For this the recommended approach is to use a Deployment, which under the hood create a ReplicaSet. spec. The Deployment is managing the ReplicaSet and the ReplicaSet is managing the pods. 25, so it rounds up to 7. It manages the deployment and scaling of a set of Pods, and provides guarantee about the ordering and uniqueness of these Pods. . Deployment provides you the capabilities to upgrade your applications smoothly using rolling updates, undo changes, pause, and resume changes as required. Let’s dig deeper into Deployment Controllers and patterns. The situation is analogous to having a manager order "We need three workers doing this task at all times. k8s控制器--Replicaset和Deployment 一、Replicaset控制器 2. This means you can start with a Pod, and after a while you can add it to a Replicaset if you want to. Use kubectl to list information about the deployment. (No need for. Cet objet est souvent utilisé pour garantir la disponibilité d'un certain nombre identique de Pods. The ReplicaSet config file has two important features: Pod Template: A template for new Kubernetes pods. 27. Deployment supports the rolling update and. To deploy a replica set using an object, you must: Have or create an Ops Manager instance or a Cloud Manager organization. Create credentials for the Kubernetes Operator or configure a different secret storage tool. Imperative way: (this will then diverge from what you have in your yaml-file) kubectl scale deployment mage-di --replicas=2. You’ve completed the deployment of the MongoDB operator and ReplicaSets to your Kubernetes cluster at this point. A pod is the smallest unit of deployment in Kubernetes, consisting of one or more containers that share resources and networks. 2. This manifest will define the desired state of the ReplicaSet, including the pod template for your application. spec. Deployment adds flexibility to your Kubernetes cluster and eventually, to your application. Deployment is a supervisor for pods. @HunzlaSheikh When you run kubectl delete -f render. Deployment menurunkan kapasitas ReplicaSet yang lebih lama. When this ReplicaSet is created it will start the desired number of Pods from the template. The Scheduler, that is in charge of the pod resource allocation, commnd the kubelet, which reside on every worker nodes,. At the same time, Kubernetes Concepts page says about ReplicaSet object. 8 to deploy our software in a cloud provider. Click KUBERNETES OBJECT STATUS to see the object status updates. PodとReplicaSetが再作成されました。. The second line is when I triggered the update. The major components of a deployment are the deployment template, the persistent volumes and the service. The Desired field specifies the number of replicas you asked for, while the Current field specifies the number of replicas that are currently running in the system. When we create a Kubernetes Deployment with the name web-app, it will create a ReplicaSet with the name web-app-<replica-set-id>. Kubernetes - Deployment/replicaSet. Replicaset will only ensure that the replicas number of pods will be created on other nodes during the process. If you just have a Replicaset with one replica and no PodDisruptionBudget specified, the pod will be terminated and a new pod will be created on other nodes. As soon as new pods are started and ready. of pods are matching the specified no. 🕸️Simple Difference Between ReplicaSet and Deployment. Rolling Deployment. apps/myapp restarted. With ReplicaSet you define number of replicas you want to run. The kubectl set env command updates the environment variables for a Kubernetes resource, such as a Deployment, ReplicaSet, or StatefulSet. They let you perform rolling updates of ReplicaSets, where Pods are rescheduled. 롤링업데이트, 배포 중단, 롤백이 가능합니다. You may test it, after deleting the ReplicaSet and then typing the command kubectl get pods into the terminal. but the problem is i need to clean all old deployment and replica set once new version deployed successfully. The standard replica set deployment for a production system is a three-member replica set. Kubernetes deployments manage stateless services running on your cluster (as opposed to for example StatefulSets which manage stateful services). Let's take a brief look at the various options used with the command: webapp: The name of the Deployment--image=nginx: Specifies the name of the container image--replicas=2: Specifies the number of replicas (Pods) to run--dry-run=client: Used to preview the object instead of creating it--output=yaml: Specifies that the output format is. By default, it ensures that at most 125% of the desired number of Pods are up (25% max surge). A replica set, also known as a cluster, provides redundancy and availability. Puedes monitorizar el progreso de un Deployment usando el comando kubectl rollout status. It specifies the application's life cycle, including the pods assigned to the application. Version. g. Behind the scenes, Kubernetes stored numbers of old ReplicaSet so that you can switch to any Replicaset anytime. Important. A Deployment is another layer above ReplicaSets and Pods, newer and more advanced level concept than ReplicaSets. A ReplicaSet (RS) is a Kubernetes object used to maintain a stable set of replicated pods running within a cluster at any given time. 