Deploying reloader on Kubernetes

reloader

Plural

A Kubernetes controller to watch changes in ConfigMap and Secrets and do rolling upgrades on Pods with their associated Deployment, StatefulSet, DaemonSet and DeploymentConfig.

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# ![](assets/web/reloader-round-100px.png) RELOADER [![Go Report Card](https://goreportcard.com/badge/github.com/stakater/reloader?style=flat-square)](https://goreportcard.com/report/github.com/stakater/reloader) [![Go Doc](https://img.shields.io/badge/godoc-reference-blue.svg?style=flat-square)](http://godoc.org/github.com/stakater/reloader) [![Release](https://img.shields.io/github/release/stakater/reloader.svg?style=flat-square)](https://github.com/stakater/reloader/releases/latest) [![GitHub tag](https://img.shields.io/github/tag/stakater/reloader.svg?style=flat-square)](https://github.com/stakater/reloader/releases/latest) [![Docker Pulls](https://img.shields.io/docker/pulls/stakater/reloader.svg?style=flat-square)](https://hub.docker.com/r/stakater/reloader/) [![Docker Stars](https://img.shields.io/docker/stars/stakater/reloader.svg?style=flat-square)](https://hub.docker.com/r/stakater/reloader/) [![license](https://img.shields.io/github/license/stakater/reloader.svg?style=flat-square)](LICENSE) [![Get started with Stakater](https://stakater.github.io/README/stakater-github-banner.png)](http://stakater.com/?utm_source=Reloader&utm_medium=github) ## Problem We would like to watch if some change happens in `ConfigMap` and/or `Secret`; then perform a rolling upgrade on relevant `DeploymentConfig`, `Deployment`, `Daemonset`, `Statefulset` and `Rollout` ## Solution Reloader can watch changes in `ConfigMap` and `Secret` and do rolling upgrades on Pods with their associated `DeploymentConfigs`, `Deployments`, `Daemonsets` `Statefulsets` and `Rollouts`. ## Compatibility Reloader is compatible with kubernetes >= 1.9 ## How to use Reloader For a `Deployment` called `foo` have a `ConfigMap` called `foo-configmap` or `Secret` called `foo-secret` or both. Then add your annotation (by default `reloader.stakater.com/auto`) to main metadata of your `Deployment` ```yaml kind: Deployment metadata: annotations: reloader.stakater.com/auto: "true" spec: template: metadata: ``` This will discover deploymentconfigs/deployments/daemonsets/statefulset/rollouts automatically where `foo-configmap` or `foo-secret` is being used either via environment variable or from volume mount. And it will perform rolling upgrade on related pods when `foo-configmap` or `foo-secret`are updated. You can restrict this discovery to only `ConfigMap` or `Secret` objects that are tagged with a special annotation. To take advantage of that, annotate your deploymentconfigs/deployments/daemonsets/statefulset/rollouts like this: ```yaml kind: Deployment metadata: annotations: reloader.stakater.com/search: "true" spec: template: ``` and Reloader will trigger the rolling upgrade upon modification of any `ConfigMap` or `Secret` annotated like this: ```yaml kind: ConfigMap metadata: annotations: reloader.stakater.com/match: "true" data: key: value ``` provided the secret/configmap is being used in an environment variable, or a volume mount. Please note that `reloader.stakater.com/search` and `reloader.stakater.com/auto` do not work together. If you have the `reloader.stakater.com/auto: "true"` annotation on your deployment, then it will always restart upon a change in configmaps or secrets it uses, regardless of whether they have the `reloader.stakater.com/match: "true"` annotation or not. We can also specify a specific configmap or secret which would trigger rolling upgrade only upon change in our specified configmap or secret, this way, it will not trigger rolling upgrade upon changes in all configmaps or secrets used in a deploymentconfig, deployment, daemonset, statefulset or rollout. To do this either set the auto annotation to `"false"` (`reloader.stakater.com/auto: "false"`) or remove it altogether, and use annotations mentioned [here](#Configmap) or [here](#Secret) ### Configmap To perform rolling upgrade when change happens only on specific configmaps use below annotation. For a `Deployment` called `foo` have a `ConfigMap` called `foo-configmap`. Then add this annotation to main metadata of your `Deployment` ```yaml kind: Deployment metadata: annotations: configmap.reloader.stakater.com/reload: "foo-configmap" spec: template: metadata: ``` Use comma separated list to define multiple configmaps. ```yaml kind: Deployment metadata: annotations: configmap.reloader.stakater.com/reload: "foo-configmap,bar-configmap,baz-configmap" spec: template: metadata: ``` ### Secret To perform rolling upgrade when change happens only on specific secrets use below annotation. For a `Deployment` called `foo` have a `Secret` called `foo-secret`. Then add this annotation to main metadata