Why is http://localhost:9021/ not opening the Confluent Control Center? - docker

Question

I am working on the Confluent Admin training and running labs in Docker for Desktop. PFA the docker-compose yaml file.
The Confluent Control Center doesn't open in brower. I am using http://localhost:9021 to open. Ealier it used to open but not any more. The only change I have done in my computer is to install McAfee Live Safe. I even tried by turning off the Firewall, but it didn't help either.
Can someone please share if you had similar experience and how you overcame this issue?
docker-compose.yaml file.
version: "3.5"
services:
zk-1:
image: confluentinc/cp-zookeeper:5.3.1
hostname: zk-1
container_name: zk-1
ports:
- "12181:2181"
volumes:
- data-zk-log-1:/var/lib/zookeeper/log
- data-zk-data-1:/var/lib/zookeeper/data
networks:
- confluent
environment:
- ZOOKEEPER_SERVER_ID=1
- ZOOKEEPER_CLIENT_PORT=2181
- ZOOKEEPER_TICK_TIME=2000
- ZOOKEEPER_INIT_LIMIT=5
- ZOOKEEPER_SYNC_LIMIT=2
- ZOOKEEPER_SERVERS=zk-1:2888:3888;zk-2:2888:3888;zk-3:2888:3888
zk-2:
image: confluentinc/cp-zookeeper:5.3.1
hostname: zk-2
container_name: zk-2
ports:
- "22181:2181"
volumes:
- data-zk-log-2:/var/lib/zookeeper/log
- data-zk-data-2:/var/lib/zookeeper/data
networks:
- confluent
environment:
- ZOOKEEPER_SERVER_ID=2
- ZOOKEEPER_CLIENT_PORT=2181
- ZOOKEEPER_TICK_TIME=2000
- ZOOKEEPER_INIT_LIMIT=5
- ZOOKEEPER_SYNC_LIMIT=2
- ZOOKEEPER_SERVERS=zk-1:2888:3888;zk-2:2888:3888;zk-3:2888:3888
zk-3:
image: confluentinc/cp-zookeeper:5.3.1
hostname: zk-3
container_name: zk-3
ports:
- "32181:2181"
volumes:
- data-zk-log-3:/var/lib/zookeeper/log
- data-zk-data-3:/var/lib/zookeeper/data
networks:
- confluent
environment:
- ZOOKEEPER_SERVER_ID=3
- ZOOKEEPER_CLIENT_PORT=2181
- ZOOKEEPER_TICK_TIME=2000
- ZOOKEEPER_INIT_LIMIT=5
- ZOOKEEPER_SYNC_LIMIT=2
- ZOOKEEPER_SERVERS=zk-1:2888:3888;zk-2:2888:3888;zk-3:2888:3888
kafka-1:
image: confluentinc/cp-enterprise-kafka:5.3.1
hostname: kafka-1
container_name: kafka-1
ports:
- "19092:9092"
networks:
- confluent
volumes:
- data-kafka-1:/var/lib/kafka/data
environment:
KAFKA_BROKER_ID: 101
KAFKA_ZOOKEEPER_CONNECT: zk-1:2181,zk-2:2181,zk-3:2181
KAFKA_LISTENERS: DOCKER://kafka-1:9092,HOST://kafka-1:19092
KAFKA_ADVERTISED_LISTENERS: DOCKER://kafka-1:9092,HOST://localhost:19092
KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: DOCKER:PLAINTEXT,HOST:PLAINTEXT
KAFKA_INTER_BROKER_LISTENER_NAME: DOCKER
KAFKA_METRIC_REPORTERS: "io.confluent.metrics.reporter.ConfluentMetricsReporter"
CONFLUENT_METRICS_REPORTER_BOOTSTRAP_SERVERS: "kafka-1:9092,kafka-2:9092,kafka-3:9092"
kafka-2:
image: confluentinc/cp-enterprise-kafka:5.3.1
hostname: kafka-2
container_name: kafka-2
ports:
- "29092:9092"
networks:
- confluent
volumes:
- data-kafka-2:/var/lib/kafka/data
environment:
KAFKA_BROKER_ID: 102
KAFKA_ZOOKEEPER_CONNECT: zk-1:2181,zk-2:2181,zk-3:2181
