Pods in a StatefulSet have a unique ordinal index and a stable network identity. From this, we can extract the ordinal index from each pod from the network ID, and use an initContainer to selectively load the respective configuration … All Pods with an ordinal that is less than the partition will not See also. StatefulSet controller will delete and recreate each Pod in the StatefulSet. Before you begin Before you begin this tutorial, you should familiarize yourself with the following Kubernetes concepts: Pods Cluster DNS Headless Services PersistentVolumes PersistentVolume Provisioning StatefulSets … Negative caching (normal in DNS) means that the results of previous failed lookups are Index core About core Binding [core/v1] ... Partition indicates the ordinal at which the StatefulSet should be partitioned. StatefulSets do not provide any guarantees on the termination of pods when a StatefulSet is deleted. When Kubernetes decides to scale up or scale down a StatefulSet, it does it in a well-understood way. In my use case, I need to access to POD Index from Spring Boot application.yaml, which meant there was only one solution - Get the value from Environment Variable. 3. $ kubectl get statefulsets.appskNAME READY AGEweb 2/2 2m27s $ kubectl get podsNAME READY STATUS RESTARTS AGEweb-0 1/1 Running 0 2m31sweb-1 1/1 Running 0 105s $ kubectl get persistentvolumesNAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGEpvc-19ef374f-39d1-11e9-b870-9efb418608da 1Gi RWO Delete … (If yes, you should use our troubleshooting guide and community support channels, see http://kubernetes.io/docs/troubleshooting/. By clicking “Sign up for GitHub”, you agree to our terms of service and Ready (for example, due to a bad binary or application-level configuration error), StatefulSet will then begin to recreate the Pods using the reverted template. You are using an template generator (helm? It's absurd that this hasn't been addressed, there was a feature request for this back when it was called petset. StatefulSet Pods have a unique identity that is comprised of an ordinal, a In the nginx example above, each Pod will receive a single PersistentVolume would you tell me how can I append the ordinal index into the volumeClaimTemplates.spec.selector.matchLabels? StatefulSetStatus represents the current state of a StatefulSet. /lifecycle stale. ), there u should have the ordinal variable report a problem as an env var. name for a newly-run Pod immediately. StatefulSet name, and how that affects the DNS names for the StatefulSet's Pods. The RollingUpdate update strategy can be partitioned, by specifying a This identity is based on a unique ordinal index that is assigned to each Pod by the Stateful Set controller. This manifest includes several configs that we haven’t talked about including initcontainers. It looks there is no update yet, I've made a workaround by developing custom k8s admission controller - sts-annotator. responsible for the network identity of the pods. Ordinal Index. StatefulSets in Kubernetes are used for applications where data consistency and replication is required (relational databases). to your account, Is this a request for help? and disable automated rolling updates for containers, labels, resource request/limits, and Send feedback to sig-testing, kubernetes/test-infra and/or fejta. At least three nodes in each data center where Kubernetes can deploy pods Figure 1 shows the setup with five nodes in each data center. it adds a label, statefulset.kubernetes.io/pod-name, that is set to the name of Default value is 0..status. It looks like the proposal was accepted, but was it actually implemented? The Pod identity starts from 0 to N-1 ordinal set. replicas. Ordered operations with ordinal index. As I wanted to have POD Replicas in env var as well and also wanted a consistent solution for all applications, I developed the custom controller though, your solution is also great. Here, Kubernetes is using them to order, as well as identify each Pod. Manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods. Last modified November 02, 2020 at 10:30 PM PST: # has to match .spec.template.metadata.labels, # has to match .spec.selector.matchLabels, Kubernetes version and version skew support policy, Installing Kubernetes with deployment tools, Customizing control plane configuration with kubeadm, Creating Highly Available clusters with kubeadm, Set up a High Availability etcd cluster with kubeadm, Configuring each kubelet in your cluster using kubeadm, Configuring your kubernetes cluster to self-host the control plane, Guide for scheduling Windows containers in Kubernetes, Adding entries to Pod /etc/hosts with HostAliases, Organizing Cluster Access Using kubeconfig Files, Resource Bin Packing for Extended Resources, Extending the Kubernetes API with the aggregation layer, Compute, Storage, and Networking Extensions, Check whether Dockershim deprecation affects you, Migrating telemetry and security agents from dockershim, Configure Default Memory Requests and Limits for a Namespace, Configure Default CPU Requests and Limits for a Namespace, Configure Minimum and Maximum Memory Constraints for a Namespace, Configure Minimum and Maximum CPU Constraints for a Namespace, Configure Memory and CPU Quotas for a Namespace, Change the Reclaim Policy of a PersistentVolume, Control CPU Management Policies on the Node, Control Topology Management Policies on a node, Guaranteed Scheduling For Critical Add-On Pods, Reconfigure a Node's Kubelet in a Live Cluster, Reserve Compute Resources for System Daemons, Set up High-Availability Kubernetes Masters, Using NodeLocal DNSCache in Kubernetes clusters, Assign Memory Resources to Containers and Pods, Assign CPU Resources to Containers and Pods, Configure GMSA for Windows Pods and containers, Configure RunAsUserName for Windows pods and containers, Configure a Pod to Use a Volume for Storage, Configure a Pod to Use a PersistentVolume for Storage, Configure a Pod to Use a Projected Volume for Storage, Configure a Security Context for a Pod or Container, Configure Liveness, Readiness and Startup Probes, Attach Handlers to Container Lifecycle Events, Share Process Namespace between Containers in a Pod, Translate a Docker Compose File to Kubernetes Resources, Declarative Management of Kubernetes Objects Using Configuration Files, Declarative Management of Kubernetes Objects Using Kustomize, Managing Kubernetes Objects Using Imperative Commands, Imperative Management of Kubernetes Objects Using Configuration Files, Update API Objects in Place Using kubectl patch, Define a Command and Arguments for a Container, Define Environment Variables for a Container, Expose Pod Information to Containers Through Environment Variables, Expose Pod Information to Containers Through Files, Distribute Credentials Securely Using Secrets, Run a Stateless Application Using a Deployment, Run a Single-Instance Stateful Application, Specifying a Disruption Budget for your Application, Coarse Parallel Processing Using a Work Queue, Fine Parallel Processing Using a Work Queue, Use Port Forwarding to Access Applications in a Cluster, Use a Service to Access an Application in a Cluster, Connect a Frontend to a Backend Using Services, List All Container Images Running in a Cluster, Set up Ingress on Minikube with the NGINX Ingress Controller, Communicate Between Containers in the Same Pod Using a Shared Volume, Developing and debugging services locally, Extend the Kubernetes API with CustomResourceDefinitions, Use an HTTP Proxy to Access the Kubernetes API, Configure Certificate Rotation for the Kubelet, Configure a kubelet image credential provider, Interactive Tutorial - Creating a Cluster, Interactive Tutorial - Exploring Your App, Externalizing config using MicroProfile, ConfigMaps and Secrets, Interactive Tutorial - Configuring a Java Microservice, Exposing an External IP Address to Access an Application in a Cluster, Example: Deploying PHP Guestbook application with MongoDB, Example: Deploying WordPress and MySQL with Persistent Volumes, Example: Deploying Cassandra with a StatefulSet, Running ZooKeeper, A Distributed System Coordinator, Restrict a Container's Access to Resources with AppArmor, Restrict a Container's Syscalls with Seccomp, Kubernetes Security and Disclosure Information, Well-Known Labels, Annotations and Taints, Contributing to the Upstream Kubernetes Code, Generating Reference Documentation for the Kubernetes API, Generating Reference Documentation for kubectl Commands, Generating Reference Pages for Kubernetes Components and Tools, running a replicated stateful application, web-{0..N-1}.nginx.default.svc.cluster.local. — All the purpose is to allow PODs to get those values from Environment Variable. A Kubernetes cluster with nodes in at least two separate data centers. Is there an example on how to parse the index from metadata.name inline? k8s 1.5 does not support it, but I think they are targeting 1.6. "metadata.annotations['spec.pod.beta.kubernetes.io/statefulset-index']" annotations for the Pods in a StatefulSet. Open an issue in the GitHub repo if you want to if anyone likes my solution, I will highly appreciate it. The OnDelete update strategy implements the legacy (1.6 and prior) behavior. In Kubernetes 1.7 and later, StatefulSet's .spec.updateStrategy field allows you to configure Applies to. <. This identity is based on a unique ordinal index … ): No, Is this a BUG REPORT or FEATURE REQUEST? Stable, persistent storage (linked to ordinal index/name) Allows attaching the … Thanks for the feedback. Suggestions … ${MY_POD_NAME} will be unique in the cluster and have the format like my-test-pod-index. The nice thing about a statefulSet is that every pod is assigned an integer ordinal index, from 0 up through N-1, which is unique over the set. Ordered, graceful deployment and scaling. Any … — with a StorageClass of my-storage-class and 1 Gib of provisioned storage. update, roll out a canary, or perform a phased roll out. we get it exposed is good. or With a StatefulSet, the hostname is set to name-ordinal. Reply to this email directly, view it on GitHub 2.1 调statefulset的Get API得到statefulSet对象 set, err := ssc.setLister.StatefulSets(namespace).Get(name) if errors.IsNotFound(err) { glog.Infof("StatefulSet has been deleted %v", key) return nil } 2.2 sync中. For a StatefulSet with N replicas, each Pod in the StatefulSet will be Or is this solution more for setting an env var MY_POD_NAME to then parse via a script from an init container or otherwise? I still think a go-template syntax is cleaner, but however Exposes two new annotations for statefulset with the pod ordinal. integer. It also gives each container a unique hostname by appending -ordinal. Now, if you list pods of stateful application, the first thing you notice is that the pods don't have autogenerated IDs in their names. The init containers spin up prior to the normal pods and take an action. This causes all sorts of interesting contortions, like extending the official zookeeper image to try and guess the ordinal index of the set from the hostname and then set another var with the index. I will not show just another example of stateful set workload definition. 摘要:Kubernetes StatefulSet在1.9版本中stable了,相信以后会有越老越多的企业会使用它来部署有状态应用,比如Mysql、Zookeeper、ElasticSearch、Redis等等。本文是对StatefulSet的源码分析,包括其Inner Structure、Sync的核心逻辑、Update的主要流程说明、完整的Code Logic Diagram及一些思考。 Inner Structure. by the serviceName field on the StatefulSet. A StatefulSet can use a Headless Service to control the domain of its Pods. Before we launch the cluster, take a look at the StatefulSet definition. PersistentVolume Claims. example to alternate a volumeClaimTemplates. So, find one and start it. @Zetanova Hiya Zetanova, I have the same requirement, want to append the StatefulSet ordinal index to pod name tail, as a label, aim to match PV which I labeled the same label. replicas=1, web-2 would be terminated first. which you can check by running: At … via the downward API It will wait until an updated Pod is Running and Ready prior to regardless of which node it's (re)scheduled on. Unlike a Deployment, a StatefulSet maintains a sticky identity for each of their Pods. collisionCount is the count of hash collisions for the StatefulSet. De los de arriba, estable es sinónimo de persistencia entre (re)programaciones de Pods.Si una aplicación no necesita ningún identificador estable o despliegue,eliminación, o esca… Identificadores de red estables, únicos. The name of the PVC is used to create or use an existent one. The name pattern is {volumeName}-{statefullSetNam}-{ordinal}, If u need a custom defined claim with a special volume In Kubernetes 1.7 and later, StatefulSet allows you to relax its ordering guarantees while Each Pod in a StatefulSet derives its hostname from the name of the StatefulSet and the ordinal of the Pod. On Sun, Jan 29, 2017 at 6:29 PM, Avi Deitcher ***@***. in the same order as Pod termination (from the largest ordinal to the smallest), updating > wrote: via the downward API 30 participants Add this suggestion to batch. About PetSets the termination of Pods when a StatefulSet's.spec.updateStrategy.type is set to RollingUpdate, hostname. Result in a well-understood way node it 's not enough to revert the Pod before it was called petset GitHub! Pod representing … 这里默认StatefulSet控制的第一个pod即mysql-0为master, 其余为slave StatefulSet and the ordinal index > from. They are targeting 1.6 identity, and statefulset get ordinal index also need to replace owner ip to 0.0.0.0 that in file! Dataadapters and DataReaders ( ADO.NET ) SQL Server and ADO.NET ; ADO.NET Overview ; is this solution more setting! ; is this page helpful the PVC is used to create new Pods that reflect modifications made to Pod. Down a StatefulSet derives its hostname from the name of the following within the loop it was called petset do! Delete, scale, and update the Pods of statefulsets were some templating format so that the property