Common storage backend docs

docs/sources/operators-guide/configure/about-configurations.md

@@ -17,6 +17,36 @@ A given configuration loads at startup and cannot be modified at runtime. Howeve
 
 To see the current configuration state of any component, use the [`/config`]({{< relref "../reference-http-api/index.md#configuration" >}}) or [`/runtime_config`]({{< relref "../reference-http-api/index.md#runtime-configuration" >}}) HTTP API endpoint.
 
+## Common configurations
+
+Some configurations, such as object storage backend, are repeated for multiple components.
+To avoid the repetition in the configuration file, use the [`common`]({{< relref "../configure/reference-configuration-parameters/index.md#common" >}}) configuration section or `-common.*` CLI flags.
+Common configurations are first applied to all the specific configurations, which allows them to be overridden later by specific values.
+
+For example, the following configuration uses the same Amazon S3 object storage bucket called `mimir`. The common storage is located in the `us-east` region for both ruler and alertmanager stores, and the blocks storage uses the `mimir-blocks` bucket from the same region:
+
+```yaml
+common:
+  storage:
+    backend: s3
+    s3:
+      region: us-east
+      bucket_name: mimir
+
+blocks_storage:
+  s3:
+    bucket_name: mimir-blocks
+```
+
+For a reference of this configuration, see [object storage configuration reference ]({{< relref "configure-object-storage-backend.md" >}}).
+
+The precedence of the common configuration is as follows, where each configuration overrides the previous one:
+
+- YAML common values
+- YAML specific values
+- CLI common flags
+- CLI specific flags
+
 ## Operational considerations
 
 Use a single configuration file, and either pass it to all replicas of Grafana Mimir (when running multiple single-process Mimir replicas) or to all components of Grafana Mimir (when running Grafana Mimir as microservices). When running Grafana Mimir on Kubernetes, you can achieve this by storing the configuration file in a [ConfigMap](https://kubernetes.io/docs/concepts/configuration/configmap/) and mounting it in each Grafana Mimir container.

docs/sources/operators-guide/configure/configure-object-storage-backend.md

@@ -0,0 +1,50 @@
+---
+title: "Configure Grafana Mimir object storage backend"
+menuTitle: "Configure object storage"
+description: "Learn how to configure Grafana Mimir to use different object storage backend implementations."
+weight: 70
+---
+
+# Configure Grafana Mimir object storage backend
+
+Grafana Mimir can use different object storage services to persist blocks containing the metrics data, as well as recording rules and alertmanager state.
+The supported backends are:
+
+- [Amazon S3](https://aws.amazon.com/s3/) (and compatible implementations like [MinIO](https://min.io/))
+- [Google Cloud Storage](https://cloud.google.com/storage)
+- [Azure Blob Storage](https://azure.microsoft.com/es-es/services/storage/blobs/)
+- [Swift (OpenStack Object Storage)](https://wiki.openstack.org/wiki/Swift)
+
+Additionally, a file system emulated [`filesystem`]({{< relref "../configure/reference-configuration-parameters/index.md#filesystem_storage_backend" >}}) object storage implementation can be also used for testing purposes (it's not recommended for production workloads).
+
+[Ruler and alertmanager support a `local` implementation]({{< relref "../architecture/components/ruler/index.md#local-storage" >}}), which is similar to `filesystem` in the way that it uses the local file system, but it is a read-only data source and can be used to provision state into those components.
+
+## Common configuration
+
+The [common configuration]({{< relref "about-configurations.md#common-configurations" >}}) can be used to avoid repetition by filling the [`common`]({{< relref "../configure/reference-configuration-parameters/index.md#common" >}}) configuration block or by providing the `-common.storage.*` CLI flags.
+
+Note that blocks storage can't be located in the same path of the same bucket as the ruler and alertmanager stores, so when using the common configuration, [`blocks_storage`]({{< relref "../configure/reference-configuration-parameters/index.md#blocks_storage" >}}) should either:
+
+- use a different bucket, overriding the common bucket name
+- use a storage prefix
+
+Grafana Mimir will fail to start if blocks storage is configured to use the same bucket and storage prefix as alertmanager or ruler store.
+
+A valid configuration for the object storage (taken from the ["Play with Grafana Mimir" tutorial](https://grafana.com/tutorials/play-with-grafana-mimir/)) would be:
+
+```yaml
+common:
+  storage:
+    backend: s3
+    s3:
+      endpoint: minio:9000
+      access_key_id: mimir
+      secret_access_key: supersecret
+      insecure: true
+      bucket_name: mimir
+
+blocks_storage:
+  storage_prefix: blocks
+```
+
+> **Note**: If you're using a mix of YAML files and CLI flags, pay attention to the [precedence logic]({{< relref "about-configurations.md#common-configurations" >}}) of those.