember that you can choose any namespace of your choice here. Unlike a. What problems can heppen if i deployed MySQL Database with "deployment" not "statefulset", other than backup which i already handled. As the name suggest the statefulsets are specifically used to make sure the app state is saved by each running pod. 0 with new features and enhancements is available now. Ordered, graceful deployment and scaling. StatefulSetには以下のような特徴がある。. They both consume resources and can affect overall performance. All the examples available are showing Redis cluster being deployed as a combination of Kubernetes’ StatefulSets and PersistentVolumes. Each instance is created one by one, and Kubernetes waits for each one to be up and running before proceeding to the next. 5; it consists of a bond between the pod and the Persistent Volume. Each pod has a persistent identifier, that it maintains across any. By default, statefulsets start the first, then second, then third, etc. Given this difference, Deployment is more suited to work with stateless applications. In our case it will be a MariaDB container configured as statefulset set, in stead of a deployment. Unlike a Deployment, a StatefulSet maintains a sticky identity for each of. Pricing. Kubernetes StatefulSets provide two main advantages (for stateful applications) over Deployments: a stable identity of the pods and the ability to follow specific Deployment orders. StatefulSets are Kubernetes component that is used specifically for stateful applications. It worked as expected and both the prometheus pods got restarted. 1. Get Full-Length High-Quality DevOps Tutorials for Free - Subscribe Now. Create a stateful set. StatefulSets vs. There are two primary options for deploying a database on Kubernetes: StatefulSets and custom. I have created a statefulset with 3 replicas with dynamic persistent volume claim with access mode as "Readwriteonce". This label ensures that child ReplicaSets of a Deployment do not overlap. js application to five replicas. Stable And Ordered. StatefulSet est l'objet de l'API de charge de travail utilisé pour gérer des applications avec état (stateful). A StatefulSet can deploy applications that need to reliably identify specific replicas, rollout updates in a pre-defined order, or. Step 1 - Create Kubernetes Environment. Create a StatefulSet file. In the last lesson, we skipped over the whys and wherefores of StatefulSets to focus on implementing Secrets. Una aplicación stateless es aquella que no tiene estado, a la que no le importa la red en la que se esta. That's it! With these two commands, you have launched all the components required to run an highly available and redundant MongoDB replica set. Authors: Ravi Gudimetla (Apple), Filip Křepinský (Red Hat), Maciej Szulik (Red Hat) This blog describes the two features namely minReadySeconds for StatefulSets and maxSurge for DaemonSets that SIG Apps is happy to graduate to stable in Kubernetes 1. First, let's verify that StatefulSet has created the leader ( mehdb-0) and. Suppose your deployment configuration file looks like this and you saved that in nginx. Some of the key features of StatefulSets are as follows: 1. extensions/created. Switch on the feature gate with the command line flag --feature-gates=StatefulSetMinReadySeconds=true on kube-apiserver and kube-controller-manager. Diferencia entre Statefulset y Deployment en Kubernetes. Download and install a kubectl greater than v1. Self-managed. Caching Systems: StatefulSets can be used to deploy caching systems in Kubernetes, as they provide stable network identities, persistent storage, and predictable deployment and scaling. The Kubernetes Control Plane is your cluster’s management surface. The primary idea behind StatefulSets is to allow developers to deploy applications that require data to be stored in a filesystem with the ability to re-attach to them if they restart by failure. In Kubernetes, a Deployment is a workload resource object that lets you configure the lifecycle of pods in the cluster. Share. StatefulSets maintain the state of applications beyond an individual pod lifecycle. A StatefulSet is a group of pods with persistent identities and stable hostnames, designed to run stateful and replicated Kubernetes services. But Statefulsets eliminates the previous states and data stored problems. yml service/redis-ss created. Pods in a StatefulSet will have an IP. It allows us to automate deployments, scale, and manage. We need to specify service instances to be deployed to different boxes, anti-affinity on pods, for high availability. They each have their own sticky identity, which they keep between. If ordering may become important in the future, statefulsets become the obvious route; you can replicate deployment behavior with statefulsets, but not (as easily) in the other direction. Let’s take a look at Deployments, DaemonSets, and StatefulSets. StatefulSets vs Deployments for stateless applications on Kubernetes. You may notice two things here: (1) there is only one pod created while we asked for three, and (2) the pod name contains the StatefulSet name. What is Statefulsets? A StatefulSet is a controller that helps you deploy and scale groups of Kubernetes pods. 2. While this approach may be sufficient for stateless applications, the Deployment Controller isn't ideal for applications that require: A persistent naming convention or storage. Statefulsets. It is the default strategy when . What is the difference between StatefulSet and Deployment? Ans: A StatefulSet acts as a controller in Kubernetes that manages pods just like Deployments. In case deployments is select,. Deployment. Published on Sep. When you have an app which requires persistence, you should create