The last section of the manifest defines our StatefulSet. kubectl create namespace database. The manifest files do not have the namespace added to them. g. In a typical Kubernetes cluster, there are several components that run on each node, as well as. This article describes how to create, update, and delete StatefulSets, which are used to maintain the state of an application beyond a pod lifecycle in an Azure Kubernetes Serice deployment in AKS hybrid. persistent buffering to disk), use a StatefulSet. Like a Deployment, a StatefulSet manages Pods that are based on an identical container. However, while Elasticsearch uses terms like cluster and node, which are also used in Kubernetes, their meaning is slightly different. A Pod (as in a pod of whales or pea pod) is a group of one or more containers, with shared storage and network resources, and a specification for how to run the containers. 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. Now, I have a task to. If. It ensures that the desired number of replicas (PODs with the application running), as mentioned while creating the Replicaset, is always maintained. Description. g. Check. In contrast, annotations are not used to identify and select objects. pod. Share. StatefulSets. A ReplicaSet (RS) is a Kubernetes object used to maintain a stable set of replicated pods running within a cluster at any given time. ReplicaSet vs. StatefulSet ensures that, at any time, there is at most one Pod with a given identity running in a cluster. StatefulSet. Rather, a deployment is a file that defines a pod's desired behavior or characteristics. Each Pod has init and main container. spec. This is important because many stateful applications have data initialization routines to perform, masters to elect, and quorum to achieve. In this video I show the syntax and contents of the configuration file by showing how to create and connect deployment and service component. kubectl create namespace database. Each cluster contains one or more nodes. Above is one example of a Deployment Strategy called Blue/Green. Deployment vs StatefulSet. A StatefulSet is a controller that helps you deploy and scale groups of Kubernetes pods. However, the order matters in a StatefulSet, and K8s will maintain that order when scaling up or down to ensure stability. How to run stateful applications in Kubernetes. 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). This tutorial provides an introduction to managing applications with StatefulSets. But even when i got reclaimPolicy:. php with a username/password that it. In Kubernetes, a HorizontalPodAutoscaler automatically updates a workload resource (such as a Deployment or StatefulSet), with the aim of automatically scaling the workload to match demand. StatefulSet (stable-GA in k8s v1. As a workload API object, a Kubernetes StatefulSet is used to manage stateful applications. kubectl create -f ssd-storageclass. All of the other parts are ready and we will just plug in the engine and we will be ready to hit the road. 只能用StatefulSet: 最近在微软的aks平台上部署服务，由于Deployment在scale的时候需要动态申请volume，采取使用volumeClaimTemplates属性的方式来申请，当前Deployment对象（1. Ingress frequently uses annotations to configure some options depending on. See StatefulSet vs. Kubernetes deployment persistent volumes are used to create a layer of abstraction between pods and their provisioned storage, allowing each to be managed separately. k8s. The application is MySQL. Meaning you can create a Replica set containing only one Pod specifying to run only one instance of that Pod. for all of your k8s troubleshooting needs, Komodor offers: Change. Create a file called redis-sts. Authors: Mahamed Ali (Rackspace Technology) The Kubernetes project runs a community-owned image registry called registry. StatefulSet(stable-GA in k8s v1. There are many benefits. Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. Like a Deployment, a StatefulSet manages Pods based on an identical container specification. replicas is not equal to status. io. 1 Answer. 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. Overview of the content: 3 parts of a Kubernetes configuration file. Kubernetes provides a basic resource called Pod. Minikube is a tool used to run a single-node Kubernetes cluster locally. Minikube. A pod is the smallest deployable unit in Kubernetes which has a collection of containers. Apache Spark is a stateful service, those should be deployed as StatefulSet. Finally, we will visualize and monitor all our data in. When it comes to Kubernetes, you can scale: 1. Attributes of a Highly Available WordPress Deployment. If you want to provide workload persistence using Kubernetes persistent storage, you can incorporate a StatefulSet into your. 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. Autoscaling is a process that dynamically scales up or down any components of your architecture. apps. 9. Additionally, StatefulSet maintains a sticky. First, the (1) pod comes up, initialized, and then settles into a “ready” state. Helm Cons. Deploying a Stateful Application Using Kubernetes Statefulset. Many different settings impact Kubernetes API security, requiring significant knowledge to implement correctly. Both Deployment and StatefulSet try to maximize the availability - but StatefulSet cannot sacrifice data consistency (e. g. It is rather unlikely that you will ever need to create Pods directly for a production use-case. Learn how to run stateful applications on Kubernetes, understand how pods work in a StatefulSet, and see how to create a StatefulSet. MySQL settings remain on insecure defaults to keep the focus on general patterns for running stateful. WordPress is a stateful application the relies on two persistence backends: A file system and MySQL database. It's designed to get a cluster up and running quickly so you can start interacting with the Kubernetes API locally. A StatefulSet is a workload object that makes it possible to deploy Pods (which host Kubernetes workloads) with unique identifiers – which you don't get from a standard Kubernetes deployment. yaml. Then we run the command for the deployment template : kubectl apply -f demo-deployment. g. Note: This is not a production configuration. This causes the Pods of your Deployment to be restarted, in which case they read the updated ConfigMap. 2. You might set the Deployment to have replicas: 3 so that if one of them fails the other two can pick up the load. They use a K8S component called Service, to group the pods using labels. Kubernetes StatefulSet is the workload API object used to manage stateful applications. Waypoint helps simplify the deployment process with its Helm plugin and does so automatically with its Git integration and GitOps. If this is a serious project you should definitely change it to a statefulset. Unlike a Deployment, a StatefulSet has a persistent ID for each Pod that persists across any rescheduling or. It was initially developed by Google for the purpose of managing containerized applications or microservices across a distributed cluster of nodes. A StatefulSet is a set of pods with a unique, persistent hostname and ID. 3. cluster. Manages the deployment and scaling of a set of Pods, and provides. service. moury~ % kubectl scale statefulset web --replicas=3 statefulset. This page shows you how to run a single-instance stateful application in Kubernetes using a PersistentVolume and a Deployment. Manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods. First, the (1) pod comes up, initialized, and then settles into a “ready” state. Read more: Kubernetes StatefulSet: A Practical Guide. StatefulSet. A deployment is responsible for keeping a set of pods running. 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. Each Pod in the StatefulSet gets a name generated by suffixing the pod ordinal to the StatefulSet name. Trident automatically caters to persistent volume claims in Kubernetes by leveraging Azure disk storage, AWS EBS block storage, GCP Persistent Disks via Cloud Volumes ONTAP or on-premises ONTAP appliances. Un StatefulSet es el objeto de la API workload que se usa para gestionar aplicaciones con estado. Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. 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. Deployment vs StatefulSet. 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. Version the ConfigMap. Deployment vs StatefulSet component Pods deployed by Deployment are identical and interchangeable, created in random order with random hashes in their Pod. 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. Understanding init. Horizontal scaling means that the response to increased load is to deploy more Pods. Then we run the command for the deployment template : kubectl apply -f demo-deployment. These pods are created from the same spec, but are not interchangeable: each has a persistent identifier that it maintains across any rescheduling. 2 Answers. Let us see how StatefulSet differs from Deployment-1. When the pod fails and stops logging, the kubectl logs -f mypod will terminate and then the shell will immediately execute kubectl describe pod mypod, (hopefully) letting you catch the state of the failing pod before it is recreated. Deployment; ReplicationController; ReplicaSet; StatefulSet; In this case, make a note of the controller's . In robotics and automation, a control loop is a non-terminating loop that regulates the state of a system. Example code for HPA:Apr 6, 2020 at 8:53. A Kubernetes pod is a cluster deployment unit that typically contains one or more containers. These priorities does not only happens when a Node becomes unreachable, but at all times, e. In short, a pod is the core building block for running applications in a Kubernetes cluster; a deployment is a management tool used to control the way pods behave. This is useful when the database itself knows how to replicate data between different copies of itself. Resource objects typically have 3 components: Resource ObjectMeta: This is metadata about the resource, such as its name, type, api version, annotations, and labels. Pods created as part of a StatefulSet are given persistent identifiers that they retain even when they’re rescheduled. You can use statefulsets if you want fixed pod names for your application. “Kubernetes — Difference between Deployment and StatefulSet in K8s” is published by Ashish Patel. 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. This blog post will discuss how this feature can be used. api. Unlike a Deployment, a StatefulSet maintains a sticky, persistent identity for each of their Pods. At the highest level, a. Introduction to autoscaling in k8s. 10 how you can do it, where. StatefulSets. 9) is a Kubernetes resource used to manage stateful applications. 27, this feature is now beta. 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). If we need to update the application to a new version, we can change the fields in the Deployment YAML file. I'm using Logstash on Kubernetes and use the official Helm chart at this link. The setup is also scalable. v1. NetApp Trident is a dynamic container storage interface (CSI) for use in Kubernetes. Deploying a MongoDB Database: Here is an example of how to deploy a MongoDB database using a StatefulSet in Kubernetes. Deploying workloads as StatefulSet helps provide features like unique. kubectl rollout undo deployment/<deployment name> – Rollback a. Applications that are stateless follow the Twelve Factor App principles. As developers, we learned a lot building these Operators. See full list on baeldung. your state), so it cannot act as fast as Deployment (stateless) apps can. Por ejemplo, si creamos un StatefulSet. It makes sense also as each Redis instance relies on a configuration file that keeps track of other cluster instances and their roles. I'll try removing some parts of the alertmanager deployment to identify the issue. They both make it easy to orchestrate multiple. This application is a replicated MySQL database. This controller runs Jobs -- components of a Kubernetes workload that execute specific tasks -- according to. Deployment. This page shows how to run a replicated stateful application using a StatefulSet. apiVersion. g. RollingUpdate: The RollingUpdate update strategy implements automated, rolling update for the Pods in a StatefulSet. network issue), for Deployment, a new Pod will be created on a different node (to follow your desired 1 replica), but for StatefulSet it will make sure to terminate the existing Pod before creating a new, so that there are never more than 1 (when you have 1 as desired number of replicas). The termination of Pods is performed in reverse {N-1. StatefulSets. 1. In this article, we’ll take a look at the differences between Deployment and StatefulSet and when you should use one over the other. Deployment modes A bare metal deployment of the collector is simple to plan and execute: it’s a single binary that runs as a daemon on the host. apps. Introduction A StorageClass provides a way for administrators to describe the "classes" of storage they offer. It manages the deployment and scaling of a set of Pods, and provides guarantee about. Community. To deploy the PostgreSQL cluster, we will create a dedicated namespace named database. conditions[1): unknown field "lastUpdateTime" in io. But it differs from a Deployment in that it is more suited for stateful apps. The number of required nodes of our cluster. It allows storage providers to deploy plugins through standard k8s primitives like storage classes, PersistentVolumes (PVs) and PersistentVolumeClaims (PVCs). e. StatefulSet and deployment controllers. if the node becomes unreachable (e. They keep unique identities for each Pod they manage and use the same identity when Pods need to be rescheduled. Because the replicas field of the nacos StatefulSet is set to 2, In the cluster file only two nacos address. Replicas in a StatefulSet follow a graceful, sequential approach to deployment, scale, upgrade, and termination. Deploy and Manages the stateless application. They let you ensure that pods are scheduled in a specific order, that they have persistent storage volumes available, and that they have a persistent network ID that is maintained even when a pod shuts down or is rescheduled. StatefulSet lets you run one or moreThe ‘kubectl rollout’ command is used to manage the rollout process for three Kubernetes objects: Deployment, DaemonSet, and StatefulSet. kubectl describe svc nginx-app1. 15）不支持这一属性，只有StatefulSet才有，因此不得不使用后者。. The example topology has a single primary server and multiple replicas, using asynchronous row-based replication. Resource Objects. yaml. g. Al igual que un Deployment, un StatefulSet gestiona Pods que se. Nota: Los StatefulSets son estables (GA) en la versión 1. Each Pod in a StatefulSet derives its hostname from the name of the StatefulSet and the ordinal of the Pod. field to . This name will become the basis for the ReplicaSets and Pods which are created later. First, we will create a persistent volume claim for the storage we need. Author: Deepak Kinni (VMware) PersistentVolume (or PVs for short) are associated with Reclaim Policy. 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. Nó sẽ được tạo tuần tự. 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. Pods use a persistent volume claim as a request for storage that is matched to a persistent volume by the Kubernetes cluster. For example, you define how many replicas ( pods) of your app you want to run in the. k8s. In the YAML manifest file the replicas was set to 3. En esta entrada vamos a tratar sobre aplicaciones Stateful en Kubernetes – Statefulset, el cual es un tipo de recurso que nos ofrece Kubernetes. Using volumeClaimTemplates, each replica will get a unique PersistentVolumeClaim with statefulset whereas all replicas would share the PersistentVolumeClaim with a deployment. ** Notes. If you don’t have a Deployment or StatefulSet managing your pods, you can delete the existing pods and let Kubernetes recreate them with the same configuration. yaml with the following: What will happen here is that on 6 nodes of the cluster we will run a Redis. Kubernetes administrators define classes of storage, and then pods can dynamically request the specific type of storage they need. 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. It allows you to define the Kubernetes Deployment or StatefulSet that you want KEDA to scale based on a scale trigger. Just like StatefulSets, Kubernetes Deployments let you define the state of the application, and the Deployment’s controller is responsible for maintaining this state. StatefulSet. Manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods. The . Kubernetes (K8s) is one of the popular open-source container orchestration systems for automating deployment, scaling, and management of containerized applications. In a stateful containerized application, data must be persistent, retained and easy to access outside the application. In this guide, we explain to readers the differences between using a Kubernetes statefulset, versus using a deployment, as well as the use cases for each. 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). DaemonSets. Use multiple nodes. Question. Get Full-Length High-Quality DevOps Tutorials for Free - Subscribe Now. 7 Answers. It is the default strategy when . When first deploying the OpenTelemetry Collector, you can start with a single replica deployment within a Kubernetes cluster, or for additional scalability, deploy Collectors as a DaemonSet to scrape appliction metrics. What happens when we upgrade a Statefulset to a. 目前看来有点本末倒置，不过不. E. You need to mount the configMap rather than use it as an environment variable, as the setting is not a key-value format. Kubernetes offers a highly resilient infrastructure designed for zero downtime deployment, with capabilities such as scaling. Kubernetes users don’t need to worry about how pods are scheduled—they can deploy pods sequentially, attach them to persistent storage volumes, and each pod maintains its own persistent network ID. 1. 9. Simply use a volume in the required Resources and K8S will take care of that for you. 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. Get Full-Length High-Quality DevOps Tutorials for Free - Subscribe Now. zk-0 zk-1 zk-26. We’re rapidly growing and always welcome new contributors. Pods. When a StatefulSet's . k8s. This document describes the concept of a StorageClass in Kubernetes. To scale Kubernetes Deployments only name is needed to be specified, if one wants to scale a different resource such as StatefulSet or Custom Resource (that defines /scale. 1. Deleting and/or scaling a StatefulSet down will not delete the volumes associated with the. DaemonSet vs. If your application is stateless, you should use Deployment and not StatefulSet. The Replica set can contain one or more pods and each pod can have one or more instances. Because the replicas field of the zk StatefulSet is set to 3, the Set's controller creates three Pods with their hostnames set to zk-0, zk-1, and zk-2. io will be frozen and no further images for Kubernetes and related subprojects will be pushed to the old registry. Once you’ve defined and. Kubernetes provides a basic resource called Pod. There are also some deprecations like the deprecation of klog specific flags. 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. Deployment: Pods have an ID that contains the. In contrast to that, the Pods deployed by StatefulSet component are NOT identical and deployment is more complex. 10 sidecar injection. Editor’s note: this post is part of a series of in-depth articles on what's new in Kubernetes 1. While StatefulSet is used for stateful applications like databases, Deployment component is used to deploy stateless applications. Gestiona el despliegue y escalado de un conjunto de Pods, y garantiza el orden y unicidad de dichos 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. Updates are versioned and you can revert to any previously known state of a Deployment. yml3. It will trigger them all at once. Quick tutorial #1: Mounting an NFS share on a container. status. Deploy Istio and validate its installation. The metadata in an annotation can be small or large, structured or unstructured, and can. As the name suggest the statefulsets are specifically used to make sure the app state is saved by each running pod. 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. Kubernetes headless service is a Kubernetes service that does not assign an IP address to itself. StatefulSet(stable-GA in k8s v1. availableReplicas . 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 following provides an example of deploying a single Kubernetes MySQL instance using Trident. Related Resources. Deploying a Stateful Application Using Kubernetes Statefulset. The StatefulSet name is derived from the Elasticsearch resource name and the NodeSet name. You should then probably use StatefulSet and volumeClaimTemplates within it instead of Deployment and PersistentVolumeClaim. a cache or database cluster even though it may solve your specific situation as. So, to create a dummy deployment we use: bash. StatefulSet is a Kubernetes controller used to deploy stateful apps. v1. We are going to take a deeper dive into Blue/Green as well as two more deployment strategies: Canary and A/B Testing. This cheatsheet will serve as a quick reference to make commands on many common Kubernetes components and. spec): missing required field "serviceName" in io. This is great for stateless apps that we want online, ASAP. First, we run the service template : kubectl apply -f service. If a Pod cannot be scheduled, the scheduler tries to preempt (evict) lower priority Pods to make scheduling of the pending Pod possible. Rolling Update Strategy. Encode Decode. Pods (and, by extension, containers) are, nevertheless, short-lived entities. Create namespace, storageclass, Google compute Disk and persistentvolumes. kubectl basics. yaml storageclass. First, do a git pull to ensure you’re working on the latest revision: $ git pull origin setup-semaphore. By baking K8s. Full k8s cluster consists of 4–5 services on the control plane and two on worker nodes. 