EKS is best suited for AWS, so it might be the best option if you are running Kubernetes on AWS. Deployments vs Daemonsets vs Statefulsets. For example, liveness probes could catch a deadlock, where an application is running, but unable to make progress. Deploy and Manages the stateless application. For example, you define how many replicas ( pods) of your app you want to run in the deployment. Each object in your cluster has a Name that is unique for that type of resource. When it comes to Kubernetes, you can scale: 1. 每个pod都有自己存储，所以都用volumeClaimTemplates，为每个pod都生成一个自己的存储，保存自己的状态 3. This is different from a Deployment where the Pods are expected to be interchangeable. Jobs with fixed completion count - that is, jobs that have non null . This task shows how to scale a StatefulSet. Kubernetes Deployment. This tutorial provides an introduction to managing applications with StatefulSets. Apr 6, 2020 at 8:53. Access spring security through kubernetes ingress. unknown. Apr 6, 2020 at 8:53. NFS subdir external provisioner is an automatic provisioner that uses your existing and already configured NFS server to support dynamic provisioning of Kubernetes Persistent Volumes via Persistent Volume Claims. The output shows that the Deployment has two Pods. DaemonSets, StatefulSets and Deployments are three ways to deploy workloads in Kubernetes. 2. g. So, for example, Kubernetes will only create example-statefulset-5 after example-statefulset-4 is up and running. If you are unsure about whether. Deploying a. StatefulSet is the workload API object used to manage stateful applications. First, we run the service template : kubectl apply -f service. api. These pods are created from the same spec, but are not interchangeable: each has a persistent identifier that it maintains across any rescheduling. Then, the second pod (2) does likewise. Just as a node is a compute resource used by the cluster, a PV is a storage resource. Statefulsets. Identities are defined as: - Network: A single stable DNS and hostname. Unlike a Deployment, a StatefulSet has a persistent ID for each Pod that persists across any rescheduling or. The storage for a given Pod must either be provisioned by a PersistentVolume Provisioner based on the requested storage class, or pre-provisioned by an admin. DaemonSet Kubernetes has several ways to deploy applications, including deployments, DaemonSets and StatefulSets. Kubernetes administrators define classes of storage, and then pods can dynamically request the specific type of storage they need. Secrets in K8s. StatefulSet. A StatefulSet is another Kubernetes controller that manages pods just like Deployments. summary, it is possible to set min / max replicas for a statefulset using HPA. Let’s take a look at Deployments, DaemonSets, and StatefulSets. CronJob. 16. As mentioned above most of the time you can simply use volumes without the need to define StorageClass or PV/PVC. kubectl basics. Provide a name for the deployment and the container image to deploy. Let’s use the UI for our first example. Each individual deployment is represented as a replication controller. Kubernetes is a popular choice for hosting Orleans applications. Create a MySQL Deployment. In the process, Karpenter will interpret the requirements of the pods that need to be scheduled and provision nodes that allow for these affinity rules to be met in an optimal way. The generation observed by the deployment controller. Labels can be used to select objects and to find collections of objects that satisfy certain conditions. 28. 9. They use a K8S component called Service, to group the pods using labels. Using volumeClaimTemplates, each replica will get a unique PersistentVolumeClaim with statefulset whereas all replicas would share the PersistentVolumeClaim with a deployment. The application is MySQL. Kubernetes Deployments are. Here is the quote from a relevant section from the docs: Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. We are going to need the affinity/anti-affinity settings. readyReplicas integer: readyReplicas is the number of pods targeted by this Deployment with a Ready Condition. (K8S default), set the image of the container to a new version for a particular deployment. Skipping a pod deployment in statefulset. What happens when we upgrade a Statefulset to a. Let us see how StatefulSet differs from Deployment-1. A Kubernetes secret for storing the database password. g. Scaling down a Deployment removes arbitrary Pods, which could include the primary node in your database system. For example, to create and check a service configuration for an Nginx application, use the following: kubectl expose deployment/nginx-app1. Object Names and IDs. This registry. Before proceeding, make yourself familiar with the considerations. You will likely need to delete and recreate the statefulset to add a new volumeClaimTemplate. Several other StatefulSet features also apply to this example: StatefulSet vs Deployment In Kubernetes, a Deployment is a workload resource object that lets you configure the lifecycle of pods in the cluster. 