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. For now I'm able to increase the replicas from CLI using the command: kubectl scale --replicas=3 deployment my-deployment. The deployment controller extends the ReplicaSet Controller and is responsible for rolling out software updates when you create pods with deployment resources and update them with new versions of your software. ReplicaSet then fulfills its purpose by creating and deleting Pods as needed to reach the desired number. This is where you specify how the ReplicaSet should. 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. Replica sets provide redundancy and high availability and are the basis for all production deployments. In this case, you select a label that is defined in the Pod template (app: nginx). A ReplicaSet’s purpose is to run a specified number of pods at any given time. Rolling deployment is the default strategy in Kubernetes. kubectl -n eks-sample-app describe service eks-sample-linux-service. Offical Link. In the previous example, we scaled up the NGINX pods. how to refer ReplicaSet in deployment? 0. Normally, the old (previous). Deployment Patterns for MongoDB Replica Set. tier=backend. It uses the spec. Create a Service. spec. For example, If you create a deployment with 1 replica, it will check that the desired state of ReplicaSet. Process Name. ReplicaSet is the next-generation ReplicationController that supports the new set-based label selector. Here you see that when you first created the Deployment, it created a ReplicaSet (nginx-deployment-2035384211) and scaled it up to 3 replicas directly. StatefulSet is the workload API object used to manage stateful applications. When you update a Deployment, it will update the ReplicaSet, which in turn updates the Pods. OwnerReferences[0]. Three member Replica Set – the basic standard architecture for a replica set. Imperative way: (this will then diverge from what you have in your yaml-file) kubectl scale deployment mage-di --replicas=2. This way you could either, name the stateful-set according to the classes, i. From the table, you see one Kubernetes deployment. You will almost always use only Deployment for deploying an application, and for every change, e. This will likely be a ReplicaSet (which is generated by the Deployment). Deployment Strategy. ReplicaSet は Pod を作成して管理するが、 ReplicaSet が Pod を所有しているわけではない. This page shows how to run an application using a Kubernetes Deployment object. spec. In the case of a Job, this option is ignored. While ReplicaSets can be used independently, today it’s mainly used by Deployments as a mechanism to orchestrate. replicas: 2 a new ReplicaSet is created, and it observes the. Example: kubectl delete deployment hello-world -n mynamespace. However, ReplicaSet is still useful in certain cases where you only need the basic features of managing. configure ArgoCD / FluxCD / other deployment tool to delete them. The Deployment creates a ReplicaSet that creates three replicated Pods, indicated by the . vi d. caret right icon. name=backend. Next, create a release and a deployment for this project. The ReplicaSet uses a pod template with the app: web-app label, and the pod specification includes a container named web using the nginx image with specified resource limits and requests. If you check ReplicaSet after deploying a Deployment you will notice a ReplicaSet of the same name at the Deployment. The Deployment can manage multiple ReplicaSets in order to perfom rolling update of the. ConclusionThough the Deployment is more suitable than the ReplicaSet, this answer focuses on ReplicaSet over Pod cause the question is between the Pod and ReplicaSet. While ReplicaSets can be used independently, today they're mainly used by Deployments as a mechanism to orchestrate Pod creation, deletion and updates. ET. ReplicaSet is not suitable for applications that are going to have rolling updates and rollbacks. replicas field. 1. For the value. You would have those many replicas running. Alternatives to ReplicaSet Deployment (recommended) Deployment is an object which can own ReplicaSets and update them and their Pods via declarative, server-side rolling updates. every Kubernetes object has its own requirements. Ta thấy kết quả trả về có 1 ReplicaSet có tên là myapp-deployment-549fd4bf6c. Like a Deployment, a StatefulSet manages Pods that are based on an identical container spec. This annotation is set by Kubernetes. of pods are matching the specified no. While ReplicaSets can be used independently, today they're mainly used by Deployments as a mechanism to orchestrate Pod creation, deletion and updates. selector field defines how the created ReplicaSet finds which Pods to manage. When a Deployment is changed, a new ReplicaSet is created. It is a higher-level abstraction built on top of ReplicaSets that uses ReplicaSets internally to. The deployment process for Deployments is driven by a controller loop, in contrast to DeploymentConfigs which use deployer pods for every new rollout. Use this procedure to deploy a new replica set managed by Cloud. Now copy your deployment file to a master node and apply it. So the only way to do this is to scale down the number of replicas. How Deployment uses spec. yaml. Convert an existing standalone mongod instance into a three-member replica set. The deployment process for Deployments is driven by a controller loop, in contrast to DeploymentConfigs which use deployer pods for every new rollout. offer several benefits for managing application deployments:Good explanation what is event in Kubernetes you can find in Types of Kubernetes Events article. The deployment file contains details for a ReplicaSet that includes a PodTemplate. In this case, you select a label that is defined in the Pod template (app: nginx). If this isn't done, any time a change to that object is applied, for example via kubectl apply -f deployment. A ReplicaSet's purpose is to maintain a stable set of replica Pods running at any given time. When you revise a deployment, a ReplicaSet is. Và nhiệm vụ của ReplicaSet là luôn đảm bảo số lượng Pod (current) sẽ luôn là 10 (bằng với DESIRED). The straightforward way to achieve this is to create a service object that exposes the deployment. ロールアウトの再実行. The Kubernetes docs explicitly suggest using a deployment rather than a ReplicaSet directly. Declarative way, edit this line in your Yaml file: replicas: 2. kubectl get pods. A ReplicaSet is a process that runs multiple instances of a Pod and keeps the specified number of Pods constant. 2 Answers. spec. When you increase the replica count, to scale up your service. A replica set is a group of mongod instances that maintain the same data set. replicas field. Deployment is nothing but the higher-level of abstraction for Replicaset. Below is the yaml file for Deployment. I am not able to find a better description than kubectl describe deploy. For example, you define how many replicas ( pods) of your app you want to run in the. Provide a URL for accessing the API. Like a ReplicaSet’s purpose is to maintain a stable set of replica Pods running at any given time. Similar to a ReplicationController, a ReplicaSet is a native Kubernetes API object that ensures a specified number of pod replicas are running at any given time. ) Without RS, we will have to create multiple manifests for the number of pods we. This replica will further create a pod with name web-app-<replica-set->-<pod-id>. Deployment adalah sebuah objek yang bisa memiliki ReplicaSet dan memperbarui ReplicaSet dan Pod-nya melalui rolling update deklaratif dan server-side. Tested the field as below. This is where PDB s provide the added advantage over the Replicaset. Unlike a Deployment, a StatefulSet. . you can list all the pods in custom-namespace. Once your Pods have started, you can scale the StatefulSet up or down without risking the destruction of the MySQL primary node. Pod baru menjadi siap atau dapat diakses (siap selama setidaknya MinReadySeconds). 📍 Deployment vs ReplicaSet vs Pod: In Kubernetes, different objects serve various purposes when managing pods. In this case, you select a label that is defined in the Pod template (app: nginx). 決めた分だけ Pod の起動を維持してくれるし、これで事足りる。. spec. Replica Set is the next generation of Replication Controller. Note: You can use kubectl delete for both imperative commands and imperative object configuration. When a new version of an application is deployed, the Deployment creates a new ReplicaSet with. The random string is randomly generated and uses the pod-template-hash as a seed. El Deployment crea un nuevo ReplicaSet. Get the replicaset list for the Deployment we just created. Under the hood, Deployment creates a ReplicaSet which in turn creates pods on our cluster. Imperative config management with commands. The deployment process for Deployments is driven by a controller loop, in contrast to DeploymentConfigs which use deployer pods for every new rollout. Deployments. , but they are recreated again. yaml --record=true #get the replicaset list kubectl get rs #get the Pods list. Creating a ReplicaSet. Here the replicas field is set to 3, but you can set it to whatever