a stateful set instead of deployment. References: The first referred URL (k8s SS) states explicitly: StatefulSets currently require a Headless Service to be responsible for the network identity of the Pods. For example, assume you are planning to deploy your Node. They have different semantics while updating or when the pod becomes unreachable. Note: While ReplicaSets can be used, Kubernetes recommends using Deployments. kubectl create namespace database. StatefulSetCondition describes the state of a statefulset at a certain point. DaemonSets. StatefulSets manage the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods. A Kubernetes pod is a cluster deployment unit that typically contains one or more containers. However, Operators can go much further than what StatefulSets could possibly offer. StatefulSets use cases; StatefulSets are valuable for applications that require one or more of the following. Kubernetes StatefulSet simply explained | Deployment vs StatefulSet. As their name suggests,. Does it need ordered instance scale-up and scale-down? If you share what application you are using, it is easier to tell if it tolerate that the instances scale-up or. Very useful for HA workloads. The ClusterIP is only internal and provides the Kubebernetes cluster a fixed endpoint to reference your deployment/pod internally. In contrast to that, the Pods deployed by StatefulSet component are NOT identical and deployment is more complex. Deployments allow you. By far the most common way to run a database, StatefulSets is a feature fully supported as of the Kubernetes 1. 2. ReplicaSet vs. PVCs are not the only reason to use Statefulsets over Deployments. How PVC works in case of statefulsets. StatefulSet. Additionally, StatefulSets enables you to reschedule database pods to other nodes. g. To make it easier to eliminate fields or restructure resource representations, Kubernetes supports multiple API versions, each at a different API path, such as /api/v1 or /apis/extensions/v1beta1 and to extend the Kubernetes API, API groups is implemented. These can be used to make sure that a pod. To create a service, use the kubectl expose command. StatefulSetの概要. apiVersion: v1 kind: Secret metadata: name: mysecret type: Opaque data: ROOT_PASSWORD: cGFzc3dvcmQ=. Pods in StatefulSets have reliable network identities. DaemonSet vs. They both have self-healing. Published February 8, 2022. A template describes a set of objects that can be parameterized and processed to…This task shows how to scale a StatefulSet. As opposed to the Deployment, the StatefulSet creates pods directly. First sentence in the documentation: "The Horizontal Pod Autoscaler automatically scales the number of Pods in a replication controller, deployment, replica set or stateful set". 1. We will take the example of Cassandra to learn about statefulset upgrade feature. . You can delete a StatefulSet in the same way you delete other resources in Kubernetes: use the kubectl delete command, and specify the StatefulSet either by file or by name. These priorities does not only happens when a Node becomes unreachable, but at all times, e. StatefulSetではPodのSTATUSがUnknownになってもPodを自動起動しない。Kubernetes StatefulSets. StatefulSets:Initially deployment should come up with 1 replicas when 1st node is created and grow as we add more worker/master nodes to it and once max is achieved, it should stop growing. Using the Kubernetes Scheduler, the Deployment Controller runs replicas on any available node with available resources. StatefulSets provide the ability to use persistent volumes for each. One pod after another. Unlike in a standard Deployment, StatefulSets are aware that your application is stateful and will therefore treat it accordingly. Just like StatefulSets, Kubernetes Deployments let you define the state of the application, and the Deployment’s controller is responsible for maintaining this state. StatefulSets handle the deployment and scaling of sets of Kubernetes pods, providing guarantees about their uniqueness and ordering. Deployment. This will be a standalone tutorial. For hostnames, stable network identifiers please refer to the statefulset basics: For a StatefulSet with N replicas, each Pod in the StatefulSet will be assigned an integer ordinal, from 0 up through N-1, that is unique over the Set A StatefulSet can use a Headless Service to control the domain of its Pods. This is important because many stateful applications have data initialization routines to perform, masters to elect, and quorum to achieve. Kubernetes provides StatefulSets, a type of controller or workload used to deploy and run stateful applications in a Kubernetes environment. Deployment Spec vs StatefulSet Spec Deployment specs and StatefulSet specs are quite similar. StatefulSet is a workload API object designed to assist in managing stateful applications. StatefulSets maintain a sticky identity -- one that persists despite rescheduling -- for each pod and attached storage. Example. Share. Why use StatefulSets. StatefulSet. A Deployment provides the following functions: It allows you to define the. It allows us to automate deployments, scale, and manage containerized applications. To understand about Statefulset you need to know how generally database deployments. MySQL settings remain on insecure defaults to. Stateful sets are used for application storing data in memory, session and handling state. Statefulsets. kind: Service metadata: name: redis labels: app: redis spec: type: ClusterIP ports: - name: redis port: 6379 targetPort. Open this file in a code-editor and write the following code into it: apiVersion: apps/v1. Download and install a kubectl greater than v1. Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec.