KubeDB v2021.03.17- Introducing MariaDB and Re-designed PostgreSQL operator

We are pleased to announce KubeDB v2021.03.17 . This post lists all the major changes done in this release since v2021.01.26. This release offers MariaDB support with Galera Clustering, Backup and Recovery, TLS and many more features. It also contains the fix for the PostgreSQL data loss issue. The support for the PostgreSQL TLS configuration and the support for official TimescaleDB images has also been added to this release.

MariaDB

We are very excited to announce that MariaDB support has been added to KubeDB. It offers a number of cool features including Galera Clustering, TLS/SSL encryption, Backup, and Restore Custom Configuration and Monitoring.

• Multi-Master Support for clustering: KubeDB operator supports Galera Cluster in MariaDB which offers a virtually synchronous multi-master cluster. That means reading and writing from any cluster node is possible.
• Backup and Restore Database: MariaDB supports backup and restores using Stash. For more information, visit here .
• TLS Support: To add an extra layer of security, KubeDB can automate provisioning SSL certificates to encrypt client/server communication. This is an enterprise feature.
• Custom Configuration for MariaDB: KubeDB provides custom configuration for MariaDB databases using a configuration file or using a pod template.
• Monitoring via Prometheus: Monitoring support has been added using a built-in Prometheus scraper and Prometheus operator.
• Supported MariaDB version: MariaDB version 10.5.8 and 10.4.17 are supported in this release.

PostgreSQL

PostgreSQL operator has been updated to support official images provided by 2 distributions:

• Official PostgreSQL
• TimescaleDB

Postgres Data Loss Issue Resolved: In the new release, we have finally shifted from Kubernetes leader election to directly using raft protocol to elect new primary instance. For every pod, there will be a sidecar running along with a PostgreSQL container. This sidecar will make sure that among all active pods, the pod with the highest WAL position will be the leader or primary. And other replicas will try to sync with the primary. This addresses a long standing issue where a flaky connection to the Kubernetes control plane will result in loss of leader and trigger a sequence of events that might eventually lead to data loss. In this release, we have avoided the scenario where replicas have always taken base backup from the master whenever a failover happens. In case of failover, the redesigned operator will make sure that the current master is in the Ready status if replicas need to take base backup.

Updated leaderElection field:

leaderElection:
    # 10*period = 10*100ms = 1000ms
    electionTick: 10 
    # 1*period = 1*100ms = 100ms
    heartbeatTick: 1 
    period: 100ms 
   # 33554432 = 32MB if the replica is lagging from master more than 32MB in wal position, replica is going to take base backup from master.
   maximumLagBeforeFailover: 33554432  

• Support for latest versions: KubeDB now supports PostgreSQL version 13.2, 12.6, 11.11, 10.16, and 9.6.21.
• TLS support for PostgreSQL cluster: In this release, we have added support for encrypting client/server communications for increased security.
• Client authentication mode: We have introduced SCRAM-SHA-256 authentication support to verify the user’s password and client certificate authentication method when a PostgreSQL cluster has enabled SSL.
• Wal-g support has been dropped: We have dropped continuous archiving with wal-g for now. We are planning to bring back this feature via Stash (the backup solution) in the future.

MySQL

• Introduce new MySQL versions: 8.0.23 and 5.7.33.
• Various improvements made to the on-start script in MySQL docker image for fixing restart problems.
• Introduce clone plugin from version 8.0.20-v1 to 8.0.23 for new joiner(MySQL instance) into a group replicated cluster. The clone plugin permits cloning data from other MySQL server instances at the time of joining a group. This process will be automatically triggered when the joiner gets a valid donor and the primary member’s data will be greater than or equal to 128MB.
• By default set various environment variables for fixing memory leak issues and getting better performance. These settings are recommended and users can overwrite these by passing environment variables or using the pod template args. Recommended default settings are:
  • Reserved 256MB memory for performance schema and other processes.
  • Then allocate 75% of the available memory for InnoDB buffer pool size.
  • Then allocate the rest of the memory for group replication cache size.
• Improve MySQL docs: QuickStart, Concept, Clustering, Upgrading, Scaling, TLS configuration, etc.
• MySQLOpsRequest spec is now immutable i.e. the spec can’t be changed once the Ops Request has been created.
• Only One MySQLOpsRequest can be in the Progressing phase at a time.
• Added validation and mutation webhook for MySQLOpsRequest.
• Added support for using different cert-manager Issuer/ClusterIssuer for different certificates.

MongoDB

• MongoDBOpsRequest spec is now immutable i.e. the spec can’t be changed once the Ops Request has been created.
• Only One MongoDBOpsRequest can be in the Progressing phase at a time.
• Added validation webhook for MongoDBOpsRequest.
• Added support for using different cert-manager Issuer/ClusterIssuer for different certificates. This is necessary to use HashiCorp Vault to provision TLS certificates.
• Added IPv6 support in MongoDB.
• Improved various MongoDB and MongoDBOpsRequest docs.

Elasticsearch

• Replaced busybox images with toybox/alpine images for the init-containers.
• Added support for new Elasticsearch versions: searchguard-7.3.2, searchguard-7.9.3, opendistro-1.10.1, opendistro-1.11.0, opendistro-1.12.0.
• User provided custom config files are mounted on the "$ES_CONFIG_DIR/custom-config/" node directory.
• Update ENV while upgrading Elasticsearch version from V6 to V7: like discovery.zen.minimum_master_nodes will become cluster.initial_master_nodes.
• Introduce a new ElasticsearchVersion naming convention: {Distribution Name}-{Application Version}-{Modification Tag}. Samples: xpack-7.9.1-v1, searchguard-7.9.3, opendistro-1.12.0, etc.
• Allow users to provide custom passwords for the default internal database users like kibanaserver, readall, etc.
• Improve Elasticsearch docs: Quickstart, Concepts, Clustering, Custom Configuration, Auto Scaling.
• Added support for IPv6 in Elasticsearch.
• ElasticsearchOpsRequest spec is now immutable i.e. the spec can’t be changed once the Ops Request has been created.
• Only One ElasticsearchOpsRequest can be in the Progressing phase at a time.
• Added validation webhook for ElasticsearchOpsRequest.
• Added support for using different cert-manager Issuer/ClusterIssuer for different certificates.

Redis

• Added TLS reconfigure, Restart OpsRequests support for Redis.
• RedisOpsRequest spec is now immutable i.e. the spec can’t be changed once the Ops Request has been created.
• Only One RedisOpsRequest can be in the Progressing phase at a time.
• Added validation webhook for RedisOpsRequest.
• Added support for using different cert-manager Issuer/ClusterIssuer for different certificates.

What Next?

Please try the latest release and give us your valuable feedback.

• If you want to install KubeDB, please follow the installation instruction from here .
• If you want to upgrade KubeDB from a previous version, please follow the upgrade instruction from here .

Support

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If you have found a bug with KubeDB or want to request for new features, please file an issue .

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