fits your application. So, if you want to change anything in the pod Spec, you should make that change in the deployment, not in the replicaset or the pod directly as they will get overwritten. spec. also, another suggestion don't use the Replicasets by default Deployment create the Replicaset in the background. Its purpose is to maintain the specified number of Pod instances running in a cluster at any given time to prevent users from losing access to their application when a Pod fails or is inaccessible. yaml, this will instruct Kubernetes to scale the current number of Pods to the value of. To scale up set --replicas=1 (or any other required number) accordingly. Set any advanced configuration options for your MongoDB replica set. Kubernetes deployment drawbacks. Create a deployment configuration. Kuberneters – Difference Between Replicaset and Replication Controller. Walaupun ReplicaSet dapat digunakan secara independen, seringkali ReplicaSet digunakan oleh Deployments sebagai mekanisme untuk mengorkestrasi pembuatan, penghapusan dan pembaruan Pod. Number of seconds to sleep between checks. Additional replica sets in different Azure regions provide geographical disaster. This is needed for rolling upgrade, rollback functionsWhen you make any change in deployment, you’ll see there’s a new replicaset created. ( i. Create a secret that contains credentials for accessing a private image repository. For example, where we previously created a single instance of the Pod, we might create a Kubernetes Deployment YAML example to tell Kubernetes to manage a set of replicas of that Pod — literally, a ReplicaSet — to make sure that a certain number of them are always available. Declarative way, edit this line in your Yaml file: replicas: 2. Identifying specific replica in kubernetes deployment programmatically. 0. selector to know what Pods it should manage. In the simplest case, a deployment just creates a new replication. You can scale down to 3 by running the command below. Podの雛形 (Pod Template)を定義し、Label Selectorという方法で管理対象を. A DeploymentConfig (DC) in OpenShift is more or less equivalent to a Kubernetes Deployment, nowadays. Alternatives to ReplicaSet Deployment (recommended) Deployment is an object which can own ReplicaSets and update them and their Pods via declarative, server-side rolling updates. 由於 ReplicaSet 本身也會控制 Pod ，所以整個整體看起來就會像是 Deployment 控制著 Pod ，但其實Deployment 真正控制的是 ReplicaSet 喔！ Open the Create New Database Deployment dialog box. This will tell you what "owns" the pod. 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. 🔹 Pod: A pod is the smallest deployable unit in Kubernetes, representing a single instance of a running process. Cuando actualizaste el Deployment, creó un nuevo ReplicaSet (nginx-deployment-1564180365) y lo escaló a 1 y entonces escaló el viejo ReplicaSet a 2, de forma que al menos hubiera 2 Pods disponibles y como mucho 4 Pods en total en todo momento. Deployment Guidelines. Select the MongoDB version for your replica set. View the details of the deployed service. A Replicaset is a K8s object, a set of Pod templates that describe a set of Pod replicas. Deployment resources enable declarative updates of Pods and ReplicaSets. A ReplicaSet ensures that a specified number of pod replicas are running at any given time. Method 2: Configuring a MongoDB Replica Set for Deployment and Testing. yaml kubectl apply -f d. Most objects in Kubernetes have a metadata, it is responsible to store information about the resource like, name, labels, annotations and so on. Pod と ReplicaSet の関係は疎結合になっている。. reason: MinimumReplicasUnavailable message:. We have noticed in logs that pods, for old ReplicaSet (which still exists on the cluster), are regularly executed. The ReplicaSet config file has two important features: Pod Template: A template for new Kubernetes pods. Kubernetes has emerged as the de facto standard for container orchestration. Share. These sets provide redundancy and fault tolerance. Using a ReplicaSet: Non-Aware Application. As per the name, ReplicaSet is used for managing the replicas of our pods. A ReplicationController ensures that a specified number of pod replicas are running at any one time. Avoid complexity when possible, but let your application requirements dictate the architecture. Deployment sẽ sở hữu và quản lý các ReplicaSet của chúng. ownerReferences" field with the ID of that ReplicaSet. 