By default, workloads running on one Google Distributed Cloud node cannot access the local storage of another Distributed Cloud node. However, you can configure Google Distributed Cloud to use [Rakuten Symcloud Storage](https://symphony.rakuten.com/insight/datasheet/symcloud-storage), which is a third-party solution that acts as a local storage abstraction layer on each Distributed Cloud node and makes its local storage available to workloads running on other Distributed Cloud nodes. Symcloud Storage is deployed from Google Cloud Marketplace and is subject to the terms stated therein. Google provides limited support for using Symcloud Storage with Distributed Cloud and might engage the third-party provider for assistance. Software updates for Symcloud Storage are included in the Distributed Cloud software updates. ## Symcloud Storage classes This section describe the storage classes that Symcloud Storage can enable on your Distributed Cloud cluster. Symcloud Storage on Distributed Cloud does not support the `robin-rwx` storage class nor any custom-configured RWX file system mode volumes. For more information on Symcloud Storage classes, see [Using Robin CNS in Kubernetes](https://docs.robin.io/storage/1.5.1/storage.html). ### `robin` storage class The `robin` storage class is a basic Read Write-Once (RWO) storage class. The following example illustrates the instantiation of the class: apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: robin labels: app.kubernetes.io/instance: robin app.kubernetes.io/managed-by: robin.io app.kubernetes.io/name: robin provisioner: robin reclaimPolicy: Delete allowVolumeExpansion: true volumeBindingMode: WaitForFirstConsumer > [!WARNING] > **Warning:** Using this single-replica storage class can result in **loss of data** as it doesn't provide redundancy in case of node failure. We strongly recommend that you use a storage class that provides redundancy with at least three replicas. ### `robin-immediate` storage class The `robin-immediate` storage class is the same as `robin` except that the persistent volume is created immediately after creating the corresponding persistent volume claim. The following example illustrates the instantiation of the class: apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: robin-immediate labels: app.kubernetes.io/instance: robin app.kubernetes.io/managed-by: robin.io app.kubernetes.io/name: robin provisioner: robin reclaimPolicy: Delete allowVolumeExpansion: true volumeBindingMode: Immediate > [!WARNING] > **Warning:** Using this single-replica storage class can result in **loss of data** as it doesn't provide redundancy in case of node failure. We strongly recommend that you use a storage class that provides redundancy with at least three replicas. ### `robin-repl-3` storage class The `robin-repl-3` is an RWO storage class with three replicas that span across multiple Distributed Cloud nodes. The following example illustrates the instantiation of the class: apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: robin-repl-3 labels: app.kubernetes.io/instance: robin app.kubernetes.io/managed-by: robin.io app.kubernetes.io/name: robin provisioner: robin reclaimPolicy: Delete allowVolumeExpansion: true volumeBindingMode: WaitForFirstConsumer parameters: replication: "3" faultdomain: host ## Prerequisites Before you begin, complete the following steps: 1. [Configure logging and monitoring](https://docs.cloud.google.com/distributed-cloud/connected/1.5.1/docs/logs-metrics#configure_logging_and_monitoring) for the target Distributed Cloud project. 2. [Create the target Distributed Cloud cluster](https://docs.cloud.google.com/distributed-cloud/connected/1.5.1/docs/clusters#create). 3. [Configure your Distributed Cloud networking](https://docs.cloud.google.com/distributed-cloud/connected/1.5.1/docs/networking) so that Pods in the target Distributed Cloud cluster can reach the Google Cloud data center. 4. Bind each `local-block` persistent volume on each Distributed Cloud node that you don't want to be abstracted by Symcloud Storage. If you unbind a bound `local-block` persistent volume, then installing Symcloud Storage wipes the contents of that persistent volume. For instructions, see [Binding](https://kubernetes.io/docs/concepts/storage/persistent-volumes/#binding) in the Kubernetes documentation. ## Install Symcloud Storage on a Distributed Cloud node To install Symcloud Storage on a Distributed Cloud node, complete the following steps: 1. Use the following command to apply the Symcloud Storage license to your cluster. Replace `LICENSE_FILE` with the full path and name of the Symcloud Storage license file. ``` kubectl apply -f LICENSE_FILE -n robin-admin ``` 2. Use the following command to verify the status of the `RobinCluster` service and all the Symcloud Storage nodes: ``` kubectl describe robinclusters -n robinio ``` The command returns output similar to the following: [...] Status: [...] Phase: Ready robin_node_status: [...] Status: Ready [...] Status: Ready [...] Status: Ready [...] The expected status for the service and nodes is `Ready`. ## Set Symcloud Storage as the default storage class Use the following command to set Symcloud Storage as the