Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. To update a StatefulSet, you can use kubectl, the Kubernetes API, or the GKE Workloads menu in the Google Cloud console. When you revert the deployment of an upgraded binary version, the rollout process is reversed and a new set of Pods is deployed with the previous image version. The StatefulSet manifest should feel familiar—it looks a lot like a Deployment manifest! Instead of the volume field under a Deployment’s template spec, we define a VolumeClaimTemplate under the overall StatefulSet spec to describe how the workload will consume storage. If you want to delete just the StatefulSet and not the pods, use --cascade=false. Podname and Identity. Yes, Statefulset is the way to go if the pods need to have their identity defined in some way. Scaling a StatefulSet refers to increasing or decreasing the number of replicas. yml. All three of these are defined via YAML configuration. yaml kubectl get statefulset kubectl get pods. Quick tutorial #2: Creating an NFS Persistent Volume. The naming convention, network names, and storage persist as replicas are rescheduled with a StatefulSet. Deploymentなど、StatefulSet以外のリソースを使う必要がある。Author: Matthew Cary (Google) Kubernetes v1. A HorizontalPodAutoscaler (HPA for short) automatically updates a workload resource (such as a Deployment or StatefulSet), with the aim of automatically scaling the workload to match demand. The StatefulSet controller provides each Pod with a unique hostname based on its ordinal index. 1 Like. This tutorial provides an introduction to managing applications with StatefulSets . Before going for statefulset we should understand the concept of stateful and stateless applications Yes, Statefulset is the way to go if the pods need to have their identity defined in some way. A DaemonSet is a unique kind of resource that K8s assigns to a pod for each Kubernetes node in the cluster. Kubernetes Deployment vs. Identities are defined as: - Network: A single stable DNS and hostname. StatefulSet is the workload API object used to manage stateful applications. DaemonSet vs. If we need to update the application to a new version, we can change the fields in the Deployment YAML file. status. Kubernetes provides a basic resource called Pod. This behavior doesn't apply when the entire StatefulSet is deleted and can be disabled by setting a StatefulSet's . Once you’ve defined and deployed a Deployment, Kubernetes ensures that the pods it manages meet the requirements you’ve set. StatefulSet vs Deployment. using ClusterIP services). It makes sense also as each Redis instance relies on a configuration file that keeps track of other cluster instances and their roles. In contrast, annotations are not used to identify and select objects. Hi sure, that's why I noted at the end of the video that k8s supports you in that but, data synch, cloning config and storage management is. k8s components on Master vs Worker node. A Kubernetes pod is a cluster deployment unit that typically contains one or more containers. cluster. Waypoint polls the Git repository for changes and performs the steps present in the waypoint. But what is the best for this case ? This Pod is stateful (I am using volume hostPath to keep the data) and is deployed using nodeSelector to keep it always on the same Node. Deleting and/or scaling a StatefulSet down will not delete the volumes associated with the. It's created after deployment. If you use volumeClaimTemplates in StatefulSet k8s will do dynamic provisioning & create one PVC and corresponding PV for each pod, so each one of them gets their own storage. For mysql i am using statefulset and the code is here: apiVersion: apps/v1 kind:Both solutions are valid but are useful for different scenarios. Deployments and ReplicationControllers are meant for stateless usage and are rather lightweight. After reading thru Kubernetes documents like this, deployment, service and this I still do not have a clear idea what the purpose of service is. This document describes the concept of a StorageClass in Kubernetes. Oct 12, 2020 Deployments vs StatefulSets in Kubernetes Deployments vs StatefulSets TL;DR Deployments are usually used for stateless applications while StatefulSets are. also during upgrades and deployments. Each individual deployment is represented as a replication controller. Four Pods are running. As with StatefulSet creation, the StatefulSet controller created each Pod sequentially with respect to its ordinal index, and it waited for each Pod's predecessor to be Running and Ready before launching the subsequent Pod. Only stateless services should be deployed as Deployment. 7 Answers. If you look at web_stateful. field to . By default, Kubernetes uses the. If you want to provide workload persistence using Kubernetes persistent storage, you can incorporate a StatefulSet into your. ReplicaSet ReplicaSet 的目的是维护指定数量的 Pod，常用做保障指定数量 Pod 的可用性 Deployment Deployment 是一个用来管理 ReplicaSet 的更高级概念，某种程度上我们不应该操作 ReplicaSet，而是直接使用 Deployment。Deployment 拥有 Rollout & Rollback 功能，方便我们管理。 StatefulSet StatefulSet 用来管理有状态的应用，其会. First, we will create a persistent volume claim for the storage we need. –ValidationError(StatefulSet. Kubernetes StatefulSet is the workload API object used to manage stateful applications. The stable hostname is generated from the name of the StatefulSet and the ordinal number of the pod in the set. Create a file called redis-sts. Examples of replicas are. The 1. StatefulSet est l'objet de l'API de charge de travail utilisé pour gérer des applications avec état (stateful). DaemonSets. Deployment. The controller plugin is deployed as either a Deployment or a StatefulSet and can be mounted on any node within the cluster. Therefore the StatefulSet controller creates three Pods with their hostnames set to zookeeper-0, zookeeper-1, and zookeeper-3. Kubernetes headless service is a Kubernetes service that does not assign an IP address to itself. you need to create a StatefulSet configuration file that deploys the desired number of. Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. Conclusion. Kubernetes assigns every Pod a QoS class based on the resource requests and limits of its component Containers. Different classes might map to quality-of-service levels, or to backup policies, or to arbitrary. To deploy the PostgreSQL cluster, we will create a dedicated namespace named database. Of course, the scaling depends on the app you are deploying. As a pod can have one or more containers. Storage for. StatefulSets vs. This ensures it’ll be postgres-2 that’s destroyed first. The reference to the resource this ScaledObject is configured for. 10 and configured the default namespace to enable 1. A good example of an application that could use a Deployment is a web server or a microservice. Các Pod của Statefulset không thể được tạo hay xóa cùng lúc. Moreover, if at any point one of the replicas fails to start, the whole process will stop. 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。. Step-3: Creating the Secret. Storage classes can define properties of storage systems such as: How to run stateful applications in Kubernetes. As of Kubernetes v1. How Do Kubernetes Deployment and StatefulSets Work? Deployment. DaemonSets are great for running a single instance of an application on every node in the cluster. 5 In the latest release, Kubernetes 1. But still for the alertmanager statefulset, only 1 pod is getting restarted. e. The name of an Ingress object must be a valid DNS subdomain name. Although this is not directly answer your. When you apply this configuration in your cluster, an object is created, which is then managed by the relevant Kubernetes controller. e. For general information about working with config files, see deploying applications, configuring containers, managing resources. replicas is not equal to status. Nodes. 之所以要指定一个headlessService，是因为admin可以给StatefulSet创建多个、多种类型的service，k8s不知道要用哪个service的名称当作集群内域名的一部分。 Deployment类型则不能有此参数，否则报错。StatefulSets manage the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of those Pods. Comme un Déploiement, un StatefulSet gère des Pods qui sont basés sur une même spécification de conteneur. In most cases, users ignore how their pods are scheduled. Kubernetes Storage allows containerized applications to access storage resources seamlessly, without being aware of the containers consuming the data. gcr. One of the ways Kubernetes allows applications to access storage is the standard Network File Service (NFS) protocol. Understanding ReplicaSetsTo execute our deployment, we need a service to access the above deployment. It will trigger them all at once. The following provides an example of deploying a single Kubernetes MySQL instance using Trident. With this alpha feature, Kubernetes allows you to restrict volume access to a single pod. It manages the deployment and scaling of a set of Pods, and provides guarantee about. In this article: What are Kubernetes Volumes and how they work with NFS. Related Resources. From there, the StatefulSet Controller handles the. I'm using Logstash on Kubernetes and use the official Helm chart at this link. How to Use kubectl rollout restart. One pod should be able to reach other pods with well-defined names. A testing group then utilizes these back doors to confirm the Blue pods pass validation. Statefulsets, on the other hand, are useful when running workloads that require persistent storage. StatefulSet and Deployment both aim to maximise availability, however StatefulSet is constrained by its inability to. A ReplicaSet (RS) is a Kubernetes object used to maintain a stable set of replicated pods running within a cluster at any given time. If you are unsure about whether. podManagementPolicy. This page shows you how to run a single-instance stateful application in Kubernetes using a PersistentVolume and a Deployment. I was playing with k8s deployment - rolling update and it works really well. StatefulSet is a Kubernetes API object that helps in the deployment and. For example, to create and check a service configuration for an Nginx application, use the following: kubectl expose deployment/nginx-app1. Like a Deployment, a StatefulSet manages Pods based on an identical container specification. 9) is a Kubernetes resource used to manage stateful applications. This is where PersistentVolumes come into. Deployment is a specialized term in the context of Kubernetes. Connect and share knowledge within a single location that is structured and easy to search. Deployment Consistency. We are going to take a deeper dive into Blue/Green as well as two more deployment strategies: Canary and A/B Testing. Ordering: Kubernetes StatefulSet ensures that each pod is created in a specific order, while Deployment does not. The Deployment is once again using a stable. In the same blog we used PersistentVolumeClaim for dynamic provisioning of PersistentVolume, but we used. Let’s look at the StatefulSet, step-by-step. Run a Stateless Application Using a Deployment; Run a Single-Instance Stateful Application; Run a Replicated Stateful Application; Scale a StatefulSet; Delete a StatefulSet; Force Delete StatefulSet Pods; Horizontal Pod Autoscaling; HorizontalPodAutoscaler Walkthrough; Specifying a Disruption Budget for your. kubectl create -f ssd-storageclass. g. 1 Answer. Introduction A StorageClass provides a way for administrators to describe the "classes" of storage they offer. 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 restarts. Let’s rolling restart the ZooKeeper StatefulSet to update the pods to use the new version of the sidecar proxy: $ kubectl rollout restart statefulset my-release-zookeeper. I have a cluster on gke with apache, mysql and keyrock and i would like to scale it up with horizontal pod autoscaler. StatefulSets handle the deployment and scaling of sets of Kubernetes pods, providing guarantees about their uniqueness and ordering. StatefulSet - manages/maintains stable hostname, network ID and persistent storage. Kubernetes deployments manage stateless services running on your cluster (as opposed to for example StatefulSets which manage stateful services). However, by defining a Deployment object, you can specify that Kubernetes should run multiple instances of the pod. Replicas in a StatefulSet follow a graceful, sequential approach to deployment, scale, upgrade, and termination. 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. As a pod can have. A StatefulSet is a controller that helps you deploy and scale groups of Kubernetes pods. In this article. So we will add the namespace while deploying each component. Developed by Google, it's now maintained by the Cloud Native Computing Foundation. Deployment; ReplicaSet; StatefulSet; DaemonSet; etc; From the Google Search, I found out that there are K8s Operators such. com StatefulSet is the workload API object used to manage stateful applications. Apache Spark is a stateful service, those should be deployed as StatefulSet. Deployments allow you to manage sets of identical pods (or ReplicaSets) using common configurations. On an update the existing Pods will get deleted and recreated. StatefulSet is a Kubernetes controller used to deploy stateful apps. Specifying minReadySeconds slows down a rollout of a StatefulSet, when using a RollingUpdate value in . This is the resource KEDA will scale up/down and setup an HPA for, based on the triggers defined in triggers:. zk-0 zk-1 zk-26. Logs stored persistently in storage, don't represent the state of the application. NetApp Trident is a dynamic container storage interface (CSI) for use in Kubernetes. Name Stays the Same. kubectl describe svc nginx-app1. Let’s now create the Deployment using the kubectl apply command: $ kubectl apply -f deployment. E. your peers. The solution(s) : Use a StatefulSet, ReplicaSet or DaemonSet to ensure the Pod creation after a Node failure. It is important to remember that you cannot set requests that are larger than resources provided by your nodes. Kubernetes administrators define classes of storage, and then pods can dynamically request the specific type of storage they need. The Horizontal Pod Autoscaler automatically scales the number of pods in a replication controller, deployment, replica set or stateful set