How to enable HA for Alertmanager in Rancher lanched Monitoring

Article Number: 000020009

Situation

Task

To increase the replica count of the alertmanager pod and enable HA so that if the node with the Alertmanager pod dies, alerts will still function.
Increasing the replica count in the chart is the only change required as alerts are sent to ALL the alertmanager pods. They communicate to each other which alerts have already been dispatched, so they are not duplicated.

Pre-requisites

• Running Rancher v2.7.x/v2.8.x
• Monitoring deployed via Rancher Apps & Marketplace

Resolution

You can enable HA alertmanager by increasing the replica count in the chart.

1. Go to Monitoring Chart in the Apps Marketplace
   
2. Under Chart Options, click on the Edit as YAML button
   
3. In the alertmanager block, modify replicas to your preference. Here it is set to 2
   
4. Click on Upgrade button to apply changes
   

Further reading

• Alerting chart user-guide