docker-compose kafka wait for zookeeper and schema-registry wait for kafka

Question

I read Docker (Compose) client connects to Kafka too early, but it doesn't give which command to check.

How should I configure my kafka broker so it retries when zookeeper is not ready? and my schema-registry also fails due to kafka broker is not ready.

my docker-compose file:

  zookeeper:
    image: confluentinc/cp-zookeeper:5.5.3
    hostname: zookeeper
    container_name: zookeeper
    ports:
      - "2181:2181"
    environment:
      ZOOKEEPER_CLIENT_PORT: 2181
      ZOOKEEPER_TICK_TIME: 2000

  broker:
    image: confluentinc/cp-server:5.5.3
    hostname: broker
    container_name: broker
    depends_on:
      - zookeeper
    ports:
      - "9092:9092"
    environment:
      KAFKA_BROKER_ID: 1
      KAFKA_ZOOKEEPER_CONNECT: 'zookeeper:2181'
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: PLAINTEXT:PLAINTEXT,PLAINTEXT_HOST:PLAINTEXT
      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://broker:29092,PLAINTEXT_HOST://localhost:9092
      KAFKA_METRIC_REPORTERS: io.confluent.metrics.reporter.ConfluentMetricsReporter
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
      KAFKA_GROUP_INITIAL_REBALANCE_DELAY_MS: 0
      KAFKA_CONFLUENT_LICENSE_TOPIC_REPLICATION_FACTOR: 1
      CONFLUENT_METRICS_REPORTER_BOOTSTRAP_SERVERS: broker:29092
      CONFLUENT_METRICS_REPORTER_ZOOKEEPER_CONNECT: zookeeper:2181
      CONFLUENT_METRICS_REPORTER_TOPIC_REPLICAS: 1
      CONFLUENT_METRICS_ENABLE: 'true'
      CONFLUENT_SUPPORT_CUSTOMER_ID: 'anonymous'

  schema-registry:
    image: confluentinc/cp-schema-registry:5.5.3
    hostname: schema-registry
    container_name: schema-registry
    depends_on:
      - zookeeper
      - broker
    ports:
      - "8081:8081"
    environment:
      SCHEMA_REGISTRY_HOST_NAME: schema-registry
      SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL: 'zookeeper:2181'

Acclaim

Answer 1

You can make use of the healthcheck, as following

For the broker:

......
healthcheck:
  test: ["CMD", "kafka-topics", "--bootstrap-server", "broker:9092", "--list"]
  interval: 30s
  timeout: 10s
  retries: 10

For the schema registry:

......
healthcheck:
  test: ["CMD", "curl", "--output", "/dev/null", "--silent", "--head", "--fail", "http://schema-registry:8081/subjects"]
  interval: 30s
  timeout: 10s
  retries: 10

Calceolaria