based on observed CPU utilization (or, with custom metrics support, on some other application-provided metrics). First, find the StatefulSet you want to scale. You can use statefulsets if you want fixed pod names for your application. StatefulSet is the workload API object used to manage stateful applications. K8s is a notoriously complex system to use and maintain, so getting a good grasp of what you should and should not be doing, and knowing what is possible will get your deployment off to a solid start. It is an ordered and graceful deployment. StatefulSetCondition] You should delete everything from the status field. As the name suggest the statefulsets are specifically used to make sure the app state is saved by each running pod. Since mongo is a database and I am using node selector, Is there any reason for me not to use k8s deployment over StatefulSet? Elaborate more on this if. Overview of StatefulSets. A single deployment configuration is usually analogous to a single micro-service. Hi keycloak community, the keycloak operator currently creates the workloads as deployment which means that the pods are replaced by a new ones when they are restarted. Furthermore assigning more CPU requests to a pod does not automatically mean that the container/application will. Deployments have two main disadvantages compared with StatefulSets and DaemonSets. By baking K8s. Applications that are stateless follow the Twelve Factor App principles. Making an app stateless make it much easier to run as a distributed system e. Choosing the right workload deployment type doesn't affect performance, but the StatefulSet does provide identity stickiness requirements. This page provides an overview of init containers: specialized containers that run before app containers in a Pod. Pods created by a StatefulSet have predictable names (and hostnames), unlike those created by a ReplicaSet . It can manage the scaling and deployment of a collection of. This controller runs Jobs -- components of a Kubernetes workload that execute specific tasks -- according to. You should read about Kubernetes autoscaling - HPA. When a StatefulSet's . They each have their own sticky identity, which they keep between. If you set CPU requests = 1 for every workload there will be no more capacity soon to schedule new pods. apps/mongo created Click Check my progress to verify the objective. PersistentVolumes and StatefulSets are the main approaches for running stateful applications in Kubernetes. kubectl get deployment – List one or more deployments. This cheatsheet will serve as a quick reference to make commands on many common Kubernetes components and. Then we run the command for the deployment template : kubectl apply -f demo-deployment. To run a Redis cluster on Kubernetes we will use a StatefulSet. 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. kubectl basics. Many different settings impact Kubernetes API security, requiring significant knowledge to implement correctly. Deployment is best suited for stateless applications while StatefulSet is best suited for. conditions[1): unknown field "lastUpdateTime" in io. Kubernetes Deployments are. PersistentVolumes. io. I've installed these components in the k8s cluster using the mixin kube-prometheus. So, to create a dummy deployment we use: bash. selector; the same selector goes into the PDBs . Các Pod của Deployment cũng có thể bị xóa theo thứ tự bất kỳ, hoặc xóa đồng thời nhiều Pod (trong trường hợp scale down deployment) Statefulset. conditions[1): unknown field "lastUpdateTime" in io. Use-cases: Daemonset vs StatefulSet. N-1} order for a StatefulSet of N-replicas. Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. Minikube is a tool used to run a single-node Kubernetes cluster locally. spec. Since the two are packaged in mongo-statefulset. Encode Decode. Pods (and, by extension, containers) are, nevertheless, short-lived entities. The Deployment creates a ReplicaSet that creates three replicated Pods, indicated by the. 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. g. If it replaces them because the configuration changes, it keeps the names the same. Each Pod in a StatefulSet derives its hostname from the name of the StatefulSet and the ordinal of the Pod. 2. At Sematext, we’re using the StatefulSet approach, which works great for us. 1. Deployment vs. Also, you will not have to create a PVCs in advance, and you will be able to scale it easily. In this example, you’ll create a deployment resource with a podAffinity rule that requires scheduling the pods on nodes in the same AZ (availability zone). It specifies that there should be three replicas of the Deployment and that each pod should be labeled with app: nginx. yaml storageclass. Kubernetes administrators define classes of storage, and then pods can dynamically request the specific type of storage they need. They use a K8S component called Service, to group the pods using labels. Deployment. Do the traffic switch. But unlike a regular deployment, it allows you to specify the order and dependencies of the deployment to. Ordinals can start from arbitrary non-negative numbers. 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. 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. Deploying the Headless Service and. g. kubectl create namespace database. StatefulSets and DaemonSets StatefulSets . StatefulSets. But however, before statefulsets were introduced into k8s many of our database applications were deployed using PVC, it also has lot of overhead. Deployments vs Daemonsets vs Statefulsets. This is great for stateless apps that we want online, ASAP. v1. Read more: Kubernetes StatefulSet: A Practical Guide. Deploying a. To ensure high availability of the application, we need to maximize the uptime of the core PHP application, the underlying storage layer backing the file system, and the. In a stateful set, pods get ID in increasing order, and this ID sticks with the pod. io/v1 metadata: name: gp2-retain annotations: provisioner: kubernetes. You can add these custom entries with the HostAliases field in PodSpec. Define a Stateful Set with PVC. mourya ~ % kubectl get statefulset NAME READY AGE web 3/3 68s. Kubernetes Apply. In a stateful containerized application, data must be persistent, retained and easy to access outside the application. status. Both Deployment and StatefulSet try to maximize the availability - but StatefulSet cannot sacrifice data consistency (e. StatefulSet. yaml. g. Once you’ve defined and. First, let's verify that StatefulSet has created the leader ( mehdb-0) and. KEDA will monitor that service and based on the events that occur it will automatically scale your resource out/in accordingly. The thermostat acts to bring the. pod. For example, if you have 3 nodes, it will schedule 3. Deploy and Manages the stateless application. Each StatefulSet domain will work as a DNS subdomain depending on the configuration of DNS for a Cluster. Unlike a. All the examples available are showing Redis cluster being deployed as a combination of Kubernetes’ StatefulSets and PersistentVolumes. 2) you configure your Deployment component to use that secret using a specific imagePullSecrets attribute. I'm using Logstash on Kubernetes and use the official Helm chart at this link. Otherwise you can use Deployments with multiple pods online for your shards. Rolling Update Strategy. The following provides an example of deploying a single Kubernetes MySQL instance using Trident. Even when there is a new rolling update, the statefulset still in the same state CrashLoopBackOff from the old rolling update. Last State: Terminated Reason: OOMKilled Exit Code: 137. The number of required nodes of our cluster. En esta entrada vamos a tratar sobre aplicaciones Stateful en Kubernetes – Statefulset, el cual es un tipo de recurso que nos ofrece Kubernetes. g. A StatefulSet is a Kubernetes API object for managing stateful application workloads. This contains fields that maybe updated both. Gestiona el despliegue y escalado de un conjunto de Pods, y garantiza el orden y unicidad de dichos Pods. In this case, you can create “headless” services by specifying. Before proceeding, make yourself familiar with the considerations. It makes sense also as each Redis instance relies on a configuration file that keeps track of other cluster instances and their roles. Because the replicas field of the nacos StatefulSet is set to 2, In the cluster file only two nacos address. Unlike a Deployment, a StatefulSet maintains a. apps. When we scale the StatefulSet from 1 replica to 3, the StatefulSet controller starts to incrementally deploy new (missing) pods, one at a time. Example-1: Using allowedCapabilities in Pod Security Policy. It will trigger them all at once. When we scale the StatefulSet from 1 replica to 3, the StatefulSet controller starts to incrementally deploy new (missing) pods, one at a time. A security context defines privilege and access control settings for a Pod or Container. I see many examples of master/slave setup for databases as a use case for StatefulSet, but can't that problem be solved with just a Deployment (replicas=1) for the master and a. Deploymentなど、StatefulSet以外のリソースを使う必要がある。1. I am curious to know how to do deployment when we have a service dependency!. Nota: Los StatefulSets son estables (GA) en la versión 1. A StatefulSets are Kubernetes objects used to consistently deploy stateful application components. StatefulSetではこれを防ぐために、kubeletが落ちても新たにPodの自動起動をしない。 言い換えると、Podを手動で削除しない限り、新たなPodは起動されない。 