Kubernetes

Configuring Snapshots on Kubernetes

This content is associated with a legacy version of the Replicated product. For the current Replicated product documentation, see docs.replicated.com.

Kubernetes Snapshots can be used to configure incremental backups for any Kubernetes resources that use a Persistent Volume Claim (PVC) for persistent storage. If your application has a Rook shared filesystem enabled any paths on the filesystem can be included in the snapshot.

Configuration

In addition to storing your application data in a PVC, you’ll need to enable it in your Replicated application yaml’s backup section. For example, to back up a PVC named redis-data-volume, use the following backup config.

backup:
  enabled: true
  kubernetes:
    pvc_names: [ "redis-data-volume" ]

Paths in the shared filesystem must also be listed. To backup the entire shared filesystem, use the root path.

backup:
  enabled: true
  kubernetes:
    shared_fs_paths: [ "/" ]

Multi-strategy snapshots can also be used with Kubernetes.

When configuring multi-strategy snapshots, all PVCs and shared filesystem paths should be included under the same strategy.

...
backup:
  enabled: true
  strategies:
    - name: full
      kubernetes:
        pvc_names: [ "redis-data-volume" ]
        shared_fs: [ "/dump" ]
...

StatefulSets

All PersistentVolumeClaims generated from a StatefulSet’s volumeClaimTemplates will be included in a snapshot if the name in the volumeClaimTemplate matches a name in the backup list of PVCs.

For example, with the following yaml two PersistentVolumeClaims would be generated: www-web-0 and www-web-1. Both would be included in your snapshots because both include www.

backup:
  enabled: true
  kubernetes: pvc_names: ["www"]

---
#kind: scheduler-kubernetes
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  selector:
    matchLabels:
      app: nginx
  serviceName: nginx
  replicas: 2
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: k8s.gcr.io/nginx-slim:0.8
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi

Example

Below is an End-to-end application config for a PVC-backed redis deployment.

---
# kind: replicated
replicated_api_version: 2.11.0
name: Redis-K8s

backup:
  enabled: true
  kubernetes:
    pvc_names: [ "redis-data-volume" ]

host_requirements:
  replicated_version: ">=2.11.0"
properties:
  logo_url: https://redis.io/images/redis-white.png
  console_title: Persistent Redis Example

---
# kind: scheduler-kubernetes
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: redis-data-volume
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi
  annotations:
    volume.beta.kubernetes.io/storage-class: standard
---
#kind: scheduler-kubernetes
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: redis
spec:
  replicas: 1
  template:
    spec:
      containers:
        - name: redis
          image: redis:3.0
          command:
            - redis-server
            - --appendonly
            - "yes"
          volumeMounts:
            - name: redis-data
              mountPath: /data
          ports:
            - containerPort: 6379
      volumes:
        - name: data
          persistentVolumeClaim:
            claimName: redis-data-volume

Configuring Snapshot Storage

When installing Replicated, application backup archives will be stored on the replicated primary’s PVC by default (local mode). This is not recommended for production deployments, and end users of replicated are encouraged to customize the backup implementation in the Replicated Admin Console under “Console Settings”. Options include using either SFTP or Amazon S3 for snapshot storage.

See the Snapshots documentation for more information on configuring snapshot storage.

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