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Table Of Contents

  1. Docs
  2. Installation & Configuration
  3. High Availability
  4. High Availability Configuration & Management

High Availability Configuration & Management

Pre-requisites

An HA installation requires two components:

  1. Two or more clusters with matching Kinetica installations registered with KAgent

    Note

    If KAgent is not installed, consult Upgrading Kinetica (No KAgent - On Premise) for more information.

  2. Two nodes (across the clusters) have RabbitMQ installed

  3. The KAgent UI

Configuration

  1. Log into the KAgent service with a web browser:

    http://<kagent-host>:8081

  2. On the Clusters page, click Rings.

  3. On the Rings page, next to the ring containing your clusters, click Enable HA.

  4. Select a mode:

  5. Click Enable. The High Availability package will be installed on each cluster and automatically configured.

  6. Click Close. The current HA mode will be listed on the Rings page.

    ../_images/ha_configured.png

    Tip

    Click Enable HA at any point to change the HA mode; the database will automatically be reconfigured after enabling a different mode.

APIs

Any client API connection made to an HA cluster ring should be configured to fail over from one cluster to another. For more information on the HA failover modes, consult Failover Modes. The enabled failover mode (active/active or active/passive) is governed by whether a primary URL is specified or implied as follows:

  • Active/Active - No primary URL is specified and more than one URL is specified
  • Active/Passive - A primary URL is specified or a single URL is specified

Important

The database will auto-discover clusters in HA rings associated with the provided URL(s) and append each cluster's head node URL to the list of URLs available for failover.

C++

Active/Active Configuration

To instantiate a Kinetica connection object with failover in C++, pass a comma-delimited list of head node URLs to the constructor:

gpudb::GPUdb gpudb("http://172.1.2.3:9191,http://172.1.2.4:9191,http://172.1.2.5:9191");

In this case, a cluster will be chosen randomly from the given list for the initial connection. Subsequent requests through the instantiated connection object will go to the same cluster.

Important

If you provide a single URL to the gpudb class object, the failover mode will instead be Active/Passive and the URL will be treated as the primary URL.

Active/Passive Configuration

To designate a cluster from the list to always attempt to go to first, specify a primary URL:

gpudb::GPUdb::Options options = gpudb::GPUdb::Options().setPrimaryUrl("http://172.1.2.4:9191");
gpudb::GPUdb gpudb("http://172.1.2.3:9191,http://172.1.2.4:9191,http://172.1.2.5:9191", options);

In either case, if the current cluster has a failure, the connector will randomly choose a failover cluster from the list to send further requests. If no operational clusters are found, an error will be returned.

Java

Active/Active Configuration

To instantiate a Kinetica connection object with failover in Java, pass a comma-delimited list of head node URLs to the constructor:

GPUdb gpudb = new GPUdb("http://172.1.2.3:9191,http://172.1.2.4:9191,http://172.1.2.5:9191");

In this case, a cluster will be chosen randomly from the given list for the initial connection. Subsequent requests through the instantiated connection object will go to the same cluster.

Important

If you provide a single URL to the gpudb class object, the failover mode will instead be Active/Passive and the URL will be treated as the primary URL.

Active/Passive Configuration

To designate a cluster from the list to always attempt to go to first, specify a primary URL:

GPUdb.Options options = new GPUdb.Options().setPrimaryUrl("http://172.1.2.4:9191");
GPUdb gpudb = new GPUdb("http://172.1.2.3:9191,http://172.1.2.4:9191,http://172.1.2.5:9191", options);

In either case, if the current cluster has a failure, the connector will randomly choose a failover cluster from the list to send further requests. If no operational clusters are found, an error will be returned.

Python

Active/Active Configuration

To instantiate a Kinetica connection object with failover in Python, pass a comma-delimited list of head node URLs to the constructor:

kinetica = gpudb.GPUdb(host=['http://172.1.2.3:9191','http://172.1.2.4:9191','http://172.1.2.5:9191'])

In this case, a cluster will be chosen randomly from the given list for the initial connection. Subsequent requests through the instantiated connection object will go to the same cluster.

Active/Passive Configuration

To designate a cluster from the list to always attempt to go to first, specify a primary host:

kinetica = gpudb.GPUdb(host=['http://172.1.2.3:9191','http://172.1.2.4:9191','http://172.1.2.5:9191'], primary_host='http://172.1.2.3:9191')

In either case, if the current cluster has a failure, the connector will randomly choose a failover cluster from the list to send further requests. If no operational clusters are found, an error will be returned.

Connectors

Any Kinetica connectors used to interface with an HA cluster ring should also be configured to fail over from one cluster to another.

ODBC

See Failover Connections for the ODBC/JDBC failover configuration.

Management

Once HA has been configured, several commands are available to aid in the management of the cluster. Run the following service with one of the commands from the table below:

service gpudb-ha <command>
Command Description
all-start Starts the gpudb, gpudb-ha, and gpudb-mq services.
all-status Displays the status of the gpudb, gpudb-ha, and gpudb-mq services.
all-stop Stops the gpudb, gpudb-ha, and gpudb-mq services.
backup-restart Restarts the backup processor service.
backup-start Starts the backup processor service.
backup-status Displays the status of the backup processor service.
backup-stop Stops the backup processor service.
gpudb-start Starts the gpudb and gpudb-ha services.
gpudb-status Displays the status of the gpudb and gpudb-ha services.
gpudb-stop Stops the gpudb and gpudb-ha services.
ha-restart Restarts the gpudb-ha service.
ha-start Starts the gpudb-ha service.
ha-status Displays the status of the gpudb-ha service.
ha-stop Stops the gpudb-ha service.
mq-restart Restarts the gpudb-mq service.
mq-status Displays the status of the gpudb-mq service.
mq-start Starts the gpudb-mq service.
mq-stop Stops the gpudb-mq service.
restart Restarts the gpudb-ha and backup processor services.
start Starts the gpudb-ha and backup processor services.
status Displays the status of the gpudb-ha and backup processor services.
stop Stops the gpudb-ha and backup processor services.
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