Distributed Cloud Edge version 1.5.1

For version information, see the Distributed Cloud Edge release notes.

Available versions: 1.7.1 1.7.0 1.6.1 1.6.0 1.5.1

Configure Distributed Cloud Edge for Symcloud Storage

By default, workloads running on one Google Distributed Cloud Edge node cannot access the local storage of another Distributed Cloud Edge node. However, you can configure Google Distributed Cloud Edge to use Rakuten Symcloud Storage, which is a third-party solution that acts as a local storage abstraction layer on each Distributed Cloud Edge node and makes its local storage available to workloads running on other Distributed Cloud Edge 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 Edge and might engage the third-party provider for assistance. Software updates for Symcloud Storage are included in the Distributed Cloud Edge software updates.

Symcloud Storage classes

This section describe the storage classes that Symcloud Storage can enable on your Distributed Cloud Edge cluster. Symcloud Storage on Distributed Cloud Edge 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.

`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

`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

`robin-repl-3` storage class

The robin-repl-3 is an RWO storage class with three replicas that span across multiple Distributed Cloud Edge 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:

Configure logging and monitoring for the target Distributed Cloud Edge project.
Create the target Distributed Cloud Edge cluster.
Configure your Distributed Cloud Edge networking so that Pods in the target Distributed Cloud Edge cluster can reach the Google Cloud data center.
Bind each local-block persistent volume on each Distributed Cloud Edge 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 in the Kubernetes documentation.

Install Symcloud Storage on a Distributed Cloud Edge node

To install Symcloud Storage on a Distributed Cloud Edge node, complete the following steps:

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
```

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 Edge cluster. Replace STORAGE_CLASS with one of the Symcloud 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 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 Edge workloads. For more details about configuring Symcloud Storage volumes, see Using Robin CNS in Kubernetes.

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.

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.

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. ReplaceSTORAGE_CLASS with one of the Symcloud 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. ReplaceSTORAGE_CLASS with one of the Symcloud 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 Edge cluster, complete the following steps:

Get the Symcloud Storage image path used by the RobinCluster service instance deployed on your Distributed Cloud Edge cluster:
```
kubectl get robincluster -o jsonpath='{.items[].spec.image_robin}'
```

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"

Apply the robincli resource onto your Distributed Cloud Edge cluster.
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
```
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 Edge, you can only achieve high availability if your Distributed Cloud Edge cluster consists of three or more Distributed Cloud Edge nodes.