Skip to content

Container Object Storage Interface (COSI)

The Ceph COSI driver provisions buckets for object storage. This document instructs on enabling the driver and consuming a bucket from a sample application.

Note

The Ceph COSI driver is currently in experimental mode.

Prerequisites

COSI requires:

  1. A running Rook object store
  2. COSI controller

Deploy the COSI controller with these commands:

1
2
kubectl apply -k github.com/kubernetes-sigs/container-object-storage-interface-api
kubectl apply -k github.com/kubernetes-sigs/container-object-storage-interface-controller

Ceph COSI Driver

The Ceph COSI driver will be started when the CephCOSIDriver CR is created and when the first CephObjectStore is created.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
apiVersion: ceph.rook.io/v1
kind: CephCOSIDriver
metadata:
  name: ceph-cosi-driver
  namespace: rook-ceph
spec:
  deploymentStrategy: "Auto"
---
# The Ceph-COSI driver needs a privileged user for each CephObjectStore
# in order to provision buckets and users
apiVersion: ceph.rook.io/v1
kind: CephObjectStoreUser
metadata:
  name: cosi
  namespace: rook-ceph # rook operator namespace
spec:
  displayName: "cosi user"
  store: my-store # name of the CephObjectStore
  capabilities:
    bucket: "*"
    user: "*"

1
2
cd deploy/examples/cosi
kubectl create -f cephcosidriver.yaml

Admin Operations

Create a BucketClass and BucketAccessClass

The BucketClass and BucketAccessClass are CRDs defined by COSI. The BucketClass defines the storage class for the bucket. The BucketAccessClass defines the access class for the bucket. The BucketClass and BucketAccessClass are defined as below:

1
2
3
4
5
6
7
8
9
kind: BucketClass
apiVersion: objectstorage.k8s.io/v1alpha1
metadata:
  name: sample-bcc
driverName: rook-ceph.ceph.objectstorage.k8s.io
deletionPolicy: Delete
parameters:
  objectStoreUserSecretName: rook-ceph-object-user-my-store-cosi
  objectStoreUserSecretNamespace: rook-ceph

1
2
3
4
5
6
7
8
9
kind: BucketAccessClass
apiVersion: objectstorage.k8s.io/v1alpha1
metadata:
  name: sample-bac
driverName: rook-ceph.ceph.objectstorage.k8s.io
authenticationType: KEY
parameters:
  objectStoreUserSecretName: rook-ceph-object-user-my-store-cosi
  objectStoreUserSecretNamespace: rook-ceph

1
kubectl create -f bucketclass.yaml -f bucketaccessclass.yaml

The objectStoreUserSecretName and objectStoreUserSecretNamespace are the name and namespace of the CephObjectStoreUser created in the previous step.

User Operations

Create a Bucket

To create a bucket, use the BucketClass to pointing the required object store and then define BucketClaim request as below:

1
2
3
4
5
6
7
8
9
kind: BucketClaim
apiVersion: objectstorage.k8s.io/v1alpha1
metadata:
  name: sample-bc
  namespace: default # any namespace can be used
spec:
  bucketClassName: sample-bcc
  protocols:
    - s3

1
kubectl create -f bucketclaim.yaml

Bucket Access

Define access to the bucket by creating the BucketAccess resource:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
kind: BucketAccess
apiVersion: objectstorage.k8s.io/v1alpha1
metadata:
  name: sample-access
  namespace: default # any namespace can be used
spec:
  bucketAccessClassName: sample-bac
  bucketClaimName: sample-bc
  protocol: s3
  # Change to the name of the secret where access details are stored
  credentialsSecretName: sample-secret-name

1
kubectl create -f bucketaccess.yaml

The secret will be created which contains the access details for the bucket in JSON format in the namespace of BucketAccess:

1
kubectl get secret sample-secret-name -o jsonpath='{.data.BucketInfo}' | base64 -d

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
{
  "metadata": {
    "name": "bc-81733d1a-ac7a-4759-96f3-fbcc07c0cee9",
    "creationTimestamp": null
  },
  "spec": {
    "bucketName": "sample-bcc1fc94b04-6011-45e0-a3d8-b6a093055783",
    "authenticationType": "KEY",
    "secretS3": {
      "endpoint": "http://rook-ceph-rgw-my-store.rook-ceph.svc:80",
      "region": "us-east",
      "accessKeyID": "LI2LES8QMR9GB5SZLB02",
      "accessSecretKey": "s0WAmcn8N1eIBgNV0mjCwZWQmJiCF4B0SAzbhYCL"
    },
    "secretAzure": null,
    "protocols": [
      "s3"
    ]
  }
}

Consuming the Bucket via secret

To access the bucket from an application pod, mount the secret for accessing the bucket:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
  volumes:
  - name: cosi-secrets
    secret:
      #  Set the name of the secret from the BucketAccess
      secretName: sample-secret-name
  spec:
    containers:
    - name: sample-app
      volumeMounts:
      - name: cosi-secrets
        mountPath: /data/cosi

The Secret will be mounted in the pod in the path: /data/cosi/BucketInfo. The app must parse the JSON object to load the bucket connection details.