of your `Deployment` ```yaml kind: Deployment metadata: annotations: secret.reloader.stakater.com/reload: "foo-secret" spec: template: metadata: ``` Use comma separated list to define multiple secrets. ```yaml kind: Deployment metadata: annotations: secret.reloader.stakater.com/reload: "foo-secret,bar-secret,baz-secret" spec: template: metadata: ``` ### NOTES - Reloader also supports [sealed-secrets](https://github.com/bitnami-labs/sealed-secrets). [Here](docs/Reloader-with-Sealed-Secrets.md) are the steps to use sealed-secrets with reloader. - For [rollouts](https://github.com/argoproj/argo-rollouts/) reloader simply triggers a change is up to you how you configure the rollout strategy. - `reloader.stakater.com/auto: "true"` will only reload the pod, if the configmap or secret is used (as a volume mount or as an env) in `DeploymentConfigs/Deployment/Daemonsets/Statefulsets` - `secret.reloader.stakater.com/reload` or `configmap.reloader.stakater.com/reload` annotation will reload the pod upon changes in specified configmap or secret, irrespective of the usage of configmap or secret. - you may override the auto annotation with the `--auto-annotation` flag - you may override the search annotation with the `--auto-search-annotation` flag and the match annotation with the `--search-match-annotation` flag - you may override the configmap annotation with the `--configmap-annotation` flag - you may override the secret annotation with the `--secret-annotation` flag - you may want to prevent watching certain namespaces with the `--namespaces-to-ignore` flag - you may want to prevent watching certain resources with the `--resources-to-ignore` flag - you can configure logging in JSON format with the `--log-format=json` option - you can configure the "reload strategy" with the `--reload-strategy=<strategy-name>` option (details below) ## Reload Strategies Reloader supports multiple "reload" strategies for performing rolling upgrades to resources. The following list describes them: - **env-vars**: When a tracked `configMap`/`secret` is updated, this strategy attaches a Reloader specific environment variable to any containers referencing the changed `configMap` or `secret` on the owning resource (e.g., `Deployment`, `StatefulSet`, etc.). This strategy can be specified with the `--reload-strategy=env-vars` argument. Note: This is the default reload strategy. - **annotations**: When a tracked `configMap`/`secret` is updated, this strategy attaches a `reloader.stakater.com/last-reloaded-from` pod template annotation on the owning resource (e.g., `Deployment`, `StatefulSet`, etc.). This strategy is useful when using resource syncing tools like ArgoCD, since it will not cause these tools to detect configuration drift after a resource is reloaded. Note: Since the attached pod template annotation only tracks the last reload source, this strategy will reload any tracked resource should its `configMap` or `secret` be deleted and recreated. This strategy can be specified with the `--reload-strategy=annotations` argument. ## Deploying to Kubernetes You can deploy Reloader by following methods: ### Vanilla Manifests You can apply vanilla manifests by changing `RELEASE-NAME` placeholder provided in manifest with a proper value and apply it by running the command given below: ```bash kubectl apply -f https://raw.githubusercontent.com/stakater/Reloader/master/deployments/kubernetes/reloader.yaml ``` By default, Reloader gets deployed in `default` namespace and watches changes `secrets` and `configmaps` in all namespaces. Reloader can be configured to ignore the resources `secrets` and `configmaps` by passing the following args (`spec.template.spec.containers.args`) to its container : | Args | Description | | -------------------------------- | -------------------- | | --resources-to-ignore=configMaps | To ignore configMaps | | --resources-to-ignore=secrets | To ignore secrets | `Note`: At one time only one of these resource can be ignored, trying to do it will cause error in Reloader. Workaround for ignoring both resources is by scaling down the reloader pods to `0`. ### Vanilla kustomize You can also apply the vanilla manifests by running the following command ```bash kubectl apply -k https://github.com/stakater/Reloader/deployments/kubernetes ``` Similarly to vanilla manifests get deployed in `default` namespace and watches changes `secrets` and `configmaps` in all namespaces. ### Kustomize You can write your own `kustomization.yaml` using ours as a 'base' and write patches to tweak the configuration. ```yaml apiVersion: kustomize.config.k8s.io/v1beta1 kind: Kustomization bases: - https://github.com/stakater/Reloader/deployments/kubernetes namespace: reloader ``` ### Helm Charts Alternatively if you have configured helm on your cluster, you can add reloader to helm from our public chart repository and deploy it via helm using below