92 lines
6.5 KiB
Markdown
92 lines
6.5 KiB
Markdown
# Installing the KEDA HTTP Add-on
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The HTTP Add-on is highly modular and, as expected, builds on top of KEDA core. Below are some additional components:
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- **Operator** - watches for `HTTPScaledObject` CRD resources and creates necessary backing Kubernetes resources (e.g. `Deployment`s, `Service`s, `ScaledObject`s, and so forth)
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- **Scaler** - communicates scaling-related metrics to KEDA. By default, the operator will install this for you as necessary.
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- **Interceptor** - a cluster-internal proxy that proxies incoming HTTP requests, communicating HTTP queue size metrics to the scaler, and holding requests in a temporary request queue when there are not yet any available app `Pod`s ready to serve. By default, the operator will install this for you as necessary.
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>There is [pending work](https://github.com/kedacore/http-add-on/issues/354) that may eventually make this component optional.
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## Before You Start: Cluster-global vs. Namespaced Installation
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Both KEDA and the HTTP Add-on can be installed in either cluster-global or namespaced mode. In the former case, your `ScaledObject`s and `HTTPScaledObject`s (respectively) can be installed in any namespace, and one installation will detect and process it. In the latter case, you must install your `ScaledObject`s and `HTTPScaledObject`s in a specific namespace.
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You have the option of installing KEDA and the HTTP Add-on in either mode, but if you install one as cluster-global, the other must also be cluster-global. Similarly, if you install one as namespaced, the also must also be namespaced in the same namespace.
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## Installing KEDA
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Before you install any of these components, you need to install KEDA. Below are simplified instructions for doing so with [Helm](https://helm.sh), but if you need anything more customized, please see the [official KEDA deployment documentation](https://keda.sh/docs/2.0/deploy/). If you need to install Helm, refer to the [installation guide](https://helm.sh/docs/intro/install/).
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>This document will rely on environment variables such as `${NAMESPACE}` to indicate a value you should customize and provide to the relevant command. In the below `helm install` command, `${NAMESPACE}` should be the namespace you'd like to install KEDA into.
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```console
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helm repo add kedacore https://kedacore.github.io/charts
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helm repo update
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helm install keda kedacore/keda --namespace ${NAMESPACE} --create-namespace
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```
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>The above command installs KEDA in cluster-global mode. Add `--set watchNamespace=<target namespace>` to install KEDA in namespaced mode.
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## Install the Add-on via Helm Chart
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The Helm chart for this project is within KEDA's default helm repository at [kedacore/charts](http://github.com/kedacore/charts), you can install it by running:
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```console
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helm install http-add-on kedacore/keda-add-ons-http --namespace ${NAMESPACE}
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```
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>The above command installed the HTTP Add-on in cluster-global mode. Add `--set operator.watchNamespace=<target namespace>` to install the HTTP Add-on in namepaced mode. If you do this, you must also install KEDA in namespaced mode and use the same target namespace.
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>Installing the HTTP Add-on won't affect any running workloads in your cluster. You'll need to install an `HTTPScaledObject` for each individual `Deployment` you want to scale. For more on how to do that, please see the [walkthrough](./walkthrough.md).
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### Customizing the Installation
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There are a few values that you can pass to the above `helm install` command by including `--set NAME=VALUE` on the command line.
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- `images.operator` - the name of the operator's Docker image, not including the tag. Defaults to [`ghcr.io/kedacore/http-add-on-operator`](https://github.com/kedacore/http-add-on/pkgs/container/http-add-on-operator).
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- `images.scaler` - the name of the scaler's Docker image, not including the tag. Defaults to [`ghcr.io/kedacore/http-add-on-scaler`](https://github.com/kedacore/http-add-on/pkgs/container/http-add-on-scaler).
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- `images.interceptor` - the name of the interceptor's Docker image, not including the tag. Defaults to [`ghcr.io/kedacore/http-add-on-interceptor`](https://github.com/kedacore/http-add-on/pkgs/container/http-add-on-interceptor).
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- `images.tag` - the tag to use for all the above docker images. Defaults to the [latest stable release](https://github.com/kedacore/http-add-on/releases).
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>If you want to install the latest build of the HTTP Add-on, set `version` to `canary`:
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```console
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helm install http-add-on kedacore/keda-add-ons-http --create-namespace --namespace ${NAMESPACE} --set images.tag=canary
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```
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For an exhaustive list of configuration options, see the official HTTP Add-on chart [values.yaml file](https://github.com/kedacore/charts/blob/master/http-add-on/values.yaml).
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### A Note for Developers and Local Cluster Users
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Local clusters like [Microk8s](https://microk8s.io/) offer in-cluster image registries. These are popular tools to speed up and ease local development. If you use such a tool for local development, we recommend that you use and push your images to its local registry. When you do, you'll want to set your `images.*` variables to the address of the local registry. In the case of MicroK8s, that address is `localhost:32000` and the `helm install` command would look like the following:
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```console
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helm repo add kedacore https://kedacore.github.io/charts
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helm repo update
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helm pull kedacore/keda-add-ons-http --untar --untardir ./charts
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helm upgrade kedahttp ./charts/keda-add-ons-http \
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--install \
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--namespace ${NAMESPACE} \
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--create-namespace \
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--set image=localhost:32000/keda-http-operator \
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--set images.scaler=localhost:32000/keda-http-scaler \
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--set images.interceptor=localhost:32000/keda-http-interceptor
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```
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## Compatibility Table
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| HTTP Add-On version | KEDA version | Kubernetes version |
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|---------------------|-------------------|--------------------|
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| main | v2.16 | v1.30 - v1.32 |
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| 0.10.0 | v2.16 | v1.30 - v1.32 |
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| 0.9.0 | v2.16 | v1.29 - v1.31 |
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| 0.8.0 | v2.14 | v1.27 - v1.29 |
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| 0.7.0 | v2.13 | v1.27 - v1.29 |
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| 0.6.0 | v2.12 | v1.26 - v1.28 |
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| 0.5.1 | v2.10 | v1.24 - v1.26 |
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| 0.5.0 | v2.9 | v1.23 - v1.25 |
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## Next Steps
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Now that you're finished installing KEDA and the HTTP Add-on, please proceed to the [walkthrough](./walkthrough.md) to test out your new installation.
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[Go back to landing page](./)
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