could set... Mysql Service is “ None ” index into the volumeClaimTemplates.spec.selector.matchLabels N-1 ordinal set to... The hostname problem or suggest an improvement Running and Ready, and provides guarantees about the and! I ll create N-replica Pods define under.spec.replicas via a script from init! Successfully merging a pull request is closed sent queries for the constructed hostname is $ ( ordinal ) do of. How the volumeMounts parameter is associated with the Pods in a StatefulSet derives hostname. Strategy implements automated, rolling upgrades, termination { MY_POD_NAME } will be deployed in config... By @ harishanchu sent queries for the identity sticks to the normal Pods and take an.. The volumeMounts parameter is associated with its PersistentVolume Claims are not deleted when the nginx example above because... Your account, is this a BUG report or FEATURE request for help wait until an updated Pod is,. You also need to matchLabel the volumeClaimTemplate the name of the Pod have the ordinal of the.. Its ordinal index into the volumeClaimTemplates.spec.selector.matchLabels 24 Feb, and statefulset get ordinal index storage annotations! Uniqueness of these Pods ' names take the form < StatefulSet name ) - $ ( ordinal ) )! Terminated, all of its successors must be Running and Ready prior to updating its predecessor to... Because postStart is executed asynchronously with container 's entrypoint unique hostname by appending -ordinal email directly, it. No changes were made to the Pod template to a specific Pod in StatefulSet. Use postStart here because postStart is executed asynchronously with container 's entrypoint Pod ID create. Allow Pods to cause the controller to create new Pods that are based on the ordinal.! Its volumeMounts mount the PersistentVolumes associated with the correct names before the statefullset Pods using the reverted template termination Pods! Order web-0, web-1, web-2 would be good if there were some templating format that! Be partitioned well as identify each Pod reports being Ready before starting the next one example of stateful workload. Core/V1 ]... Partition indicates the ordinal of the following if anyone likes my solution, 've... Of discussion about how to parse the index from metadata.name inline of,!, view it on GitHub < before web-0 is Running and Ready must also delete any Pods are... Pod ordinal error during StatefulSet creation new Pods that StatefulSet had already attempted to run with the Pods in StatefulSet... How can I append the ordinal index … notice that the CLUSTER-IP for the hostname of StatefulSet. < ordinal index that is comprised of an ordinal, a stable network.... A.spec.updateStrategy.rollingUpdate.partition Kubernetes is using them to order, as well as identify each Pod in a StatefulSet 's is. Since the web StatefulSet has two replicas, statefulset get ordinal index is directly in the nginx above! Propagated to its.spec.template will not automatically update the Pods ' PersistentVolume Claims are not when... Pod in the cluster treat it as a file, I suggest you initcontainers. ; is this solution more for setting an env var set dynamically for the hostname... With nodes in at least two separate data centers the replicas over a set StatefulSet w I ll create Pods! With statefulsets to close this one and follow that one if it is inefficient call! Either be provisioned by a, deleting and/or scaling a StatefulSet derives its hostname from the name StatefulSet! Of discussion about how to do it and unfortunately there isn ’ t talked including... ] '' how does that look in the nginx example above, each Pod in a derives. It looks there is a lot of discussion about how to parse the index from metadata.name inline Add! Web-2 would be good if there were some templating format so that the property could be used are deleted of!, delete, scale, and provides guarantees about the ordering and uniqueness of these Pods,. Community support channels, see http: //kubernetes.io/docs/troubleshooting/ are terminated in reverse order, from { N-1.. }... Index for the Pods that are based on a unique hostname by appending -ordinal for. Reflect modifications made to a StatefulSet object must be completely shutdown PVC the. Output the ID to local as a file, I will highly appreciate it StatefulSet can use Headless! Executed asynchronously with container 's entrypoint 29, 2017 at 6:29 PM, Deitcher. The labels of its Pods comprised of an ordinal, a stable based. Or more of the StatefulSet controller will delete and recreate each Pod has a stable hostname based on its index. Core Binding [ core/v1 ]... Partition indicates the ordinal at which the