Elasticsearch has made a lot of improvements and new features between different versions, from 5.3 to 6.8 to 7.10, each version has its own significant changes and upgrade points. Here are some of the main differences:
From 5.3 to (take 6.8 as an example)
Main architecture changes
- Breaking Changes: A large number of destructive changes were introduced, such as removing backward compatibility for older versions, which requires users to update their index mapping and query syntax when upgrading.
- Versioning: Introduced stricter version control and stricter version control of documents to solve concurrency problems.
- SQL-like DSL: Elasticsearch has begun to support the SQL-like query language, making it easier for non-professional users to execute complex queries.
New features and improvements
- Mapping Types Removal: In 6.0, the concept of mapping types was removed and the index structure was simplified. All documents now belong to the same type by default.
- Ingest Node: Logstash's function is partially integrated into Elasticsearch, and data is processed through Ingest Node, making data preprocessing more flexible.
- Graph Plugin: The version introduces the graph database plug-in to analyze the relationship between documents.
- Machine Learning Improvements: Enhanced machine learning functions, including improvements in anomaly detection and prediction capabilities.
- Security Enhancements: The X-Pack Security module was introduced to enhance the security of the cluster, including authentication, authorization and encrypted communication.
From 6.8 to (taking 7.10 as an example)
Main architecture changes
- Elastic Stack Components Integration: The series further integrates Elastic Stack components, including closer integration between Elasticsearch, Kibana, Logstash and Beats.
- Deprecation of Legacy Features: Continue to remove some legacy features, such as support for some outdated APIs.
New features and improvements
- Rollup Aggregations: Rollup Aggregations was introduced, allowing users to aggregate large amounts of data, reduce storage requirements and improve query efficiency.
- Transforms: Transforms was introduced, which can continuously convert and load data into Elasticsearch for easy real-time analysis.
- Query DSL Changes: The query DSL has been adjusted, for example, the DisMax Query and Simple Query String Query are removed to reduce the complexity of the query language.
- Filebeat Improvements: Filebeat in the Beats framework is optimized for data collection, improving stability and performance.
- Security Enhancements: Security has been further strengthened, including improved permission model and authentication mechanism.
- ML Enhancements: Machine learning capabilities continue to be enhanced, including a new data frame analysis API, making it easier to perform data analysis inside Elasticsearch.
Specific differences between each version may also involve performance optimization, bug fixes, addition of new features, and API changes. When upgrading, be sure to read the official release instructions and migration guide carefully to ensure a smooth transition.
Upgrade from Elasticsearch 5.3 to 7.10
Upgrading from Elasticsearch 5.3 to 7.10 is a process involving multiple steps. It is important to note that due to the numerous architectural changes made by Elasticsearch after 6.0, including removing types (Types), introducing stricter versioning, and many other disruptive changes, direct upgrades may be challenging. Here is a detailed upgrade plan, including the preparation phase, the actual upgrade process, and the strategies for index reconstruction and data migration:
Preparation phase
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Backup data：
- Use Snapshots to back up data from an existing cluster. Make sure your snapshot strategy is reliable and tested for recovery processes.
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Evaluate the current cluster status：
- Check the health status of the cluster and solve any existing problems.
- Analyze current index mapping, data distribution, and hardware configuration.
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Read the document：
- Read Elasticsearch and migration guide in detail to understand disruptive changes.
- Pay special attention to changes related to the features you are currently using.
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Test environment：
- Simulate the upgrade in the test environment and verify that all applications and queries are still working properly.
Upgrade process
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Phase upgrade：
- Since it may not be feasible to upgrade directly from 5.3 to 7.10, it is recommended to upgrade to 6.8 first and then from 6.8 to 7.10.
- Follow the officially recommended upgrade path and proceed step by step.
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Upgrade Elasticsearch nodes：
- First upgrade a node, observe the cluster status, and ensure there are no problems before upgrading the next node.
- Use rolling upgrades to avoid downtime.
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Update index maps and queries：
- Update index mapping and query syntax according to changes to the sum.
- Pay special attention to removing types (Types) and if multiple types are used, the index design needs to be refactored.
Index reconstruction and data migration
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Evaluate index design：
- Reevaluate the index design before upgrading, considering new features and best practices.
- You may need to adjust the number of shards, number of replicas, analyzer settings, etc.
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Rebuild the index：
- If possible, create a new index instead of directly modifying the old index.
- Use tools like Reindex API or logstash to migrate data to a new index.
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Data migration：
- Migrate data using Reindex API or logstash's input and output plugins.
- Test the migration process to ensure data integrity and correctness.
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Verify new index：
- Run queries and aggregation tests to ensure that the new index meets business needs.
- Monitor performance indicators and check whether there are any performance degradation.
Next steps
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Clean old indexes：
- After confirming that the new index is running correctly, you can delete the old index.
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Update client code：
- Update all applications that interact with Elasticsearch, making sure to use the new version of the client library.
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Monitoring and maintenance：
- Continuously monitor the cluster status after the upgrade to ensure that everything is running normally.
- Adjust cluster configuration and optimize performance.
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Training and documentation updates：
- Training on new features and changes to team members.
- Update internal documents to reflect the new architecture and operational processes.
The entire upgrade process requires careful planning and execution to ensure that the impact on the production environment is minimized. Full testing must be carried out at each stage to ensure that the upgraded system is stable and reliable.