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Version: 3.1

snaps-annotations

This document will show you how to take a snapshot of a volume using Portworx and use that snapshot as the volume for a new pod.

Taking periodic snapshots on a running POD​

When you create the Storage Class, you can specify a snapshot schedule on the volume as specified below:

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: portworx-io-priority-high
provisioner: pxd.portworx.com
parameters:
  repl: "1"
  snap_interval:   "24"
  io_priority:  "high"

Creating a snapshot on demand​

You can trigger a new snapshot on a running POD by creating a PersistentVolumeClaim.

Using annotations​

Portworx uses a special annotation px/snapshot-source-pvc which can be used to identify the name of the source PVC whose snapshot needs to be taken.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  namespace: prod
  name: ns.prod-name.px-snap-1
  annotations:
    volume.beta.kubernetes.io/storage-class: px-sc
    px/snapshot-source-pvc: px-vol-1
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 6Gi

Note the format of the name field - ns.<namespace_of_source_pvc>-name.<name_of_the_snapshot>. The above example takes a snapshot with the name px-snap-1 of the source PVC px-vol-1 in the prod namespace.

You can run the following command to edit your existing Portworx ClusterRole

Clone from a snapshot​

You can restore a clone from a snapshot using the following spec file. In 1.3 and higher releases, this is required to create a read-write clone as snapshots are read only.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  namespace: prod
  name: ns.prod-name.px-snap-restore
  annotations:
    volume.beta.kubernetes.io/storage-class: px-sc
    px/snapshot-source-pvc: ns.prod-name.px-snap-1
spec:
   accessModes:
     - ReadWriteOnce
   resources:
     requests:
       storage: 2Gi

The above example restores a volume from the source snapshot PVC with name ns.prod-name.px-snap-1.

Using inline spec​

If you do not wish to use annotations you can take a snapshot by providing the source PVC name in the name field of the claim. However this method does not allow you to provide namespaces.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: name.snap001-source.pvc001
  annotations:
    volume.beta.kubernetes.io/storage-class: px-sc
spec:
  accessModes:
     - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

Note the format of the “name” field. The format is name.<new_snap_name>-source.<old_volume_name>. Above example references the parent (source) persistent volume claim pvc001 and creates a snapshot by the name snap001.

Clone from a snapshot​

You can restore a clone from a snapshot using the following spec file. In 1.3 and higher releases, this is required to create a read-write clone as snapshots are read only.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: name.rollback001-source.snap001
  annotations:
    volume.beta.kubernetes.io/storage-class: px-sc
spec:
  accessModes:
     - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

Note we used used the existing snapshot name in the source part of the inline spec.

Using snapshots​

Listing snapshots​

To list your snapshots, use the pxctl volume list --snapshot command as follows:

pxctl volume list --snapshot
ID			NAME	SIZE	HA	SHARED	IO_PRIORITY	SCALE STATUS
1067822219288009613	snap001	1 GiB	2	no	LOW		1	up - detached

You can use the ID or NAME of the snapshots when using them to restore a volume.

Restoring a pod from a snapshot​

To restore a pod to use the created snapshot, use the pvc name.snap001-source.pvc001 in the pod spec.

Managing snapshots through pxctl​

To demonstrate the capabilities of the SAN like functionality offered by Portworx, try creating a snapshot of your mysql volume.

First create a database and a demo table in your mysql container.

mysql --user=root --password=password
create database pxdemo;
Query OK, 1 row affected (0.00 sec)
use pxdemo;
Database changed
create table grapevine (counter int unsigned);
Query OK, 0 rows affected (0.04 sec)
quit;
Bye

Create a snapshot of this database using pxctl​

First use pxctl volume list to see what volume you want to snapshot

bin/pxctl volume list
ID					NAME										SIZE	HA	SHARED	ENCRYPTED	IO_PRIORITY	SCALE	STATUS
381983511213673988	pvc-xxxxxxxx-xxxx-xxxx-xxxx-7cd30ac1a138	20 GiB	2	no		no			LOW			0		up - attached on xx.xx.105.241

Then use pxctl to snapshot your volume

pxctl volume snapshot 381983511213673988 --name snap-01
Volume successfully snapped: 835956864616765999

You can use pxctl to see your snapshot

pxctl snap list
ID					NAME	SIZE	HA	SHARED	ENCRYPTED	IO_PRIORITY	SCALE	STATUS
835956864616765999	snap-01	20 GiB	2	no		no			LOW			0		up - detached

Now you can create a mysql Pod to mount the snapshot

Download example

apiVersion: v1
kind: Pod
metadata:
  name: test-portworx-snapped-volume-pod
spec:
  containers:
  - image: mysql:5.6
    name: mysql-snap
    env:
      # Use secret in real usage
    - name: MYSQL_ROOT_PASSWORD
      value: password
    ports:
    - containerPort: 3306
      name: mysql
    volumeMounts:
    - name: snap-01
      mountPath: /var/lib/mysql
  volumes:
  - name: snap-01
    # This Portworx volume must already exist.
    portworxVolume:
      volumeID: "vol1"

Inspect that the database shows the cloned tables in the new mysql instance.

mysql --user=root --password=password
show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| pxdemo             |
+--------------------+
4 rows in set (0.00 sec)

use pxdemo;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
show tables;
+------------------+
| Tables_in_pxdemo |
+------------------+
| grapevine        |
+------------------+
1 row in set (0.00 sec)
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