Elasticsearch connector fails to start - timing issue?

[rmoff]

cp-demo 5.5.1
Startup from scratch using ./scripts/start.sh

elasticsearch-ksqldb connector fails to start. Worker log shows

HttpHostConnectException: Connect to elasticsearch:9200 [elasticsearch/192.168.128.11] failed: Connection refused (Connection refused)

Elasticsearch is running, and if I restart the connector it comes up fine, so I guess this is a timing error.

docker-compose exec connect curl -X POST --cert /etc/kafka/secrets/connect.certificate.pem --key /etc/kafka/secrets/connect.key --tlsv1.2 --cacert /etc/kafka/secrets/snakeoil-ca-1.crt -u superUser:superUser https://connect:8083/connectors/elasticsearch-ksqldb/tasks/0/restart

Starts fine:

docker-compose exec connect curl -X GET --cert /etc/kafka/secrets/connect.certificate.pem --key /etc/kafka/secrets/connect.key --tlsv1.2 --cacert /etc/kafka/secrets/snakeoil-ca-1.crt -u superUser:superUser https://connect:8083/connectors/elasticsearch-ksqldb/status | jq -r ".connector.state, .tasks[].state"
RUNNING
RUNNING

To avoid this problem the startup script could poll Elasticsearch for readiness e.g. / e.g.