Use this procedure for the following use cases:
- If you want to provision HSNs after deploying an instance. For this use case, no changes to your auto scaling permissions are required.
- If you deployed an instance prior to Teradata Software for AWS 5.02, performed a software upgrade, and want to provision HSNs. For this use case, ask your IAM administrator to grant you the following permissions as a new auto scaling group is created as part of this procedure:
- autoscaling:CreateAutoScalingGroup
- autoscaling:CreateLaunchConfiguration
- autoscaling:DeleteLaunchConfiguration
There is a higher risk of failure when provisioning HSNs after deployment. Resource issues sometimes prevent AWS from provisioning resources. AWS automatically retries provisioning until successful.
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Type the following command from a Teradata Database node to determine if any HSNs are currently configured.
# tdc-hot-standby --hsn-status
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Type the following command to provision up to 2 HSNs.
# tdc-hot-standby -m nwhere n is the number of HSNs you want to provision. -
Type the following command to get status as the HSNs are being launched and configured.
# tdc-hot-standby --hsn-status
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If the image is out of date or the instance type of the HSNs is different than the instance type of the node, type the following command to update the HSNs.
# tdc-hot-standby -u
The auto scaling group is updated accordingly. -
[Optional] Type the command again to confirm the HSNs are up to date.
# tdc-hot-standby --hsn-status
After provisioning HSNs, you do not need to stop and restart the Teradata Database. -
If resource issues are preventing AWS from provisioning resources for the HSNs and you want to back out of the process, type the following command to stop the AWS provisioning process.
# tdc-hot-standby -m 0
Teradata recommends not backing out of this process as there is no cost associated until the HSNs are provisioned.
You can monitor the provisioning process from the EC2 console.
- HSNs are all named stack name-hsn on deployment. For example, if the stack name is mydbs, the HSNs are named mydbs-hsn.
- From the Tags tab, you can identify the HSN with a key of HSN and a value that represents the status. The status initially displays Configuring.
- The status changes to Ready when the HSN is ready for use.
- When a node fails, the HSN attaches to the failed node and the status of the HSN changes to In-Use.
- Another HSN automatically deploys to replace the HSN that was put in use. It sits idle and does not go into service until another node fails.