KAFKA_LISTENERS: DOCKER://kafka-2:9092,HOST://kafka-2:29092
KAFKA_ADVERTISED_LISTENERS: DOCKER://kafka-2:9092,HOST://localhost:29092
KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: DOCKER:PLAINTEXT,HOST:PLAINTEXT
KAFKA_INTER_BROKER_LISTENER_NAME: DOCKER
KAFKA_METRIC_REPORTERS: "io.confluent.metrics.reporter.ConfluentMetricsReporter"
CONFLUENT_METRICS_REPORTER_BOOTSTRAP_SERVERS: "kafka-1:9092,kafka-2:9092,kafka-3:9092"
kafka-3:
image: confluentinc/cp-enterprise-kafka:5.3.1
hostname: kafka-3
container_name: kafka-3
ports:
- "39092:9092"
networks:
- confluent
volumes:
- data-kafka-3:/var/lib/kafka/data
environment:
KAFKA_BROKER_ID: 103
KAFKA_ZOOKEEPER_CONNECT: zk-1:2181,zk-2:2181,zk-3:2181
KAFKA_LISTENERS: DOCKER://kafka-3:9092,HOST://kafka-3:39092
KAFKA_ADVERTISED_LISTENERS: DOCKER://kafka-3:9092,HOST://localhost:39092
KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: DOCKER:PLAINTEXT,HOST:PLAINTEXT
KAFKA_INTER_BROKER_LISTENER_NAME: DOCKER
KAFKA_METRIC_REPORTERS: "io.confluent.metrics.reporter.ConfluentMetricsReporter"
CONFLUENT_METRICS_REPORTER_BOOTSTRAP_SERVERS: "kafka-1:9092,kafka-2:9092,kafka-3:9092"
schema-registry:
image: confluentinc/cp-schema-registry:5.3.1
hostname: schema-registry
container_name: schema-registry
ports:
- "8081:8081"
networks:
- confluent
environment:
SCHEMA_REGISTRY_HOST_NAME: schema-registry
SCHEMA_REGISTRY_KAFKASTORE_BOOTSTRAP_SERVERS: "kafka-1:9092,kafka-2:9092,kafka-3:9092"
SCHEMA_REGISTRY_LISTENERS: "http://schema-registry:8081,http://localhost:8081"
# Uses incorrect container utility belt (CUB) environment variables due to bug.
# See https://github.com/confluentinc/cp-docker-images/issues/807. A fix was merged that
# will be available in the CP 5.4 image.
KAFKA_REST_CUB_KAFKA_TIMEOUT: 120
KAFKA_REST_CUB_KAFKA_MIN_BROKERS: 3
connect:
image: confluentinc/cp-kafka-connect:5.3.1
hostname: connect
container_name: connect
ports:
- "8083:8083"
volumes:
- ./data:/data
networks:
- confluent
environment:
CONNECT_PRODUCER_INTERCEPTOR_CLASSES: io.confluent.monitoring.clients.interceptor.MonitoringProducerInterceptor
CONNECT_CONSUMER_INTERCEPTOR_CLASSES: io.confluent.monitoring.clients.interceptor.MonitoringConsumerInterceptor
CONNECT_BOOTSTRAP_SERVERS: kafka-1:9092,kafka-2:9092,kafka-3:9092
CONNECT_GROUP_ID: "connect"
CONNECT_CONFIG_STORAGE_TOPIC: "connect-config"
CONNECT_OFFSET_STORAGE_TOPIC: "connect-offsets"
CONNECT_STATUS_STORAGE_TOPIC: "connect-status"
CONNECT_KEY_CONVERTER: "io.confluent.connect.avro.AvroConverter"
CONNECT_VALUE_CONVERTER: "io.confluent.connect.avro.AvroConverter"
CONNECT_KEY_CONVERTER_SCHEMA_REGISTRY_URL: "http://schema-registry:8081"
CONNECT_VALUE_CONVERTER_SCHEMA_REGISTRY_URL: "http://schema-registry:8081"
CONNECT_INTERNAL_KEY_CONVERTER: org.apache.kafka.connect.json.JsonConverter
CONNECT_INTERNAL_VALUE_CONVERTER: org.apache.kafka.connect.json.JsonConverter
