Adds docs on using Scheduler with Ephemeral storage (#4306)

Signed-off-by: joshvanl <me@joshvanl.dev>

daprdocs/content/en/developing-applications/building-blocks/jobs/jobs-overview.md

@@ -16,11 +16,6 @@ Jobs in Dapr consist of:
 
 [See example scenarios.]({{< ref "#scenarios" >}})
 
-{{% alert title="Warning" color="warning" %}}
-By default, job data is not resilient to [Scheduler]({{< ref scheduler.md >}}) service restarts.
-A persistent volume must be provided to Scheduler to ensure job data is not lost in either [Kubernetes]({{< ref kubernetes-persisting-scheduler.md >}}) or [Self-hosted]({{< ref self-hosted-persisting-scheduler.md >}}) mode.
-{{% /alert %}}
-
 <img src="/images/scheduler/scheduler-architecture.png" alt="Diagram showing the Scheduler control plane service and the jobs API">
 
 ## How it works

daprdocs/content/en/operations/hosting/kubernetes/kubernetes-persisting-scheduler.md

@@ -6,12 +6,15 @@ weight: 50000
 description: "Configure Scheduler to persist its database to make it resilient to restarts"
 ---
 
-The [Scheduler]({{< ref scheduler.md >}}) service is responsible for writing jobs to its embedded database and scheduling them for execution.
+The [Scheduler]({{< ref scheduler.md >}}) service is responsible for writing jobs to its embedded Etcd database and scheduling them for execution.
-By default, the Scheduler service database writes this data to an in-memory ephemeral tempfs volume, meaning that **this data is not persisted across restarts**. Job data will be lost during these events.
+By default, the Scheduler service database writes this data to a Persistent Volume Claim of 1Gb of size using the cluster's default [storage class](https://kubernetes.io/docs/concepts/storage/storage-classes/). This means that there is no additional parameter required to run the scheduler service reliably on most Kubernetes deployments, although you will need additional configuration in some deployments or for a production environment.
 
-To make the Scheduler data resilient to restarts, a persistent volume must be mounted to the Scheduler `StatefulSet`.
+## Production Setup
-This persistent volume is backed by a real disk that is provided by the hosted Cloud Provider or Kubernetes infrastructure platform.
+
-Disk size is determined by how many jobs are expected to be persisted at once; however, 64Gb should be more than sufficient for most use cases.
+In case your Kubernetes deployment does not have a default storage class or you are configuring a production cluster, defining a storage class is required.
+
+A persistent volume is backed by a real disk that is provided by the hosted Cloud Provider or Kubernetes infrastructure platform.
+Disk size is determined by how many jobs are expected to be persisted at once; however, 64Gb should be more than sufficient for most production scenarios.
 Some Kubernetes providers recommend using a [CSI driver](https://kubernetes.io/docs/concepts/storage/volumes/#csi) to provision the underlying disks.
 Below are a list of useful links to the relevant documentation for creating a persistent disk for the major cloud providers:
 - [Google Cloud Persistent Disk](https://cloud.google.com/compute/docs/disks)
@@ -23,7 +26,7 @@ Below are a list of useful links to the relevant documentation for creating a pe
 - [Alibaba Cloud Disk Storage](https://www.alibabacloud.com/help/ack/ack-managed-and-ack-dedicated/user-guide/create-a-pvc)
 
 
-Once the persistent volume class is available, you can install Dapr using the following command, with Scheduler configured to use the persistent volume class (replace `my-storage-class` with the name of the storage class):
+Once the storage class is available, you can install Dapr using the following command, with Scheduler configured to use the storage class (replace `my-storage-class` with the name of the storage class):
 
 {{% alert title="Note" color="primary" %}}
 If Dapr is already installed, the control plane needs to be completely [uninstalled]({{< ref dapr-uninstall.md >}}) in order for the Scheduler `StatefulSet` to be recreated with the new persistent volume.
@@ -53,3 +56,37 @@ helm upgrade --install dapr dapr/dapr \
 
 {{% /codetab %}}
 {{< /tabs >}}
+
+## Ephemeral Storage
+
+Scheduler can be optionally made to use Ephemeral storage, which is in-memory storage which is **not** resilient to restarts, i.e. all Job data will be lost after a Scheduler restart.
+This is useful for deployments where storage is not available or required, or for testing purposes.
+
+{{% alert title="Note" color="primary" %}}
+If Dapr is already installed, the control plane needs to be completely [uninstalled]({{< ref dapr-uninstall.md >}}) in order for the Scheduler `StatefulSet` to be recreated without the persistent volume.
+{{% /alert %}}
+
+{{< tabs "Dapr CLI" "Helm" >}}
+ <!-- Dapr CLI -->
+{{% codetab %}}
+
+```bash
+dapr init -k --set dapr_scheduler.cluster.inMemoryStorage=true
+```
+
+{{% /codetab %}}
+
+ <!-- Helm -->
+{{% codetab %}}
+
+```bash
+helm upgrade --install dapr dapr/dapr \
+--version={{% dapr-latest-version short="true" %}} \
+--namespace dapr-system \
+--create-namespace \
+--set dapr_scheduler.cluster.inMemoryStorage=true \
+--wait
+```
+
+{{% /codetab %}}
+{{< /tabs >}}

daprdocs/content/en/reference/api/jobs_api.md

@@ -10,11 +10,6 @@ weight: 1300
 The jobs API is currently in alpha.
 {{% /alert %}}
 
-{{% alert title="Warning" color="warning" %}}
-By default, job data is not resilient to [Scheduler]({{< ref scheduler.md >}}) service restarts.
-A persistent volume must be provided to Scheduler to ensure job data is not lost in either [Kubernetes]({{< ref kubernetes-persisting-scheduler.md >}}) or [Self-Hosted]({{< ref self-hosted-persisting-scheduler.md >}}) mode.
-{{% /alert %}}
-
 With the jobs API, you can schedule jobs and tasks in the future.
 
 > The HTTP APIs are intended for development and testing only. For production scenarios, the use of the SDKs is strongly