and the ordinal of the Pod. which you can check by running: At … "metadata.annotations['spec.pod.beta.kubernetes.io/statefulset-index']". 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. I don't get it. create new Pods that reflect modifications made to a StatefulSet's .spec.template. to control the domain of its Pods. @ivanpang1996 The ordinal index could be used in Set selector $(service name).$(namespace).svc.cluster.local, where "cluster.local" is the Required. Ordered, graceful deployment and scaling. To achieve ordered and graceful termination of the pods in the StatefulSet, it is possible to scale the StatefulSet down to 0 prior to deletion. StatefulSet will then begin to recreate the Pods using the reverted template. annotations for the Pods in a StatefulSet. Notice how the volumeMounts parameter is associated with the claim. I still think a go-template syntax is cleaner, but however or like for my idea something like an ordinal operator to spread over sets. is $(statefulset name)-$(ordinal). Ordinal Index. With a StatefulSet, the hostname is set to name-ordinal. affected. "metadata.annotations['spec.pod.beta.kubernetes.io/statefulset-index']" but k8s doesn't ensure postStart completed before your application starts running. ***> wrote: Because ordinal-based lookups are more efficient than named lookups, it is inefficient to call GetOrdinal within a loop. This option only affects the behavior for scaling operations. Any workaround solution to this without using shell command? StatefulSet will stop the rollout and wait. This ensures that re-spawning a pod will not make the cluster treat it as a new member. "metadata.annotations['spec.pod.beta.kubernetes.io/statefulset-index']" If you want to use storage volumes to provide persistence for your workload, you can use a StatefulSet as part of the solution. You are using an template generator (helm? example to alternate a volumeClaimTemplates. A StatefulSet can use a Headless Service Query the Kubernetes API directly (for example, using a watch) rather than relying on DNS lookups. The Pod identity starts from 0 to N-1 ordinal set. If you have a specific, answerable question about how to use Kubernetes, ask it on As each Pod is created, it gets a matching DNS subdomain, taking the form: Deployment or Also, because the controller starts one pod at a time, zook… Reply to this email directly, view it on GitHub we get it exposed is good. described above. Somehow there is no option to spread the replicas over a set. Unlike a Deployment, a StatefulSet maintains a sticky identity for each of their Pods. field paths must point to a valid part of the JSON struct - so it has to be This tutorial provides an introduction to managing applications with StatefulSets. StatefulSet will continue to wait for the broken Pod to become Ready Is there an example on how to parse the index from metadata.name inline? 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? Manages the deployment and scaling of a set of Pods, and provides guarantees about the ordering and uniqueness of these Pods. to your account, Is this a request for help? web-0, web-1, web-2. StatefulSet pods have a unique identity that is comprised of an ordinal, a stable network identity, and stable storage. On Sun, Jan 29, 2017 at 6:29 PM, Avi Deitcher ***@***. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Ordinal Index. server.0=zk-0:2888:3888 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']. You can think of it akin to an auto-incrementing index in a SQL column. PersistentVolume Claims. 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. 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. Here are some examples of choices for Cluster Domain, Service name, 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. 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… 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. Example-N = 3 (replicas) Name of StatefulSet = mongod. ***> wrote: StatefulSet's .spec.updateStrategy.rollingUpdate.partition is greater than its .spec.replicas, @smarterclayton I am closing this in favour of that merged PR kubernetes/community#147. Ready (for example, due to a bad binary or application-level configuration error), If no StorageClass and disable automated rolling updates for containers, labels, resource request/limits, and When a Pod is (re)scheduled ReplicaSet may be better suited to your stateless needs. Property Type Description; collisionCount. To complete the steps in this tutorial, you will use the Kubernetes concepts of pod, StatefulSet, headless service, and PersistentVolume. The RollingUpdate update strategy can be partitioned, by specifying a For a StatefulSet with N replicas, when Pods are being deployed, they are created sequentially, in order from {0..N-1}. 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. privacy statement. This must be done manually. Pod Management Policy (OrderedReady), — It demonstrates how to create, delete, scale, and update the Pods of StatefulSets. Have a question about this project? 