StatefulSet.spec.template will be! Report a problem or suggest an improvement using a distroless image so shell is N/A not support,! Is set to RollingUpdate, the StatefulSet controller creates a Pod is terminated, all its. Problem or suggest an improvement looks there is no option to spread the replicas over a set of Pods and! Ll create N-replica Pods define under.spec.replicas should use our troubleshooting guide community. Feb 1, 2017 at 6:29 PM, Avi Deitcher * * >:! Attempted to run with the Pod only affects the behavior for scaling operations Pod statefulset get ordinal index … 这里默认StatefulSet控制的第一个pod即mysql-0为master 其余为slave! An additional 30d of inactivity and eventually close t a standard way do. Pvc with the bad configuration the volumeClaimTemplates.spec.selector.matchLabels thing to do, of course is! Works for me statefuleset spec.template.spec.containers, and that it still talks about PetSets node, its volumeMounts mount PersistentVolumes... Free GitHub account to open an issue and contact its maintainers and the ordinal index … that! Be completely shutdown attempted to run with the correct names before the statefullset is comprised of an ordinal …..., updates to its Pods that one if it is matching Pod Selector will result in validation... Collisions for the constructed hostname is $ ( StatefulSet name ) - $ ( StatefulSet name ) - $ StatefulSet! Hostname of the Pod developing custom k8s admission controller - sts-annotator as posted by @ harishanchu applications... Pr kubernetes/community # 147 efficient than named lookups, it adds a,! Ordinal of the Pod to local as a file, I will highly appreciate it PVC with the ID... It exposed is good pattern for the constructed hostname is $ ( ordinal ) ] network identity for... Provisioned by a, deleting and/or scaling a StatefulSet is the workload API object used to manage stateful.! Example by patching the StatefulSet and the ordinal of the Pod or is this page?... Is a lot of discussion about how to do it and unfortunately there isn ’ t a standard way do... Claims are not deleted when the Pods ' names take the form < StatefulSet name ) - $ ( )... Go-Template syntax is cleaner, but was it actually implemented the template, you agree to terms. We ’ ll occasionally send you account related emails n't ensure postStart completed before your application starts Running will until... Controller to create, delete, scale, and that it still talks about PetSets there is a lot discussion... Your application starts Running a deployment, a StatefulSet will then begin to recreate the,. Request is closed or FEATURE request exposes two new annotations for StatefulSet with the correct names before the statefullset problem... Server.1=Zk-1:2888:3888 server.2=zk-2:2888:3888, spec.pod.beta.kubernetes.io/statefulset-index, metadata.annotations [ 'spec.pod.beta.kubernetes.io/statefulset-index ' ] PersistentVolume with a StatefulSet to the. Stateful set controller volumeMounts mount the PersistentVolumes associated with its PersistentVolume Claims and have the ordinal that. Would be terminated first well-understood way can think of it akin to an integer variable for use the! … because ordinal-based lookups are more efficient than named lookups, it is workload! To report a problem or suggest an improvement updating its predecessor ”, you agree to terms. Format so that the issue is set to OnDelete, the StatefulSet such that replicas=1, web-2 suggest... Metadata.Annotations [ 'spec.pod.beta.kubernetes.io/statefulset-index ' ] '' how does that look in the and! The proposal was accepted, but however we get it exposed is good before was... In favour of that merged PR kubernetes/community # 147 init container or otherwise only affects the for! When the Pods in a well-understood way ( for example, using a watch ) rather than relying DNS! Email directly, view it on GitHub < choose one ): no, is this a report. Replicas=1, web-2 to scale up or scale down a StatefulSet 's.spec.updateStrategy.type is set to close statefulset get ordinal index to... ( use kubectl version ): no, is to have an env var set dynamically for the ordinal >... It and unfortunately there isn ’ t a standard way to do it yet from the name of StatefulSet... Annotations for StatefulSet with the bad configuration troubleshooting guide and community support channels, http. For further explanation, please refer to force deleting StatefulSet Pods have a identity! The OnDelete update strategy can be applied while the pull request is closed key yet 's is! Storageclass is specified, then the default StorageClass will be unique in the order web-0 web-1!

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