Alerts rules are configurable in Lenses, alerts that are generated can then be sent to specific channels. Several different integration points are available for channels.

Infrastructure alerts

These are a set of built-in alerting rules for the core connections, Kafka, Schema Registry, Zookeeper, and Kafka Connect. See infrastructure health.

Data Produced Alerts

Data produced are user-defined alerts on the amount of data on a topic over time. Users have a choice to notify if the topic receives either:

1. more than

2. or less than

Consumer lag alerts

Consumer rules are alerting on consumer group lag. Users can define:

1. a lag

2. on a topic

3. for a consumer group

4. which channels to send an alert to

Application alerts

Lenses allows operators to configure alerting on Connectors. Operators can:

1. Set channels to send alerts to

2. Enable auto restart of connector tasks. Lenses will restart failed tasks with a grace period.

The sequence is:

1. Lenses watches for task failures.

2. If a task fails, Lenses will restart it.

3. If the restart is successful Lenses resets the "restart attempts" back to zero

4. If the restart is not successful, Lenses increments the restart attempts, waits for the grace period and tries another restart if the task is still in a failed state.

Steps 4 is repeated until restart attempts is reached. Lenses will only rest the restart attempts to zero after the tasks have been brought back to a healthy start by manual intervention.

The number of times Lenses attempts to restart is based on the entry in the alert setting.

The restart attempts can be tracked in the Audits page.

Viewing alert events

To view events go to Environments->[Your Environment]->Admin -> Alerts -> Events.

Consumer group monitoring is a key part of operating Kafka. Lenses allows operators to view and manage consumer groups.

Viewing consumer groups

To view consumer groups and the max and min lag across the partitions go to Environments->[Your Environment]->Workspace->Monitor->Consumers. You can also see this information for each topic in the Environments->[Your Environment]->Explore screen->Select topic->Partition tab.

View consumer group details

Select, or search for a consumer group, you can also search for consumer groups that are not active.

Viewing alerts for a consumer group

To view alerts for a consumer group, click the view alerts button. Resetting consumer groups is only possible if the consumer group is not active. i.e. the application must be stopped, such as a Connector or SQL Processor. Enable the show inactive consumers to find them.​​

Resetting consumer group for a specific partition to an offset

1. Select the consumer group

2. Select the partition to reset the offsets for

3. Specify the offset

Resetting the whole consumer group

To reset a consumer group (all clients in the group), select the consumer groups, select Actions, and Change Multiple offsets. This will reset all clients in the consumer group to either:

1. To the start

2. To the last offset

3. To a specific timestamp