Kubernetes Deployment Tool for OpenMLDB Online Engine

Requirement

This deployment tool offers a Kubernetes-based deployment solution for the OpenMLDB online engine, implemented using Helm Charts. The tool has been tested and verified with the following versions:

• Kubernetes 1.19+
• Helm 3.2.0+

Additionally, for users who utilize pre-compiled OpenMLDB images from Docker Hub, only OpenMLDB versions >= 0.8.2 are supported. Users also have the option to create other versions of OpenMLDB images using our tools.

Preparation: Deploy ZooKeeper

If there is an available ZooKeeper instance, you can skip this step. Otherwise, proceed with the installation process:

helm install zookeeper oci://registry-1.docker.io/bitnamicharts/zookeeper --set persistence.enabled=false

You can specify a previously created storage class for persistent storage:

helm install zookeeper oci://registry-1.docker.io/bitnamicharts/zookeeper --set persistence.storageClass=local-storage

For more parameter settings, refer to here

OpenMLDB Deployment

Download Source Code

Download the source code and set the working directory to the root directory of the repository.

git clone https://github.com/4paradigm/openmldb-k8s.git
cd openmldb-k8s

Configure ZooKeeper Address

Modify the zk_cluster in the charts/openmldb/conf/tablet.flags and charts/openmldb/conf/nameserver.flags files to the actual ZooKeeper address, with the default zk_root_path set to /openmldb.

Deploy OpenMLDB

You can achieve one-click deployment using Helm with the following commands:

helm install openmldb ./charts/openmldb

Users have the flexibility to configure additional deployment options using the --set command. Detailed information about supported options can be found in the OpenMLDB Chart Configuration.

Important configuration considerations include:

• By default, temporary files are used for data storage, which means that data may be lost if the pod restarts. It is recommended to associate a Persistent Volume Claim (PVC) with a specific storage class using the following method:

helm install openmldb ./charts/openmldb --set persistence.dataDir.enabled=true --set  persistence.dataDir.storageClass=local-storage

• By default, the 4pdosc/openmldb-online image from Docker Hub is utilized (supporting OpenMLDB >= 0.8.2). If you prefer to use a custom image, you can specify the image name during installation with --set image.openmldbImage. For information on creating custom images, refer to the image production guidelines here.

helm install openmldb ./charts/openmldb --set image.openmldbImage=openmldb-online:0.8.5

Note

• Deployed OpenMLDB services can only be accessed within the same namespace within Kubernetes.
• The OpenMLDB cluster deployed using this method does not include a TaskManager module. Consequently, statements such as LOAD DATA and SELECT INTO, and offline-related functions are not supported. If you need to import data into OpenMLDB, you can use OpenMLDB's Online Import Tool, OpenMLDB Connector, or SDK. For exporting table data, the Online Data Export Tool can be utilized.
• For production, it's necessary to disable Transparent Huge Pages (THP) on the physical node where Kubernetes deploys the tablet. Failure to do so may result in issues where deleted tables cannot be fully released. For instructions on disabling THP, please refer to this link.