0. It scales up 7 because 25% of 25 (your maxSurge value) is 6. selector field defines how the created ReplicaSet finds which Pods to manage. Implementation mechanism of garbage collection. Deployment object is a "abstract" layer for ReplicaSet creation and manage it. So, for example if we need our ReplicaSet to manage all pods with the label role=webserver, the controller will search for any pod with that label. Annotations are important for scraping pods for metrics. A Deployment allows you to create a newer revision of a ReplicaSet and then migrate existing pods from a previous ReplicaSet into the new revision. Whenever, you made some changes in deployment's podTemplate, it creates a new replicaset. kubectl create --help |awk '/Available Commands:/,/^$/' Available Commands: clusterrole Create a cluster role clusterrolebinding Create a cluster role binding for a particular cluster role configmap Create a config map. When any new update to the deployment is made the pods running are updated in rolling-update fashion meaning at first the K8s makes sure the new pods are able to. You can update image from v1 to v2. t. ReplicaSetCondition describes the state of a replica set at a certain point. In other words, a Deployment makes sure that a pod or homogeneous set of pods are always up and available. While ReplicaSets can be used independently, today they're mainly used by Deployments as a mechanism to orchestrate Pod creation, deletion and updates. As an alternative to using this procedure, you can use. While this command doesn’t explicitly restart any Pods, it. A. Under the hood, Deployment creates a ReplicaSet which in turn creates pods on our cluster. yaml This starts rolling out a new replicaset R_new. 下記の図のようにDeploymentはReplicaSetを生成・管理し、ReplicaSetはPodを生成・管理します。 This way the deployment will be marked as paused and won't be reconciled by the controller. How does a deployment work? Behind the curtains, when you create a new deployment, K8s creates two different objects: a Pod definition, using as its specification what is available in the “template” field of the Deployment, and a ReplicaSet. Avoid complexity when possible, but let your application requirements dictate the architecture. The . The old ReplicaSet is scaled down as the new one is scaled up, ensuring that the. 9k 45 151 238 asked Mar 25, 2016 at 12:56 David Knell 997 1 9 10 1 I am having the same question at the moment. metadata: annotations: deployment. Add a new member to an existing replica set. You can define a deployment to create a ReplicaSet or to remove deployments and adopt all their resources with new deployments. kubectl apply -f dp. Have or install the MongoDB Enterprise Kubernetes Operator. Unlike a. In addition, each one of the above controllers has it's own purpose. Alternatives to ReplicaSet Deployment (recommended) Deployment is an object which can own ReplicaSets and update them and their Pods via declarative, server-side rolling updates. Although ReplicaSet 's main purpose is to maintain a stable set of replica Pods, it's not a kubernetes object that is commonly created, at least not explicitly. yaml. I'm trying to delete some old deployments / replicasets I have in my cluster but when I run kubectl delete deployment It'll say the deployment is deleted and the pod from that deployment is Terminating, but then a few seconds later the deployment is magically recreated and the pod comes back. When to use a ReplicaSet. Whenever we create a new deployment, K8s triggers a Rollout. The United States and China, the world’s two largest climate polluters, have agreed to jointly tackle. However, Deployment is a higher-level concept that manages ReplicaSets and provides declarative updates to Pods along with a lot of other useful features. mongosh --port 28015. Improve this answer. What is a ReplicaSet?. # deployment name and namespace deployment_name=mydeployment deployment_ns=mynamespace # get replica set identifier for deployment dep_rs=$ (kubectl describe. Reload to refresh your session. schedulerName field of the DaemonSet. The running instances are located in multiple locations. Whereas Deployment is the advancement of replica sets. When to use a ReplicaSet. It also needs to check whether the target pod is already managed by another controller (like a Deployment or another ReplicaSet). The Deployment is scaling up its newest ReplicaSet. replicas of the Deployment and / or StatefulSet be removed from their manifest (s). A ReplicaSet (RS) is a Kubernetes object that ensures there is always a stable set of running pods for a specific workload. " In order to keep. io/revision annotation. template. A ReplicaSet is a Kubernetes object that ensures that a specified number of replicas of a pod are running at any given time. When you create a ReplicaSet, you are essentially telling Kubernetes that you want a specific pod replicated x amount of times. Add a comment. By default, every Deployment is set to 10 for reserving the old. The nodeapp-deployment is the deployment name which is already. yaml replicaset "soaktestrs" created Check the Status of a ReplicaSet Once the ReplicaSet is created, we can use the describe command to check the status of the pods and get more detail. これまで、Pod、ReplicaSetの動作を確認してきましたので、今回はDeploymentの動作を確認します。 