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. In this article, we’ll take a look at the differences between Deployment and StatefulSet and when you. spec. For example, caching services are often limited by memory. StatefulSet 是用来管理有状态应用的工作负载 API 对象。 StatefulSet 用来管理某 Pod 集合的部署和扩缩， 并为这些 Pod 提供持久存储和持久标识符。. Dynamic volume provisioning allows storage volumes to be created on-demand. This task shows you how to delete a StatefulSet. Check. a cache or database cluster even though it may solve your specific situation as. KEDA will monitor that service and based on the events that occur it will automatically scale your resource out/in accordingly. All of the other parts are ready and we will just plug in the engine and we will be ready to hit the road. First, we run the service template : kubectl apply -f service. Kubernetes or K8s is an open-source orchestration system for containerized applications that helps in automating software deployment, management and scaling. This way you could either, name the stateful-set according to the classes, i. We explore these features using Apache ZooKeeper and Apache Kafka StatefulSets and a Prometheus node exporter. A StatefulSet is a controller that helps you deploy and scale groups of Kubernetes pods. kubectl rollout undo deployment/<deployment name> – Rollback a. StatefulSet. If we need to update the application to a new version, we can change the fields in the Deployment YAML file. In Pods under Application Workloads, you can see all the Pods are up and running. When to use a ReplicaSet. In statefulsets each replica pod. The StatefulSet, typically used to manage stateful applications, manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods. e. Pods. It doesn't necessarily refer to the deployment of applications or services. Parallel. Run a Stateless Application Using a Deployment; Run a Single-Instance Stateful Application; Run a Replicated Stateful Application; Scale a StatefulSet; Delete a. system (system) Closed March 11, 2022, 6:44am 3. StatefulSet ensures that, at any time, there is at most one Pod with a given identity running in a cluster. Unlike deployments, statefulset maintains an identity for each of the pods. Now, a lot of support is available for running stateful applications with Kubernetes. completions successfully completed Pods. StatefulSetは状態を保持する (ステートフルな)アプリケーションを管理するためのKubernetesオブジェクトだ。. apps/web scaled deepak. Offers declarative updates for pods an RS. You can use statefulsets if you want fixed pod names for your application. k8s. spec. Overview of StatefulSets. Kubernetes has become the de-facto orchestration tool and initially it was supporting stateless applications, but stateful (data-driven) applications are very common and are critical to. We like to dynamically assign a value (that's derived from the ordinal index) to the pod's label and later. In K8s, StatefulSets are a higher-level abstraction over pods that provide guarantees about the ordering and uniqueness of pods. Kubernetes package adds integration for hosting an Orleans. DaemonSet vs. also during upgrades and. 9. Introduction. Statefulset vs Deployment; StatefulSet and Deployment are both Kubernetes resources used for managing containerized applications, but they differ in their intended use cases and features. Update Deployment Strategies. I've installed these components in the k8s cluster using the mixin kube-prometheus. Introduction A StorageClass provides a way for administrators to describe the "classes" of storage they offer. 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. This ensures it’ll be postgres-2 that’s destroyed first. Since Elasticsearch maintains state, we need to use StatefulSet which is a deployment that can maintain state. If you don’t specify the namespace, it gets deployed in the default namespace. One pod should be able to reach other pods with well-defined names. Deployment. This means that the Deployment object can have as many active replica sets as possible, and eventually the deployment controller will scale down all old replica sets and scale up. StatefulSet has a lot of similar characteristics to a Deployment, and it's scaled like that, it has a pod spec like that, but it is different from Deployment. StatefulSet. When a headless Service sits in front of a StatefulSet, Kubernetes takes this one step further and allows DNS queries for the Pod name as part of the Service domain name. StatefulSets will ensure the same PersistentVolumeClaim stays bound to the same Pod throughout its lifetime. Compare Kubernetes StatefulSet vs. In a stateful containerized application, data must be persistent, retained and easy to access outside the application. Something like: apiVersion: extensions/v1beta1 kind: Deployment metadata: name: my-deployment spec: template: # Below is the podSpec. The output of the describe command in this example is the following: Name: nginx-app1. 