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Continuous Archiving to Swift

WAL-G is used to continuously archive PostgreSQL WAL files. Please refer to continuous archiving in KubeDB to learn more about it.

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using minikube.

Now, install KubeDB cli on your workstation and KubeDB operator in your cluster following the steps here.

Note: YAML files used in this tutorial are stored in docs/examples/postgres folder in GitHub repository kubedb/docs.

To keep things isolated, this tutorial uses a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

Create PostgreSQL with Continuous Archiving

For archiving, we need storage Secret, and storage backend information. Below is a Postgres object created with Continuous Archiving support to backup WAL files to Swift Storage.

apiVersion: kubedb.com/v1alpha1
kind: Postgres
metadata:
  name: wal-postgres
  namespace: demo
spec:
  version: "11.1-v2"
  replicas: 2
  storage:
    storageClassName: "standard"
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: 50Mi
  archiver:
    storage:
      storageSecretName: swift-secret
      swift:
        container: kubedb

Here,

  • spec.archiver.storage specifies storage information that will be used by WAL-G
    • storage.storageSecretName points to the Secret containing the credentials for cloud storage destination.
    • storage.swift points to Swift storage configuration.
    • storage.swift.container points to the bucket name used to store continuous archiving data.

Archiver Storage Secret

Storage Secret should contain credentials that will be used to access storage destination.

Storage Secret for WAL-G is needed with the full set of v1, v2 or v3 authentication keys from the following list:

KeyDescription
ST_AUTHFor keystone v1 authentication
ST_USERFor keystone v1 authentication
ST_KEYFor keystone v1 authentication
OS_AUTH_URLFor keystone v2 authentication
OS_REGION_NAMEFor keystone v2 authentication
OS_USERNAMEFor keystone v2 authentication
OS_PASSWORDFor keystone v2 authentication
OS_TENANT_IDFor keystone v2 authentication
OS_TENANT_NAMEFor keystone v2 authentication
OS_AUTH_URLFor keystone v3 authentication
OS_REGION_NAMEFor keystone v3 authentication
OS_USERNAMEFor keystone v3 authentication
OS_PASSWORDFor keystone v3 authentication
OS_USER_DOMAIN_NAMEFor keystone v3 authentication
OS_PROJECT_NAMEFor keystone v3 authentication
OS_PROJECT_DOMAIN_NAMEFor keystone v3 authentication
OS_STORAGE_URLFor authentication based on tokens
OS_AUTH_TOKENFor authentication based on tokens
$ echo -n '<your-auth-url>' > OS_AUTH_URL
$ echo -n '<your-tenant-id>' > OS_TENANT_ID
$ echo -n '<your-tenant-name>' > OS_TENANT_NAME
$ echo -n '<your-username>' > OS_USERNAME
$ echo -n '<your-password>' > OS_PASSWORD
$ echo -n '<your-region>' > OS_REGION_NAME
$ kubectl create secret generic swift-secret \
    --from-file=./OS_AUTH_URL \
    --from-file=./OS_TENANT_ID \
    --from-file=./OS_TENANT_NAME \
    --from-file=./OS_USERNAME \
    --from-file=./OS_PASSWORD \
    --from-file=./OS_REGION_NAME
secret "swift-secret" created
$ kubectl get secret swift-secret -o yaml
apiVersion: v1
data:
  OS_AUTH_URL: PHlvdXItYXV0aC11cmw+
  OS_PASSWORD: PHlvdXItcGFzc3dvcmQ+
  OS_REGION_NAME: PHlvdXItcmVnaW9uPg==
  OS_TENANT_ID: PHlvdXItdGVuYW50LWlkPg==
  OS_TENANT_NAME: PHlvdXItdGVuYW50LW5hbWU+
  OS_USERNAME: PHlvdXItdXNlcm5hbWU+
kind: Secret
metadata:
  creationTimestamp: 2017-07-03T19:17:39Z
  name: swift-secret
  namespace: default
  resourceVersion: "36381"
  selfLink: /api/v1/namespaces/default/secrets/swift-secret
  uid: 47b4bcab-6024-11e7-879a-080027726d6b
type: Opaqu

Archiver Storage Backend

To configure Swift backend, following parameters are available:

ParameterDescription
spec.archiver.storage.swift.containerRequired. Name of Storage container
spec.archiver.storage.swift.prefixOptional. Path prefix into container where snapshot will be stored

Now create this Postgres object with continuous archiving support.

$ kubectl create -f https://github.com/kubedb/docs/raw/v0.13.0-rc.0/docs/examples/postgres/snapshot/wal-postgres-swift.yaml
postgres.kubedb.com/wal-postgres created

When database is ready, WAL-G takes a base backup and uploads it to the cloud storage defined by storage backend.

Archived data is stored in a folder called {container}/{prefix}/kubedb/{namespace}/{postgres-name}/archive/.

You can see continuous archiving data stored in swift container.

continuous-archiving

From the above image, you can see that the archived data is stored in a folder kubedb/kubedb/demo/wal-postgres/archive.

Termination Policy

If termination policy of this wal-postgres is set to WipeOut or, If Spec.WipeOut of dormant database is set to true, then the data in cloud backend will be deleted.

The data will be intact in other scenarios.

Cleaning up

To cleanup the Kubernetes resources created by this tutorial, run:

kubectl patch -n demo pg/wal-postgres -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"
kubectl delete -n demo pg/wal-postgres

kubectl delete -n demo secret/swift-secret
kubectl delete ns demo

Next Steps