Deploymentは、ReplicaSet、Podの上位概念で、以下のような関係になります。 Deploymentの作成 yamlファイルの作成とapply. Let's use the official example of a Deployment that creates a ReplicaSet to bring up three nginx Pods:If you deploy a pod from deployment object, kind:Deployment, then the deployment controller appends a unique name to pod that is part of specific deployment. 2. If there are too many pods, it will kill some. You switched. The Replica Set Controller detect the change then according to the number of replica, create Pod objects. Deployment status, notice only 2 ready replicas:A new deployment has been created and the release was successfully deployed on our AKS cluster. Manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods. Deployment creates ReplicaSet with the number of replicas=3. El Deployment está reduciendo su(s) ReplicaSet(s) más antiguo(s). To work with Namespace, you need to add --namespace flag to k8s commands. nodeAffinity field (if specified) is taken into consideration by the DaemonSet controller when evaluating the eligible nodes, but is. リソース 役割; Deployment: ReplicaSetを生成、管理しローリングアップデートやロールバックといったデプロイ管理を行います。: ReplicaSet: 同じ仕様のPodのレプリカ数を管理します。ReplicationControllerの後継に当たるものです。: Pod: アプリケーションを動かすための最小単位。To make changes in your current deployment you can use kubectl rollout pause deployment/YOUR_DEPLOYMENT. 9) is a Kubernetes resource used to manage stateful applications. A Deployment is a higher-level resource meant for deploying applications and updating them declaratively, instead of doing it through a ReplicationController or a ReplicaSet, which are both considered lower. In mongosh, use rs. But the replicas attribute on the Deployment object is actually related to this object. It increases the pods one by one while the old replicaset decreases the pods one by one. ¶ The Advanced Configuration Options section allows you to set MongoDB runtime options for each MongoDB process in your deployment. By default, Kubernetes keep 10 replica sets for each deployment, which means you can go back 9 versions prior. New Pods become ready or available (ready for at least MinReadySeconds). Deployment is an advanced replication set that will manage the lifecycle of pods. To create a ClusterIP service (default), use the following command: $ kubectl expose deployment nginx-deployment –name my-nginx-service –port 8080 –target-port=80. The kubectl create deployment command causes Kubernetes to create a Deployment named monolith on. 1. This is how the deployment controller looks up all the relevant pods of respective deployment. ownerReferences pointing to your Deployment (owner) and by design they should be removed first from Kubernetes 1. The Deployment helps move between different versions of applications in the above diagram by moving between different Replicaset versions. . spec. It is a Kubernetes controller that matches the current state of your cluster to the desired state mentioned in the Deployment manifest. The --port command-line option. Completar un. Actually, you will notice that the only change between declaring a Deployment and a ReplicaSet is the kind Note: A Deployment that configures a ReplicaSet is now the recommended way to set up replication. 8 user guide shows how to create a deployment in. A standalone instance isn't a good choice for a production deployment because it can be a single point of failure. StatefulSet lets you run one or more related Pods that do track state. El Deployment está escalando su ReplicaSet más nuevo. Kubernetes marks a Deployment as complete when it has the following characteristics:Relationship between Deployment and ReplicaSet in kubernetes. Replica Count: The number of replicas (pods) the controller should. Now that we have learned about ReplicaSet and Deployment, let’s summarize their key differences: Abstraction level: A Deployment is a higher-level abstraction that. Once your Pods have started, you can scale the StatefulSet up or down without risking the destruction of the MySQL primary node. A ReplicaSet ensures that a specified number of Pod replicas are running continuously and helps with load-balancing in case of an increase in resource usage. 0. Like deployment replicaset cant rollout or rollback to different version of application nor maintain any revisions for the same. The rules are of the form "this pod should (or, in. In kubernetes where pods are controlled by the replicaSet, if you kill a pod it will again be recreated. However, a Deployment is a higher-level concept that manages ReplicaSets and provides declarative updates to pods along with a lot of other useful features. I am not going to explain this approach in details because the link I provided is quite. ReplicaSet and PODS are associated with the selectors. yml deployment. 4. The .