Create automated snapshots

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Create automated snapshots

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To set up automated snapshots for Elasticsearch on Kubernetes you have to:

Ensure you have the necessary Elasticsearch storage plugin installed.
Add snapshot repository credentials to the Elasticsearch keystore.
Register the snapshot repository with the Elasticsearch API.
Set up a CronJob to take snapshots on a schedule.

The examples described in the following sections use the Google Cloud Storage Repository Plugin.

Support for S3, GCS and Azure repositories is bundled in Elasticsearch by default from version 8.0.

For more information on Elasticsearch snapshots, check Snapshot and Restore.

Install the storage repository plugin

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To install the storage repository plugin, you can either use a custom image or add your own init container which installs the plugin when the Pod is created.

To use your own custom image with all necessary plugins pre-installed, use an Elasticsearch resource like the following one:

apiVersion: elasticsearch.k8s.elastic.co/v1
kind: Elasticsearch
metadata:
  name: elasticsearch-sample
spec:
  version: 8.15.3
  image: your/custom/image:tag
  nodeSets:
  - name: default
    count: 1

Alternatively, install the plugin when the Pod is created by using an init container:

apiVersion: elasticsearch.k8s.elastic.co/v1
kind: Elasticsearch
metadata:
  name: elasticsearch-sample
spec:
  version: 8.15.3
  nodeSets:
  - name: default
    count: 1
    podTemplate:
      spec:
        initContainers:
        - name: install-plugins
          command:
          - sh
          - -c
          - |
            bin/elasticsearch-plugin install --batch repository-gcs

Assuming you stored this in a file called elasticsearch.yaml you can in both cases create the Elasticsearch cluster with:

kubectl apply -f elasticsearch.yaml

Configure GCS credentials through the Elasticsearch keystore

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The Elasticsearch GCS repository plugin requires a JSON file that contains service account credentials. These need to be added as secure settings to the Elasticsearch keystore. For more details, check Google Cloud Storage Repository.

Using ECK, you can automatically inject secure settings into a cluster node by providing them through a secret in the Elasticsearch Spec.

Create a file containing the GCS credentials. For this example, name it gcs.client.default.credentials_file. The file name is important as it is reflected in the secure setting.

{
  "type": "service_account",
  "project_id": "your-project-id",
  "private_key_id": "...",
  "private_key": "-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n",
  "client_email": "service-account-for-your-repository@your-project-id.iam.gserviceaccount.com",
  "client_id": "...",
  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
  "token_uri": "https://accounts.google.com/o/oauth2/token",
  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
  "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/your-bucket@your-project-id.iam.gserviceaccount.com"
}

Create a Kubernetes secret from that file:

kubectl create secret generic gcs-credentials --from-file=gcs.client.default.credentials_file

Edit the secureSettings section of the Elasticsearch resource:

apiVersion: elasticsearch.k8s.elastic.co/v1
kind: Elasticsearch
metadata:
  name: elasticsearch-sample
spec:
  version: 8.15.3
  # Inject secure settings into Elasticsearch nodes from a k8s secret reference
  secureSettings:
  - secretName: gcs-credentials

If you haven’t followed these instructions and named your GCS credentials file differently, you can still map it to the expected name now. Check Secure Settings for details.

Apply the modifications:
```
kubectl apply -f elasticsearch.yml
```

GCS credentials are automatically propagated into each Elasticsearch node’s keystore. It can take up to a few minutes, depending on the number of secrets in the keystore. You don’t have to restart the nodes.

Register the repository in Elasticsearch

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Create the GCS snapshot repository in Elasticsearch. You can either use the Snapshot and Restore UI in Kibana version 7.4.0 or higher, or follow the procedure described in Snapshot and Restore:
```
PUT /_snapshot/my_gcs_repository
{
  "type": "gcs",
  "settings": {
    "bucket": "my_bucket",
    "client": "default"
  }
}
```
Take a snapshot with the following HTTP request:
```
PUT /_snapshot/my_gcs_repository/test-snapshot
```

Periodic snapshots with Snapshot Lifecycle Management

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You can use the snapshot lifecycle management APIs to manage policies for the time and frequency of automatic snapshots (in version 7.4.0 or higher).

The Snapshot and Restore UI allows you to manage these policies directly in Kibana.

Periodic snapshots with a CronJob

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If you are running older versions of Elasticsearch without the snapshot lifecycle management feature, you can still set up a simple CronJob to take a snapshot every day.

Make an HTTP request against the appropriate endpoint, using a daily snapshot naming format. Elasticsearch credentials are mounted as a volume into the job’s Pod:

# snapshotter.yml
apiVersion: batch/v1
kind: CronJob
metadata:
  name: elasticsearch-sample-snapshotter
spec:
  schedule: "@daily"
  concurrencyPolicy: Forbid
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - name: snapshotter
            image: centos:7
            volumeMounts:
              - name: es-basic-auth
                mountPath: /mnt/elastic/es-basic-auth
            command:
            - /bin/bash
            args:
            - -c
            - 'curl -s -i -k -u "elastic:$(</mnt/elastic/es-basic-auth/elastic)" -XPUT "https://elasticsearch-sample-es-http:9200/_snapshot/my_gcs_repository/%3Csnapshot-%7Bnow%2Fd%7D%3E" | tee /dev/stderr | grep "200 OK"'
          restartPolicy: OnFailure
          volumes:
          - name: es-basic-auth
            secret:
              secretName: elasticsearch-sample-elastic-user

Apply it to the Kubernetes cluster:
```
kubectl apply -f snapshotter.yml
```

For more details, check Kubernetes CronJobs.

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