3. 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. Read more about StatefulSet here. 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 que veas las diferencias entre Stateful y Stateless en una. The naming convention, network names, and storage persist as replicas are rescheduled with a StatefulSet. Step 1. e. Apr 6, 2020 at 8:53. kubectl delete pods -l app=wiki. This is different from vertical scaling, which for Kubernetes would. Let’s now create the Deployment using the kubectl apply command: $ kubectl apply -f deployment. Kubernetes or K8s is an open-source orchestration system for containerized applications that helps in automating software deployment, management and scaling. ValidationError(StatefulSet. if the node becomes unreachable (e. Define a Stateful Set with PVC. A stateful application requires pods with a unique identity (for example, hostname). The hostnames take the form of <statefulset name>-<ordinal index>. K8s doesn't add any "magic" to make it easier, it only offers. podManagementPolicy. I'm not sure if this is what you are looking for but you can scale a StatefulSet. A Replicaset is a K8s object, a set of Pod templates that describe a set of Pod replicas. spec. e. 1. For general information about working with config files, see deploying applications, configuring containers, managing resources. I am curious to know how to do deployment when we have a service dependency!. Follow the official Get Started guide to get Minikube installed along with:. you can do that by entering the following command: touch example-statefulset. Using volumeClaimTemplates, each replica will get a unique PersistentVolumeClaim with statefulset whereas all replicas would share the PersistentVolumeClaim with a deployment. The most basic difference is that you would get ability to persist pod level state with statefulsets. We assign it a service name, specify a single replica,. Deploying a. 10. Deploying the Headless Service and. The StatefulSet controller provides each Pod with a unique hostname based on its ordinal index. StatefulSetCondition describes the state of a statefulset at a certain point. Scaling a StatefulSet refers to increasing or decreasing the number of replicas. You can add these custom entries with the HostAliases field in PodSpec. The new pod will automatically spin up with correct configuration. vim redis-statefulset. Create a StatefulSet file. Behind the scenes, the Deployment object creates ReplicaSets to run the required instances. 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. you need to create a StatefulSet configuration file that deploys the desired number of. Example-2: Define runAsUser for container. Define the application in YAML format using kind: StatefulSet. The Elasticsearch Operator I’ll be using in this tutorial is the official Operator from Elastic. To check your version of Kubernetes, run kubectl version. I've installed these components in the k8s cluster using the mixin kube-prometheus. It is mainly designed to use for stateful apps. First, let's verify that StatefulSet has created the leader ( mehdb-0) and. The main benefits of these Kubernetes deployment strategies are that it. Both Pod and Deployment are full-fledged objects in the Kubernetes API. 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). k8s. It makes sense also as each Redis instance relies on a configuration file that keeps track of other cluster instances and their roles. StatefulSet - manages/maintains stable hostname, network ID and persistent storage. 5 In the latest release, Kubernetes 1. This service will need to be created with: selector: statefulset. Deployment is a good fit for managing a stateless application workload on your cluster, where any Pod in the Deployment is interchangeable and can be replaced if needed. Retain and then reference that in my deployment. It automates the deployment, provisioning, management, and orchestration of Elasticsearch on Kubernetes. Your Deployment yaml should be like below: containers: - name: nginx image: nginx volumeMounts: - mountPath: /etc/nginx name: nginx-conf volumes: - name: nginx-conf configMap: name: nginx-conf items: - key:. Horizontal scaling means that the response to increased load is to deploy more Pods. First, find the StatefulSet you want to scale. Here is a step by step tutorial on how to use StatefulSets and some basic operations on StatefulSets. StatefulSet también es un controlador, pero a diferencia del deployment, no crea ReplicaSet sino que crea el Pod directamente con una nomenclatura única. 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. Deployment and StatefulSet are two of the most popular and powerful features of Kubernetes. Unlike a. yaml file, you will find a snippet around how we are deploying a stateful application. But it differs from a Deployment in that it is more suited for stateful apps. g. 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. StatefulSet is a workload API object designed to assist in managing stateful applications. On an update the existing Pods will get deleted and recreated. For example, to create and check a service configuration for an Nginx application, use the following: kubectl expose deployment/nginx-app1. It can manage the scaling and deployment of a collection of.