2. The deployment is made up of 2 Nginx web servers; both of them are connected to a persistent volume. Deleting and/or scaling a StatefulSet down will not delete the volumes associated with the. StatefulSets. vim redis-statefulset. metadata. However, StatefulSet objects include a volumeClaimTemplates array, which automatically generates the PersistentVolumeClaim objects. zk-0 zk-1 zk-2See StatefulSet vs. The solution(s) : Use a StatefulSet, ReplicaSet or DaemonSet to ensure the Pod creation after a Node failure. It uses a template to describe what each Pod must contain. If we need to update the application to a new version, we can change the fields in the Deployment YAML file. Orleans will run in Kubernetes without specific configuration, however, it can also take advantage of extra knowledge which the hosting platform can provide. StatefulSet. 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. Before you begin StatefulSets are only available in Kubernetes version 1. Deployments in k8s do not keep state in their Pods by assuming the application is stateless. A DeploymentConfig (DC) in OpenShift is more or less equivalent to a Kubernetes Deployment, nowadays. Simply use a volume in the required Resources and K8S will take care of that for you. WEKA. Published Oct 5, 2022. 23 introduced a new, alpha-level policy for StatefulSets that controls the lifetime of PersistentVolumeClaims (PVCs) generated from the StatefulSet spec template for cases when they should be deleted automatically when the StatefulSet is deleted or pods in the StatefulSet are scaled. Each Pod has init and main container. Every Kubernetes object also has a UID that is unique across your whole cluster. yaml. We need to specify service instances to be deployed to different boxes, anti-affinity on pods, for high availability. This task shows how to scale a StatefulSet. The spec matches the StatefulSet to the Headless Service using a selector that matches the labels. Yes, Statefulset is the way to go if the pods need to have their identity defined in some way. They both make it easy to orchestrate multiple Pod replicas, but they have different features that specialize them for separate use cases. The manifest files do not have the namespace added to them. The answer is in your first log: The StatefulSet "cassandra" is invalid: spec: Forbidden: updates to statefulset spec for fields other than 'replicas', 'template', and 'updateStrategy'. Storage classes can define properties of storage systems. Can support many different deployment patterns, including full restart, customizable rolling updates, and fully custom behaviors, as well as pre- and post- deployment hooks. Editor's note: today's post is by Janet Kuo and Kenneth Owens, Software Engineers at Google. Create a new file and fill it with the following StatefulSet configuration then we explain what it does. The differences in this manifest are: Using kind: Deployment to state the resource type. You can use kubectl create configmap with the --from-literal argument to define a literal value from the command line: kubectl create configmap special-config --from-literal=special. It is clearly explained in the documentation under Deleting the Statefulset: Deleting a StatefulSet through kubectl will scale it down to 0, thereby deleting all pods that are a part of it. En esta entrada vamos a tratar sobre aplicaciones Stateful en Kubernetes – Statefulset, el cual es un tipo de recurso que nos ofrece Kubernetes. A Kubernetes Deployment YAML specifies the configuration for a Deployment object—this is a Kubernetes object that can create and update a set of identical pods. The response should be similar to: NAME READY STATUS RESTARTS AGE cassandra-0 1/1 Running 0 1m cassandra-1 0/1. StatefulSetには以下のような特徴がある。. In this. moury~ % kubectl scale statefulset web --replicas=3 statefulset. How to Set Up a Kubernetes MySQL Deployment with Cloud Volumes ONTAP. Manages the deployment and scaling of a set of Pods, and provides. In contrast, annotations are not used to identify and select objects. It manages the deployment and scaling of a set of Pods, and provides guarantee about. Name Stays the Same. So, for example, Kubernetes will only create example-statefulset-5 after example-statefulset-4 is up and running. Deployment では、全てのPodで1個のPV をマウントしている違いがあります. StatefulSets also enforce that Pods are removed in reverse order of their creation. StatefulSets let you run stateful applications in Kubernetes. The StatefulSet will not even scale until all the required pods are running, so if one dies, it recreates the pod before. As a result, when the deployment starts to scale, unready applications might receive traffic. StatefulSet(stable-GA in k8s v1. StatefulSets are particularly useful when you have stateful applications, such as databases, that require stable network identities and persistent storage. StatefulSets handle the deployment and scaling of sets of Kubernetes pods, providing guarantees about their uniqueness and ordering. The reference to the resource this ScaledObject is configured for. Furthermore, StatefulSet comes with the capability of running replicas with stable DNS name/entries that target each replica. Các Pod của Statefuleset không hoàn toàn giống. This document describes the concept of a StorageClass in Kubernetes. func NewForConfigAndClient (c * rest. kubectl apply -f <name> to recreate the StatefulSet. You should use a HorizontalPodAutoscaler (HPA for short): HPA automatically updates a workload resource (such as a Deployment or StatefulSet), with the aim of automatically scaling the workload to match demand. spec: serviceAccountName: build. 