default storage class on your Distributed Cloud cluster. Replace `STORAGE_CLASS` with one of the [Symcloud Storage classes](https://docs.cloud.google.com/distributed-cloud/connected/1.5.1/docs/storage#classes). ``` kubectl patch storageclass STORAGE_CLASS -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}' ``` For more information about setting the default storage class, see [Change the default StorageClass](https://kubernetes.io/docs/tasks/administer-cluster/change-default-storage-class/) in the Kubernetes documentation. ## Configure abstracted Symcloud Storage volumes for workloads This section provides examples for how to use Symcloud Storage classes to configure abstracted storage for your Distributed Cloud workloads. For more details about configuring Symcloud Storage volumes, see [Using Robin CNS in Kubernetes](https://docs.robin.io/storage/1.5.1/storage.html). ### Configure an `ext4` RWO volume in file system mode The following example illustrates how to configure a persistent volume claim for an RWO volume in file system mode with the `ext4` file system. Replace `STORAGE_CLASS` with one of the [Symcloud Storage classes](https://docs.cloud.google.com/distributed-cloud/connected/1.5.1/docs/storage#classes). ``` apiVersion: v1 kind: PersistentVolumeClaim metadata: name: rwo-fs-pvc spec: accessModes: - ReadWriteOnce resources: requests: storage: 10Gi storageClassName: STORAGE_CLASS ``` ### Configure an RWO volume in block mode The following example illustrates how to configure a persistent volume claim for an RWO volume in block mode. Replace `STORAGE_CLASS` with one of the [Symcloud Storage classes](https://docs.cloud.google.com/distributed-cloud/connected/1.5.1/docs/storage#classes). ``` apiVersion: v1 kind: PersistentVolumeClaim metadata: name: rwo-block-pvc spec: accessModes: - ReadWriteOnce resources: requests: storage: 10Gi storageClassName: STORAGE_CLASS volumeMode: Block ``` ### Modify the configuration of an existing volume The following example illustrates how to modify the configuration of an existing Symcloud Storage LZ4 compressed RWO volume by using annotations. Replace`STORAGE_CLASS` with one of the [Symcloud Storage classes](https://docs.cloud.google.com/distributed-cloud/connected/1.5.1/docs/storage#classes). ``` apiVersion: v1 kind: PersistentVolumeClaim metadata: name: compressed-rwo-fs-pvc annotations: robin.io/compression: LZ4 spec: accessModes: - ReadWriteOnce resources: requests: storage: 10Gi storageClassName: STORAGE_CLASS ``` The following example illustrates how to modify the configuration of an existing Symcloud Storage RWO volume with the `xfs` file system by using annotations. Replace`STORAGE_CLASS` with one of the [Symcloud Storage classes](https://docs.cloud.google.com/distributed-cloud/connected/1.5.1/docs/storage#classes). ``` apiVersion: v1 kind: PersistentVolumeClaim metadata: name: rwo-xfs-pvc annotations: robin.io/fstype: xfs spec: accessModes: - ReadWriteOnce resources: requests: storage: 10Gi storageClassName: STORAGE_CLASS ``` ### Configure the Symcloud Storage CLI client Symcloud Storage provides a command-line interface (CLI) client that you can use to manage your Symcloud Storage configuration. To configure the client on your Distributed Cloud cluster, complete the following steps: 1. Get the Symcloud Storage image path used by the `RobinCluster` service instance deployed on your Distributed Cloud cluster: ``` kubectl get robincluster -o jsonpath='{.items[].spec.image_robin}' ``` 2. Create a `robincli` resource with the following contents. Replace `ROBIN_CNS_IMAGE` with the full path and name of the image that you obtained in step 1. ``` kind: Deployment apiVersion: apps/v1 metadata: name: robincli namespace: default labels: name: robincli spec: replicas: 1 selector: matchLabels: name: robincli template: metadata: annotations: product: robin labels: name: robincli spec: containers: - name: robincli image: ROBIN_CNS_IMAGE workingDir: /root command: ["/bin/bash","-c","mkdir -p /root/.robin; ln -s -t /usr/lib/python3.7/site-packages/ /opt/robin/current/python3/site-packages/robincli /opt/robin/current/python3/site-packages/stormgr_def.py /opt/robin/current/python3/site-packages/stormgr_lib.py; /opt/robin/current/bin/robin client add-context robin-master.robinio --set-current; while true; do sleep 10000; done"] resources: requests: memory: "10Mi" cpu: "100m" ``` 3. Apply the `robincli` resource onto your Distributed Cloud cluster. 4. Upon initial installation, Symcloud Storage generates a `default-admin-user` secret in the `robinio` namespace with a randomized password. Use the following commands to obtain these logon credentials: 1. Obtain the user name: ``` kubectl -n robinio get secret default-admin-user -o jsonpath='{.data.username}' | base64 -d ``` 2. Obtain the password: ``` kubectl -n robinio get secret default-admin-user -o jsonpath='{.data.password}' | base64 -d ``` 5. Log on to the newly created Pod and run the client: ``` kubectl exec -it robincli -- bash ``` ## Limitations of Symcloud Storage When using Symcloud Storage with Distributed Cloud, you can only achieve high availability if your Distributed Cloud cluster consists of three or more Distributed Cloud nodes.