CONNECT_REST_ADVERTISED_HOST_NAME: "connect"
CONNECT_LOG4J_ROOT_LOGLEVEL: INFO
CONNECT_LOG4J_LOGGERS: org.reflections=ERROR
CONNECT_PLUGIN_PATH: /usr/share/java
CONNECT_REST_HOST_NAME: "connect"
CONNECT_REST_PORT: 8083
CONNECT_CUB_KAFKA_TIMEOUT: 120
ksql-server:
image: confluentinc/cp-ksql-server:5.3.1
hostname: ksql-server
container_name: ksql-server
ports:
- "8088:8088"
networks:
- confluent
environment:
KSQL_CONFIG_DIR: "/etc/ksql"
KSQL_LOG4J_OPTS: "-Dlog4j.configuration=file:/etc/ksql/log4j-rolling.properties"
KSQL_BOOTSTRAP_SERVERS: kafka-1:9092,kafka-2:9092,kafka-3:9092
KSQL_HOST_NAME: ksql-server
KSQL_APPLICATION_ID: "etl-demo"
KSQL_LISTENERS: "http://0.0.0.0:8088"
# Set the buffer cache to 0 so that the KSQL CLI shows all updates to KTables for learning purposes.
# The default is 10 MB, which means records in a KTable are compacted before showing output.
# Change cache.max.bytes.buffering and commit.interval.ms to tune this behavior.
KSQL_CACHE_MAX_BYTES_BUFFERING: 0
KSQL_KSQL_SCHEMA_REGISTRY_URL: "http://schema-registry:8081"
KSQL_PRODUCER_INTERCEPTOR_CLASSES: "io.confluent.monitoring.clients.interceptor.MonitoringProducerInterceptor"
KSQL_CONSUMER_INTERCEPTOR_CLASSES: "io.confluent.monitoring.clients.interceptor.MonitoringConsumerInterceptor"
control-center:
image: confluentinc/cp-enterprise-control-center:5.3.1
hostname: control-center
container_name: control-center
restart: always
networks:
- confluent
ports:
- "9021:9021"
environment:
CONTROL_CENTER_BOOTSTRAP_SERVERS: kafka-1:9092,kafka-2:9092,kafka-3:9092
CONTROL_CENTER_ZOOKEEPER_CONNECT: zk-1:2181,zk-2:2181,zk-3:2181
CONTROL_CENTER_STREAMS_NUM_STREAM_THREADS: 4
CONTROL_CENTER_REPLICATION_FACTOR: 3
CONTROL_CENTER_CONNECT_CLUSTER: "connect:8083"
CONTROL_CENTER_KSQL_URL: "http://ksql-server:8088"
CONTROL_CENTER_KSQL_ADVERTISED_URL: "http://localhost:8088"
CONTROL_CENTER_SCHEMA_REGISTRY_URL: "http://schema-registry:8081"
tools:
image: cnfltraining/training-tools:5.3
hostname: tools
container_name: tools
volumes:
- ${PWD}/:/apps
working_dir: /apps
networks:
- confluent
command: /bin/bash
tty: true
volumes:
data-zk-log-1:
data-zk-data-1:
data-zk-log-2:
data-zk-data-2:
data-zk-log-3:
data-zk-data-3:
data-kafka-1:
data-kafka-2:
data-kafka-3:
networks:
confluent:
All the docker containers are up and running; all respective confluent services are up.
Thanks !!

Answer 1

Finally...I got an answer to this from Confluent Support.
The version of control center in the labs expires after 30 days.
This can reset by removing all the containers and volumes on the PC.
docker-compose down -v will exit and remove all the containers and volumes.
Re-run the docker-compose up -d command.
Now give a minute or two before opening the Control Center in any browser.
P.S. Docker should have been given at least 6GB of memory to run all the containers.
Thanks.