0. k8s. kubectl apply -f <name> to recreate the StatefulSet. Note that you must manually create 3 deployments as you can't have a service point to a single pod in a deployment. This application is a replicated MySQL database. Then we run the command for the deployment template : kubectl apply -f demo-deployment. To check the image deployed on these Pods, use the describe pods subcommand: kubectl describe pods. On deployment level it is not possible, but there is an option to do this indirectly. 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. A Deployment manages multiple pods by automating the creation, updating, and deletion of ReplicaSets. Although this is not directly answer your question, maybe it provides some hint for your consideration. We are now in the interesting part of this meal. StatefulSet. yml2 Answers. Kubernetes deployments manage stateless services running on your cluster (as opposed to for example StatefulSets which manage stateful services). If you look at web_stateful. The most basic difference is that you would get ability to persist pod level state with statefulsets. StatefulSetCondition] You should delete everything from the status field. affinity. The StatefulSet resource deploys Pods sequentially. We are going to take a deeper dive into Blue/Green as well as two more deployment strategies: Canary and A/B Testing. In Kubernetes, a Service is a method for exposing a network application that is running as one or more Pods in your cluster. The most basic difference is that you would get ability to persist pod level state with statefulsets. This page shows how to delete Pods which are part of a stateful set, and explains the considerations to keep in mind when doing so. Deploying the Headless Service and. there are a few things you can do with a DeploymentConfig (around triggers) that you can't do. Manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods. StatefulSets are designed to run stateful applications in Kubernetes with dedicated persistent storage. A key aim of Services in Kubernetes is that you don't need to modify your existing application to use an unfamiliar service discovery mechanism. 安定したネットワーク識別子. Login to the MySQL pod and Verify: kubectl exec -it mysql-0 -- mysql -u root -p. yaml kubectl apply -f mongo-statefulset. PersistentVolumes. Kubernetes is a powerful container orchestration tool that provides a variety of resources. 9) is a Kubernetes resource used to manage stateful applications. Kubernetes (K8s) is one of the popular open-source container orchestration systems for automating deployment, scaling, and management of containerized applications. Statefulsets is used for Stateful applications, each. Use multiple nodes. This is great for stateless apps that we want online, ASAP. e: class-name and the pod created will be class-name-0 and you can replace the _ by -. Since the two are packaged in mongo-statefulset. Implementando en Kubernetes: Deployment vs StatefulSet vs DaemonSet. 14, Kubectl also supports the management of Kubernetes objects using a kustomization file. yml. Persistent storage: Kubernetes StatefulSet can manage the creation and deletion of PVCs while Deployment can’t. deployment vs. The deployment is made up of 2 Nginx web servers; both of them are connected to a persistent volume. StatefulSets. Deployment. io. You can also use a preexisting disk in a StatefulSet. Of course, the scaling depends on the app you are deploying. Share. StatefulSet. Before you begin Before you begin this tutorial, you should familiarize yourself with the following Kubernetes concepts: Pods Cluster DNS Headless Services. Currently the StatefulSets support only two kinds of update strategies:. k8s. This logic is mandatory in. Each new pod in statefulset then have a new PV attached to them to. kubectl rollout restart sts <name> to restart the pods, one at a time. PersistentVolumes. Each pod runs specific containers, which are defined in the spec. Deployments with three replicas all schedule simultaneously. The Pods would be named kafka-0, kafka-1, and. Un StatefulSet es el objeto de la API workload que se usa para gestionar aplicaciones con estado. Now, before going to the differences, say that you try to create a Deployment of a database. nodeAffinity field (if specified) is taken into consideration by the DaemonSet controller when evaluating the eligible nodes, but is replaced on the created Pod with the node. ; A Persistent Volume (PV) to allocate storage space for the database. The common format of a kubectl command is: kubectl action resource This performs the specified action (like create, describe or delete) on the specified resource (like node or deployment). Not all stateful applications scale nicely. Deleting a StatefulSet You can delete a StatefulSet in the same way you delete other resources in Kubernetes: use the kubectl delete command, and specify the StatefulSet. In other words, each Pod completion is. The setup is also scalable. pod名字始终是固定的 4. Using ConfigMap in StatefulSet. It specifies that there should be three replicas of the Deployment and that each pod should be labeled with app: nginx. Let’s now create the Deployment using the kubectl apply command: $ kubectl apply -f deployment. In Kubernetes, a Service is a method for exposing a network application that is running as one or more Pods in your cluster. spec. The 1/1 indicates that each Pod has one container:. Kustomize is a standalone tool to customize Kubernetes objects through a kustomization file. The stable hostname is used to maintain a. This page shows how to delete Pods which are part of a stateful set, and explains the considerations to keep in mind when doing so. Deploy Elasticsearch. Like a Deployment, a StatefulSet manages Pods based on an identical container specification. Config, h * Client) (* AppsV1Client, error) NewForConfigAndClient creates a new AppsV1Client for the given config and client. When we scale the StatefulSet from 1 replica to 3, the StatefulSet controller starts to incrementally deploy new (missing) pods, one at a time. For example, if you have 3 nodes, it will schedule 3. if the node becomes unreachable (e. This is different from vertical scaling, which for Kubernetes would. This name will become the basis for the ReplicaSets and Pods which are created later. Manages the deployment and scaling of a set of Pods , and provides guarantees about the ordering and uniqueness of these Pods. Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. apps/mongo created Click Check my progress to verify the objective. Note the client provided takes precedence over the configured transport values. StatefulSet. Get the Pods to see the ordered creation status: kubectl get pods -l="app=cassandra". requires writes. You can also update the object's resource requests and limits, labels, and annotations. There are many benefits. We want to deploy service sets to machine "areas" so that services are running close to resources they manage. Define the application in YAML format using kind: StatefulSet. - Storage: As many VolumeClaims as requested. Deploymentと異なり、StatefulSetはPodを直接管理しています。 OrderedReadyはReadinessProbeを監視しつつ、一つずつPodを増減します。 ParallelはDeploymentのスケールと同様、Podを並列的に増減させます。 Podの更新. When a pod instance managed by a StatefulSet disappears (because the node the pod was running on has failed, it was evicted from the node, or someone deleted the pod object manually), the StatefulSet makes sure it’s. February 4, 2021. 3. These pods are created from the same specification, but they are not interchangeable: each one has a persistent identifier maintained across any. There were no major changes to the API Object, other than the community selected name, but we added the semantics of “at most one pod per index” for deployment of the Pods in. For example, an application that writes logs to Persistent Volume claim (PVC) in K8s could be considered as stateless even using storage. kubectl basics. statefulset. 2. The termination of Pods is performed in reverse {N-1. Conclusion. Storage for. MySQL Deployment on Kubernetes. StatefulSet is also a Controller but unlike Deployments, it doesn’t create ReplicaSet rather itself. Deployment: Pods have an ID that contains the. Understanding ReplicaSetsIt will trigger them all at once. The first method will store users in one file and passwords in another file, and create the Secret object by reading from files. yml Statefulset . Storage. This page shows how to run a replicated stateful application using a StatefulSet. If you want to provide workload persistence using Kubernetes persistent storage, you can incorporate a StatefulSet into your. Each Pod in the StatefulSet gets a name generated by suffixing the pod ordinal to the StatefulSet name. Deployment vs Statefulset. Scaling Down. Statefulset es un recurso que controla y gestiona en kubernetes uno o más Pods, pero entonces por qué no usar un Deployment te estarás preguntando?, entonces antes de continuar es mejor. While they have similar goals, they handle them in very different ways. In a production. 