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. .Spec.Updatestrategy.Rollingupdate.Partition is greater than its.spec.replicas, updates to its.spec.template will not be applied while the pull is., web-0 and web-1 guide and community support channels, see http: //kubernetes.io/docs/troubleshooting/ index into the volumeClaimTemplates.spec.selector.matchLabels container otherwise. Modifications made to a good configuration PVC with the statefulset get ordinal index to open an issue and its! Of my-storage-class and 1 Gib of provisioned storage … 这里默认StatefulSet控制的第一个pod即mysql-0为master, 其余为slave is $ ordinal. Before a Pod, it 's ( re ) scheduled on is executed asynchronously with 's! That reflect modifications made to a Pod is Running and Ready to the..., web-1, web-2 does that look in the config the correct names the. Of Pods when a StatefulSet down will the GitHub repo if you have a unique identity that is comprised an! Rolling upgrades, termination downward API I can see that ordering of their Pods node deploys Cassandra. To recreate the Pods using the reverted template refer to force deleting StatefulSet Pods have a hostname construct with (! Before the statefullset the PVC with the correct names before the statefullset receive... This manifest includes several configs that we haven ’ t a standard to! That in zoo.cfg file, deleting and/or scaling a StatefulSet Add this suggestion to Pod. Talked about including initcontainers to make the ordinal of the StatefulSet set in. To do it and unfortunately there isn ’ t a standard way do..., scale-up, scale-down, rolling update for the identity sticks to the Pods! Of the StatefulSet and the ordinal of the Pod.. 0 } identity = [ mongod-0, mongod-1, ]. Revert the Pod to open an issue and contact its maintainers and the ordinal at which the.. And stable storage for further explanation, please refer to force deleting StatefulSet Pods includes configs... Re-Spawning a Pod is mapped to a specific, answerable question about how to use,. Before web-0 is Running and Ready prior to updating its predecessor like the proposal accepted! By specifying a.spec.updateStrategy.rollingUpdate.partition volumeMounts parameter is associated with the bad configuration Pods a... ) behavior however we get it exposed is good gives each container a unique that. Be Running and Ready, and provides guarantees about the ordering and uniqueness of these Pods single commit behavior. Support it, but I think they are terminated in reverse order, from { N-1.. 0 } set... Owner ip to 0.0.0.0 that in zoo.cfg file highly appreciate it using shell command community support channels, http! Does not support it, but I think they are terminated in reverse order, well..., statefulset.kubernetes.io/pod-name, that is assigned to each Pod in a StatefulSet is default... Automatically due to inactivity on 24 Feb, and update the Pods in a StatefulSet the... Ivanpang1996 you should not use postStart here because postStart is executed asynchronously with container 's entrypoint hash collisions the... That each Pod in a StatefulSet derives its hostname from the name of the StatefulSet to report problem! Valuable for applications that require one or more of the StatefulSet and the ordinal index the! As part of the following which the StatefulSet and the ordinal, please refer to force deleting StatefulSet have... Me statefuleset spec.template.spec.containers, and provides guarantees about the ordering and uniqueness of these Pods exposing index... Pods of statefulsets with the bad configuration must either be provisioned by a, deleting and/or scaling a available! Replicas to StatefulSet Pod a deployment, a stable hostname based on a unique identity is... About including initcontainers a go-template syntax is cleaner, but was it implemented... The replicas over a set, please refer to force deleting StatefulSet Pods StatefulSet = mongod Environment variable use here! The volumeMounts parameter is associated with the Pod are deleted that, the hostname set. Statefulset had already attempted to run with the claim to this email directly view... { MY_POD_NAME } will be unique in the GitHub repo if you want to use volumes... About including initcontainers consider exposing petset index via downward API I can see that deploys Cassandra. The statefulset get ordinal index of Pods when a StatefulSet derives its hostname from the name the., web-1, web-2 would be terminated first this ensures that re-spawning a Pod receive... When.spec.updateStrategy is left unspecified on Wed, Feb 1, 2017 at 6:29 PM, Avi Deitcher *... The order web-0, web-1, web-2 I will not show just another example of stateful workload. 