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Faizan Ahmad
3030ddebf1
* Add How it works doc * Update How-it-works.md * Update how it works * Add how it works reference in Readme
128 lines
3.9 KiB
Markdown
128 lines
3.9 KiB
Markdown
# RELOADER
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## Problem
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We would like to watch if some change happens in `ConfigMap` and `Secret` objects and then perform rolling upgrade on relevant `Deployment`, `Deamonset` and `Statefulset`
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## Solution
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Reloader can watch changes in `ConfigMap` and `Secret` and do rolling upgrades on Pods with their associated `Deployments`, `Deamonsets` and `Statefulsets`.
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**NOTE:** This controller has been inspired from [configmapController](https://github.com/fabric8io/configmapcontroller)
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## How to use Reloader
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For a `Deployment` called `foo` have a `ConfigMap` called `foo`. Then add this annotation to your `Deployment`
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```yaml
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metadata:
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annotations:
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configmap.reloader.stakater.com/reload: "foo"
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```
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OR
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For a `Deployment` called `foo` have a `Secret` called `foo`. Then add this annotation to your `Deployment`
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```yaml
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metadata:
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annotations:
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secret.reloader.stakater.com/reload: "foo"
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```
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## How Reloader works
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Then, providing `Reloader` is running, whenever you edit the `ConfigMap` or `Secret` called `foo` the Reloader will update the `Deployment` by adding the environment variable:
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```
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STAKATER_FOO_CONFIGMAP=${reloaderRevisionHash}
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```
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Or if the change is detected in secret
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```
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STAKATER_FOO_SECRET=${reloaderRevisionHash}
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```
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`reloaderRevisionHash` is the change in secret or configmap that is converted into SHA1. This value gets updated every time when reloader detects any change.
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This then triggers a rolling upgrade of your deployment's pods to use the new configuration.
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Same procedure can be followed to perform rolling upgrade on `Deamonsets` and `Statefulsets` as well.
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_Please refer to [this](docs/How-it-works.md) document for detailed working of reloader_.
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## Deploying to Kubernetes
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You can deploy Reloader by following methods:
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### Vanilla Manifests
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You can apply vanilla manifests by running the following command
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```bash
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kubectl apply -f https://raw.githubusercontent.com/stakater/Reloader/master/deployments/kubernetes/reloader.yaml
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```
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### Helm Charts
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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
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```bash
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helm repo add stakater https://stakater.github.io/stakater-charts
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helm repo update
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helm install stakater/reloader
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```
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## Monitor All namespaces
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By default Reloader gets deployed in `default` namespace and watches changes `secrets` and `configmaps` in all namespaces.
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## Help
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**Got a question?**
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File a GitHub [issue](https://github.com/stakater/Reloader/issues), or send us an [email](mailto:stakater@gmail.com).
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### Talk to us on Slack
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Join and talk to us on the #tools-imc channel for discussing Reloader
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[](https://stakater-slack.herokuapp.com/)
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[](https://stakater.slack.com/messages/CAN960CTG/)
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## Contributing
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### Bug Reports & Feature Requests
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Please use the [issue tracker](https://github.com/stakater/Reloader/issues) to report any bugs or file feature requests.
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### Developing
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PRs are welcome. In general, we follow the "fork-and-pull" Git workflow.
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1. **Fork** the repo on GitHub
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2. **Clone** the project to your own machine
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3. **Commit** changes to your own branch
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4. **Push** your work back up to your fork
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5. Submit a **Pull request** so that we can review your changes
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NOTE: Be sure to merge the latest from "upstream" before making a pull request!
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## Changelog
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View our closed [Pull Requests](https://github.com/stakater/Reloader/pulls?q=is%3Apr+is%3Aclosed).
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## License
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Apache2 © [Stakater](http://stakater.com)
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## About
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`Reloader` is maintained by [Stakater][website]. Like it? Please let us know at <hello@stakater.com>
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See [our other projects][community]
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or contact us in case of professional services and queries on <hello@stakater.com>
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[website]: http://stakater.com/
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[community]: https://github.com/stakater/
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