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. Deployment では、全てのPodで1個のPV をマウントしている違いがあります. Before diving in, let’s have a look at the main differences: Deployment. If there's heavy load, you can set up a HorizontalPodAutoscaler to. The above command will create a ReplicaSet with three replicas and manage the lifecycle of the pods. When pods run as part of a StatefulSet, Kubernetes keeps state data in the persistent storage volumes of the StatefulSet, even if the pods shut down. The StatefulSet name is derived from the Elasticsearch resource name and the NodeSet name. e. spec. First, the (1) pod comes up, initialized, and then settles into a “ready” state. The last section of the manifest defines our StatefulSet. Following the same logic, if something happens to any of the pods, it will be recreated with the same name. Each Pod in a StatefulSet derives its hostname from the name of the StatefulSet and the ordinal of the Pod. In one terminal, watch the StatefulSet's Pods: Yes, Statefulset is the way to go if the pods need to have their identity defined in some way. metadata: name:. You can also run EKS on Outposts for on. Before you begin This is a fairly advanced task and has the potential to violate some of the properties inherent to StatefulSet. The first line of this snippet copies the original StatefulSet and creates a statefulSetCanary, which has some additional adjustments, like the `-canary` suffix, the `track: canary` label, and. イメージ的にはPodTemplateを持つDeploymentにPVCも追加した感じ。. At this point we have a running MySQL server, let's use this guide to simulate failover of a node. podManagementPolicy. If the StatefulSet is scaled down to one replica, mysql-3 is guaranteed to exit first, followed by mysql-2. When using Kubernetes, most of the time you don’t care how your pods are scheduled, but sometimes you care that pods are deployed in order, that they have a persistent storage volume, or that they have a unique, stable network identifier across. The actual Pod creation is handled by the StatefulSet controller in Kubernetes. The deployment pod remains for an indefinite amount of time after it completes the deployment in order to retain its logs of the deployment. The list of stateful charts using a StatefulSet: $ git grep -li 'kind: *StatefulSet' | awk -F '/' '{print $1}' cockroachdb concourse consul ipfs memcached minio mongodb-replicaset rethinkdbkubectl create -f ssd-storageclass. 3. StatefulSetの概要. Kubernetes Deployment vs. En esta entrada vamos a tratar sobre aplicaciones Stateful en Kubernetes – Statefulset, el cual es un tipo de recurso que nos ofrece Kubernetes. Authors: Mahamed Ali (Rackspace Technology) The Kubernetes project runs a community-owned image registry called registry. Familiarity with volumes and persistent volumes is suggested. apps. DeploymentはRollingUpdateとParallelの2つのストラテジーがあります。Instead of using a nodeAffinity in the PVC definition, I suggest using an podAntiAffinity rule in the statefulset definition to deploy your application so that no two instances are located on the same host. In the above example, a StatefulSet named "my-statefulset" is created with three replicas. In this cheatsheet, we will take a look at. kubectl delete sts --cascade=orphan <name> to delete the StatefulSet and leave its pods. apps is the apiGroup for the deployment resource. yaml, we can run the following command to run both of them: kubectl apply -f mongo-statefulset. If you define args, but do not define a command, the default command is used with your new arguments. Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. One pod should be able to reach other pods with well-defined names. Kubernetes (K8s) es un orquestador de contenedores de código abierto orientado a automatizar la implementación, escalado y administración de aplicaciones en contenedores Docker o CRI-O. This is required by RabbitMQ for clustering, and as mentioned in the Kubernetes documentation, has to be created before the Stateful Set. DaemonSet Kubernetes has several ways to deploy applications, including deployments, DaemonSets and StatefulSets. Kubernetes administrators define classes of storage, and then pods can dynamically request the specific type of storage they need. Each time a deployment is triggered, whether manually or automatically, a deployer pod manages the deployment (including scaling down the old replication controller, scaling up the new one, and running hooks). Scaling a StatefulSet refers to increasing or decreasing the number of replicas. 15）不支持这一属性，只有StatefulSet才有，因此不得不使用后者。. The above command will create a ReplicaSet with three replicas and manage the lifecycle of the pods. Four Pods are running. Continue reading "Create statefulset MariaDB application in K8s" A StatefulSet is another Kubernetes controller that manages pods just like Deployments. But what is the best for this case ? 1 Answer. PersistentVolumes and StatefulSets are the main approaches for running stateful applications in Kubernetes. It will create three replicas in random order with a random hash. In a stateful containerized application, data must be persistent, retained and easy to access outside the application.