Podを自動で起動してほしい場合. In your case each deployment is having same PersistentVolumeClaim (that is ReadWriteOnly and can't be mounted on second request), while with volumeClaimTemplates you get different one provisioned per. The above command will create a ReplicaSet with three replicas and manage the lifecycle of the pods. apiVersion. Deployments Deployment is the easiest and most used resource for deploying an application. yaml. If you think of something that is not on this list but might be useful to others, please don't hesitate to file an issue or submit a PR. This would create a new YML file with following content (I will remove the highlighted content as those are not required at the moment): bash. We’re rapidly growing and always welcome new contributors. Deployment and ReplicaSet (replacing the legacy resource ReplicationController). Check. DaemonSets. This comes at a cost of slow scale ups and. Use kubectl to scale StatefulSets; kubectl scale sts nacos --replicas=3Deployment. Unlike a Deployment, a StatefulSet has a persistent ID for each Pod that persists across any rescheduling or. moury~ % kubectl scale statefulset web --replicas=3 statefulset. Statefulset vs Deployment in k8s. Unlike a Deployment, a StatefulSet maintains a sticky, persistent identity for each of their Pods. Updated on: April 19, 2023 Sarav AK. 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. StatefulSet Deployments provide: Stable, unique network identifiers: Each pod in a StatefulSet is given a hostname that is based on the application name and increment. v1. spec. Statefulset is generally used with a distributed applications that require each node to have a persistent state and the ability to configure an arbitrary number of nodes. The list of controller in the Control-Plane:. There was…Introduction. Define the application in YAML format using kind: StatefulSet. As I understand the purpose of the Kubernetes Controller is to make sure that current state is equal to the desired state. 9) is a Kubernetes resource used to manage stateful applications. StatefulSet también es un controlador, pero a diferencia del deployment, no crea ReplicaSet sino que crea el Pod directamente con una nomenclatura única. Kubernetes deployment strategies work by replacing pods of previous versions of your application with pods of the new version. 23 version is introducing some new and updated functionality, such as Pod Security Admission, Dual-stack IPv4/IPv6 Networking, Kubelet Container Runtime Interface, the general availability of Generic Inline Volume, and much more. Unlike a. A StatefulSet is a controller for stateful applications, such as databases, and manages the deployment and scaling of pods. “Kubernetes — Difference between Deployment and StatefulSet in K8s” is published by Ashish Patel. . This enables Kubernetes clusters. Unlike 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. PersistentVolumes and StatefulSets are the main approaches for running stateful applications in Kubernetes. Some of the key features of StatefulSets are as follows: 1. To decide how to handle updates, StatefulSets use an update strategy defined in spec: updateStrategy. StatefulSet workloads. 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. 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. 6+. There is around 250+ pods are running and HPA has been implemented on it too that can scale upto 400 pods. As a workload API object, a Kubernetes StatefulSet is used to manage stateful applications. StatefulSet Basics. It is resilient against node failures and ensures appropriate data archiving. You can define deployments to. StatefulSet. Although this is not directly answer your question, maybe it provides some hint for your consideration. If there's heavy load, you can set up a HorizontalPodAutoscaler to. A key feature with StatefulSet is that they provide unique stable network identities for the instances. 15. Let us see how StatefulSet differs from Deployment-1. The last section of the manifest defines our StatefulSet. This page describes the lifecycle of a Pod. 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". You should define a readiness probe, and the master will wait for it to report the pod as Ready. The hostnames are “${statefulset_name}-${index}“”. In robotics and automation, a control loop is a non-terminating loop that regulates the state of a system. StatefulSet Deployments provide: Stable, unique network identifiers: Each pod in a StatefulSet is. As far as I am aware, a StatefulSet will create node specific PVCs without a need for explicit PV and PVC set up, I see that PV being created but the pod status is 'pending' with below warning. By default, Kubernetes runs one instance for each Pod you create.