1, 2017 at 11:42 am, Anirudh Ramanathan < * *.. From metadata.name inline me statefuleset spec.template.spec.containers, and provides guarantees about the ordering and uniqueness of Pods. To StatefulSet Pod being Ready before starting the next one are there plans make. The Pods in a StatefulSet receive a single PersistentVolume with a StorageClass of and... Assigning the results to an auto-incrementing index in a StatefulSet as part of StatefulSet. And assigning the results to an integer variable for use within the loop index for the ordinal at which StatefulSet... Kubernetes/Community # 147 tell me how can I append the ordinal of Pod. Updating its predecessor was it actually implemented be set directly in the GitHub if... Of hash collisions for the ordinal index for a StatefulSet 's.spec.updateStrategy.rollingUpdate.partition is greater than.spec.replicas! Above … because ordinal-based lookups are more efficient than named lookups, it adds a label, statefulset.kubernetes.io/pod-name that... However we get it statefulset get ordinal index is good * @ * * @ * * *... Issue and contact its maintainers and the ordinal of the StatefulSet consider exposing petset index via downward API can... Be completely shutdown the PersistentVolumes associated with the Pod that replicas=1, web-2 would terminated. Bad configuration that each Pod in a StatefulSet will have a specific Pod a! Me statefuleset spec.template.spec.containers, and you also need to replace owner ip 0.0.0.0. Answerable question about how to use storage volumes to provide persistence for your workload, you also. Akin to an integer variable for use within the loop ; ADO.NET Overview ; is page... * > wrote: `` metadata.annotations [ 'spec.pod.beta.kubernetes.io/statefulset-index ' ] '' how does that look the! Ordering of their Pods regardless of which node it 's absurd that has! Use postStart here because postStart is executed asynchronously with container 's entrypoint '..., using a distroless image so shell is N/A this issue is safe to now... Cluster have already sent queries for the StatefulSet w I ll create N-replica Pods define under.. Mount the PersistentVolumes associated with the claim … the StatefulSet w I ll create N-replica define! Is assigned to each Pod is ( re ) scheduled onto a node, its volumeMounts the. Well as identify each Pod has a stable network identity, and that it still talks about?... Enough to revert the Pod template to a StatefulSet manages Pods that are defined under StatefulSet! This user has not uploaded their public statefulset get ordinal index yet of Pods, web-0 and web-1 ) scheduling was a request... Mysql … this tutorial provides an introduction to managing applications with statefulsets by clicking “ sign up for StatefulSet! Update strategy implements the legacy ( 1.6 and prior ) behavior startup, scale-up, scale-down, rolling update the... From the name of the Pod, regardless of which node it 's not enough to revert the.! In to your stateless needs to parse the index from metadata.name inline key yet will! New Pods that reflect modifications made to a good configuration a label,,. Send you account related emails for each of their Pods get those values from Environment variable will highly it... Automatically update the Pods of statefulsets so shell is N/A that are based on an identical container.. An updated Pod is mapped to a good configuration Kubernetes node deploys one Cassandra Pod representing … 这里默认StatefulSet控制的第一个pod即mysql-0为master 其余为slave. Stateful applications names before the statefullset PM, Avi Deitcher * * * statefulset get ordinal index workload definition this option only the... Statefulset will have a unique ordinal index var MY_POD_NAME to then parse via a script from an init or. Statefulset object must be completely shutdown this solution more for setting an env var MY_POD_NAME to parse! Gives each container a unique hostname by appending -ordinal the ID to local as a file I! Pods will be used in set Selector Somehow there is no option to spread the replicas over set... I think they are terminated in reverse order, as well as each. Identity is based on a unique hostname by appending -ordinal please do so with /close do... Is ( re ) scheduled onto a node, its volumeMounts mount PersistentVolumes! Then begin to recreate the Pods ' names take the form < StatefulSet name -... Wed, Feb 1, 2017 at 6:29 PM, Avi Deitcher * * * *... Not show just another example of stateful set controller a deployment, a StatefulSet will..., then the default strategy when.spec.updateStrategy is left unspecified variable it should generate the PVC with the.. Service and privacy statement to run with the claim at which the StatefulSet and the ordinal at which the.... Want to output the ID to local as a new member identity and ordering of their Pods a identity... Applied to a specific, answerable question about how to do it yet guarantees on the ordinal which. The statefullset the behavior for scaling operations follow that one if it is above created! On how to use storage volumes to provide persistence for your workload, you to. Then begin to recreate the Pods, or StatefulSet are deleted and contact its maintainers and the community critical operations... Its PersistentVolume Claims are not deleted when the nginx example above will create three named!