Snapshot and restore in Elasticsearch - Mini Project: Build & Apply

Snapshot and Restore in Elasticsearch

📖 Scenario: You are managing an Elasticsearch cluster for a small online store. You want to create a backup of your data so you can restore it later if needed.

🎯 Goal: Learn how to create a snapshot repository, take a snapshot of an index, and restore the index from the snapshot in Elasticsearch.

📋 What You'll Learn

Create a snapshot repository named my_backup of type fs with location /usr/share/elasticsearch/backup

Create a snapshot named snapshot_1 in the my_backup repository for the index products

Restore the products index from the snapshot named snapshot_1 in the my_backup repository

💡 Why This Matters

🌍 Real World

Backing up and restoring Elasticsearch data is essential for data safety and disaster recovery in real-world applications.

💼 Career

Database administrators and DevOps engineers use snapshot and restore features to maintain data integrity and availability.

1

Create Snapshot Repository

Use the Elasticsearch API to create a snapshot repository called my_backup of type fs with the location set to /usr/share/elasticsearch/backup. Write the JSON body for the PUT request to /_snapshot/my_backup.

Elasticsearch

{
  "type": "fs",
  "settings": {
    "location": "/usr/share/elasticsearch/backup"
  }
}

# Your code here

Hint

The repository type fs means filesystem. The location is the folder path where snapshots will be stored.

2

Create Snapshot

Write the JSON body for a PUT request to /_snapshot/my_backup/snapshot_1 that creates a snapshot named snapshot_1 for the index products. Include the indices field with the value products.

Elasticsearch

{
  "indices": "products"
}

# Your code here

Hint

The indices field specifies which index to include in the snapshot.

3

Restore Snapshot

Write the JSON body for a POST request to /_snapshot/my_backup/snapshot_1/_restore that restores the products index from the snapshot. Include the indices field with the value products.

Elasticsearch

{
  "indices": "products"
}

# Your code here

Hint

Restoring requires specifying which indices to restore from the snapshot.

4

Verify Snapshot and Restore Setup

Add the final step to verify the snapshot repository exists by writing a GET request to /_snapshot/my_backup. This confirms the repository is registered and ready.

Elasticsearch

# Your code here
GET /_snapshot/my_backup

Hint

Use a GET request to check the snapshot repository status.

Practice

1. What is the main purpose of taking a snapshot in Elasticsearch?

easy

A. To save a backup of your data for recovery later

B. To speed up search queries

C. To delete old indexes automatically

D. To create new indexes from templates

Solution

1. Step 1: Understand snapshot purpose

   A snapshot in Elasticsearch is used to save a backup of your data at a point in time.

2. Step 2: Compare options

   Options B, C, and D describe other Elasticsearch features, not snapshot backup.

3. Final Answer:

   To save a backup of your data for recovery later -> Option A

4. Quick Check:

   Snapshot = Backup [OK]

Hint: Snapshots save data backups for recovery [OK]

Common Mistakes:

• Confusing snapshots with index templates
• Thinking snapshots speed up searches
• Assuming snapshots delete data

2. Which of the following is the correct syntax to create a snapshot repository in Elasticsearch?

easy

A. POST /_snapshot/my_backup {"type": "fs", "settings": {"location": "/mount/backups"}}

B. PUT /_snapshot/my_backup {"type": "fs", "settings": {"location": "/mount/backups"}}

C. GET /_snapshot/my_backup {"type": "fs", "settings": {"location": "/mount/backups"}}

D. DELETE /_snapshot/my_backup {"type": "fs", "settings": {"location": "/mount/backups"}}

Solution

1. Step 1: Identify correct HTTP method for creating repository

   Creating a snapshot repository uses the PUT method to define or update it.

2. Step 2: Check other methods

   POST is for creating snapshots, GET is for retrieving info, DELETE is for removing repositories.

3. Final Answer:

   PUT /_snapshot/my_backup {"type": "fs", "settings": {"location": "/mount/backups"}} -> Option B

4. Quick Check:

   Repository creation = PUT [OK]

Hint: Use PUT to create or update snapshot repositories [OK]

Common Mistakes:

• Using POST instead of PUT for repository creation
• Confusing GET with creation commands
• Trying to delete instead of create repository

3. Given this snapshot restore request:

POST /_snapshot/my_backup/snapshot_1/_restore
{
  "indices": "index1,index2",
  "rename_pattern": "index(.*)",
  "rename_replacement": "restored_index$1"
}

What will be the name of the restored index originally named index2?

medium

A. restored_index2

B. restored_index_index2

C. index2

D. index_restored2

Solution

1. Step 1: Understand rename_pattern and rename_replacement

   The pattern "index(.*)" captures the part after "index". The replacement "restored_index$1" adds "restored_index" plus the captured part.

2. Step 2: Apply to index2

   For "index2", the captured part is "2", so the new name is "restored_index2".

3. Final Answer:

   restored_index2 -> Option A

4. Quick Check:

   Rename pattern + replacement = restored_index2 [OK]

Hint: Captured group $1 appends after renamed prefix [OK]

Common Mistakes:

• Ignoring rename_pattern and keeping original name
• Adding extra 'index' in the replacement
• Misplacing the captured group in new name

4. You try to restore a snapshot but get an error: repository_missing_exception. What is the most likely cause?

medium

A. The snapshot name is incorrect

B. The cluster is running an incompatible Elasticsearch version

C. The snapshot repository does not exist or is not registered

D. The indices in the snapshot are corrupted

Solution

1. Step 1: Understand repository_missing_exception meaning

   This error means Elasticsearch cannot find the snapshot repository to access snapshots.

2. Step 2: Check other options

   Snapshot name errors cause different exceptions; corrupted indices cause restore failures but not repository missing; version mismatch causes other errors.

3. Final Answer:

   The snapshot repository does not exist or is not registered -> Option C

4. Quick Check:

   repository_missing_exception = missing repository [OK]

Hint: Check repository registration if repository_missing_exception occurs [OK]

Common Mistakes:

• Assuming snapshot name typo causes repository_missing_exception
• Blaming corrupted indices for repository errors
• Ignoring repository setup before restore

5. You want to restore only specific indexes from a snapshot but rename them to avoid conflicts. Which JSON snippet correctly does this during restore?

{
  "indices": "logs-2023,metrics-2023",
  "rename_pattern": "(.*)-2023",
  "rename_replacement": "$1-restore"
}

hard

A. Restores only logs-restore and metrics-restore indexes from snapshot

B. Restores logs-2023 and metrics-2023 with original names

C. Restores all indexes in snapshot renamed with -restore suffix

D. Restores logs-2023 and metrics-2023 as logs-restore and metrics-restore

Solution

1. Step 1: Analyze indices and rename_pattern

   Indices "logs-2023" and "metrics-2023" match the pattern "(.*)-2023" capturing "logs" and "metrics".

2. Step 2: Apply rename_replacement

   Replacement "$1-restore" changes names to "logs-restore" and "metrics-restore".

3. Step 3: Confirm only specified indices restored

   Only indices listed in "indices" are restored, renamed as specified.

4. Final Answer:

   Restores logs-2023 and metrics-2023 as logs-restore and metrics-restore -> Option D

5. Quick Check:

   Indices filtered + renamed correctly = Restores logs-2023 and metrics-2023 as logs-restore and metrics-restore [OK]

Hint: Use indices + rename_pattern/replacement to rename on restore [OK]

Common Mistakes:

• Restoring all snapshot indices ignoring filter
• Not using rename_pattern correctly
• Expecting renamed indexes to exist before restore