mentioned commands. Follow [this](docs/Helm2-to-Helm3.md) guide, in case you have trouble migrating reloader from Helm2 to Helm3 ```bash helm repo add stakater https://stakater.github.io/stakater-charts helm repo update helm install stakater/reloader # For helm3 add --generate-name flag or set the release name ``` **Note:** By default reloader watches in all namespaces. To watch in single namespace, please run following command. It will install reloader in `test` namespace which will only watch `Deployments`, `Daemonsets` `Statefulsets` and `Rollouts` in `test` namespace. ```bash helm install stakater/reloader --set reloader.watchGlobally=false --namespace test # For helm3 add --generate-name flag or set the release name ``` Reloader can be configured to ignore the resources `secrets` and `configmaps` by using the following parameters of `values.yaml` file: | Parameter | Description | Type | | ---------------- | -------------------------------------------------------------- | ------- | | ignoreSecrets | To ignore secrets. Valid value are either `true` or `false` | boolean | | ignoreConfigMaps | To ignore configMaps. Valid value are either `true` or `false` | boolean | `Note`: At one time only one of these resource can be ignored, trying to do it will cause error in helm template compilation. You can also set the log format of Reloader to json by setting `logFormat` to `json` in values.yaml and apply the chart You can enable to scrape Reloader's Prometheus metrics by setting `serviceMonitor.enabled` or `podMonitor.enabled` to `true` in values.yaml file. Service monitor will be removed in future releases of reloader in favour of Pod monitor. **Note:** Reloading of OpenShift (DeploymentConfig) and/or Argo Rollouts has to be enabled explicitly because it might not be always possible to use it on a cluster with restricted permissions. This can be done by changing the following parameters: | Parameter | Description | Type | | ---------------- |------------------------------------------------------------------------------| ------- | | isOpenshift | Enable OpenShift DeploymentConfigs. Valid value are either `true` or `false` | boolean | | isArgoRollouts | Enable Argo Rollouts. Valid value are either `true` or `false` | boolean | | reloadOnCreate | Enable reload on create events. Valid value are either `true` or `false` | boolean | ## Help ### Documentation You can find more documentation [here](docs) ### Have a question? File a GitHub [issue](https://github.com/stakater/Reloader/issues), or send us an [email](mailto:stakater@gmail.com). ### Talk to us on Slack Join and talk to us on Slack for discussing Reloader [![Join Slack](https://stakater.github.io/README/stakater-join-slack-btn.png)](https://slack.stakater.com/) [![Chat](https://stakater.github.io/README/stakater-chat-btn.png)](https://stakater-community.slack.com/messages/CC5S05S12) ## Contributing ### Bug Reports & Feature Requests Please use the [issue tracker](https://github.com/stakater/Reloader/issues) to report any bugs or file feature requests. ### Developing 1. Deploy Reloader. 2. Run `okteto up` to activate your development container. 3. `make build`. 4. `./Reloader` PRs are welcome. In general, we follow the "fork-and-pull" Git workflow. 1. **Fork** the repo on GitHub 2. **Clone** the project to your own machine 3. **Commit** changes to your own branch 4. **Push** your work back up to your fork 5. Submit a **Pull request** so that we can review your changes NOTE: Be sure to merge the latest from "upstream" before making a pull request! ## Changelog View our closed [Pull Requests](https://github.com/stakater/Reloader/pulls?q=is%3Apr+is%3Aclosed). ## License Apache2 © [Stakater](http://stakater.com) ## About `Reloader` is maintained by [Stakater][website]. Like it? Please let us know at <hello@stakater.com> See [our other projects][community] or contact us in case of professional services and queries on <hello@stakater.com> [website]: http://stakater.com/ [community]: https://github.com/stakater/ ## Acknowledgements - [ConfigmapController](https://github.com/fabric8io/configmapcontroller); We documented here why we re-created [Reloader](docs/Reloader-vs-ConfigmapController.md)

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Deploying reloader on Kubernetes

Use Plural to deploy and manage reloader on Kubernetes, in your cloud.

reloader

Why Plural?

Open source

Deploy on Kubernetes

No vendor lock-in

Day 2 operations

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Deploying reloader on Kubernetes

Use Plural to deploy and manage reloader on Kubernetes, in your cloud.

reloader

Why Plural?

Open source

Deploy on Kubernetes

No vendor lock-in

Day 2 operations

You might also like...

argo-cd

argo-workflows

bootstrap-cluster-api

bytebase

Product

Company

Resources

Contact

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