# org.apache.kafka.connect.errors.ConnectException: Exceeded max number of retries. Topic 'my_topic' partition 0, offset 12345: Elasticsearch cluster unavailable

- **ID:** `kafka/elasticsearch-sink-connector-backoff`
- **Domain:** kafka
- **Category:** runtime_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

Kafka Connect Elasticsearch sink connector exhausted retries due to Elasticsearch cluster being unreachable or overloaded, causing task failure.

## Workarounds

1. **Check Elasticsearch cluster health and restart it if necessary. Use `curl -X GET 'localhost:9200/_cluster/health?pretty'` to verify status.** (80% success)
   ```
   Check Elasticsearch cluster health and restart it if necessary. Use `curl -X GET 'localhost:9200/_cluster/health?pretty'` to verify status.
   ```
2. **Increase 'retry.backoff.ms' in connector config to a higher value (e.g., 10000 ms) and ensure 'max.retries' is reasonable (e.g., 10). This gives Elasticsearch more time to recover.** (75% success)
   ```
   Increase 'retry.backoff.ms' in connector config to a higher value (e.g., 10000 ms) and ensure 'max.retries' is reasonable (e.g., 10). This gives Elasticsearch more time to recover.
   ```
3. **If Elasticsearch is temporarily down, pause the connector using `curl -X PUT 'http://localhost:8083/connectors/my-connector/pause'` and resume after restoring Elasticsearch.** (90% success)
   ```
   If Elasticsearch is temporarily down, pause the connector using `curl -X PUT 'http://localhost:8083/connectors/my-connector/pause'` and resume after restoring Elasticsearch.
   ```

## Dead Ends

- **** — This only delays failure; if Elasticsearch is truly down, retries will eventually exhaust and the connector will still fail, potentially filling logs. (60% fail)
- **** — The underlying Elasticsearch connectivity issue persists, so the new connector will encounter the same error. (90% fail)
- **** — The issue is not load but connectivity; reducing tasks doesn't fix the Elasticsearch unavailability. (70% fail)