You can enable [alerting high availability]({{< relref "./_index.md" >}}) support by updating the Grafana configuration file. On Kubernetes, you can enable alerting high availability by updating the Kubernetes container definition.
## Update Grafana configuration file
### Before you begin
Since gossiping of notifications and silences uses both TCP and UDP port `9094`, ensure that each Grafana instance is able to accept incoming connections on these ports.
**To enable high availability support:**
1. In your custom configuration file ($WORKING_DIR/conf/custom.ini), go to the `[unified_alerting]` section.
2. Set `[ha_peers]` to the number of hosts for each Grafana instance in the cluster (using a format of host:port), for example, `ha_peers=10.0.0.5:9094,10.0.0.6:9094,10.0.0.7:9094`.
You must have at least one (1) Grafana instance added to the [`[ha_peer]` section.
3. Set `[ha_listen_address]` to the instance IP address using a format of `host:port` (or the [Pod's](https://kubernetes.io/docs/concepts/workloads/pods/) IP in the case of using Kubernetes).
By default, it is set to listen to all interfaces (`0.0.0.0`).
## Update Kubernetes container definition
If you are using Kubernetes, you can expose the pod IP [through an environment variable](https://kubernetes.io/docs/tasks/inject-data-application/environment-variable-expose-pod-information/) via the container definition such as:
