Windows 11: can't run the uc-iot locally

[grab7777]

Reproduce

1. start podman env. podman compose up -d
2. wait a few minutes until all containers are running
3. cd uc-iot/kafka-stream
4. mvn compile
5. mvn spring-boot:run

Actual

There are endless error messages, indicating no cluster id and rebootstrapping constantly:

2026-03-18T17:29:48.390+01:00  INFO 19352 --- [751dcdd55-admin] o.a.k.c.a.i.AdminMetadataManager         : [AdminClient clientId=iot-kafka-stream-c6f8479b-01da-47f6-aeb8-a33751dcdd55-admin] Rebootstrapping with Cluster(id = null, nodes = [localhost:9092 (id: -1 rack: null isFenced: false)], partitions = [], controller = null)
2026-03-18T17:29:48.391+01:00  INFO 19352 --- [751dcdd55-admin] o.a.k.c.a.i.AdminMetadataManager         : [AdminClient clientId=iot-kafka-stream-c6f8479b-01da-47f6-aeb8-a33751dcdd55-admin] Rebootstrapping with Cluster(id = null, nodes = [localhost:9092 (id: -1 rack: null isFenced: false)], partitions = [], controller = null)
2026-03-18T17:29:48.392+01:00  INFO 19352 --- [751dcdd55-admin] o.a.k.c.a.i.AdminMetadataManager         : [AdminClient clientId=iot-kafka-stream-c6f8479b-01da-47f6-aeb8-a33751dcdd55-admin] Rebootstrapping with Cluster(id = null, nodes = [localhost:9092 (id: -1 rack: null isFenced: false)], partitions = [], controller = null)
2026-03-18T17:29:48.392+01:00  INFO 19352 --- [751dcdd55-admin] o.a.k.c.a.i.AdminMetadataManager         : [AdminClient clientId=iot-kafka-stream-c6f8479b-01da-47f6-aeb8-a33751dcdd55-admin] Rebootstrapping with Cluster(id = null, nodes = [localhost:9092 (id: -1 rack: null isFenced: false)], partitions = [], controller = null)
2026-03-18T17:29:48.393+01:00  INFO 19352 --- [751dcdd55-admin] o.a.k.c.a.i.AdminMetadataManager         : [AdminClient clientId=iot-kafka-stream-c6f8479b-01da-47f6-aeb8-a33751dcdd55-admin] Rebootstrapping with Cluster(id = null, nodes = [localhost:9092 (id: -1 rack: null isFenced: false)], partitions = [], controller = null)
2026-03-18T17:29:48.393+01:00  INFO 19352 --- [751dcdd55-admin] o.a.k.c.a.i.AdminMetadataManager         : [AdminClient clientId=iot-kafka-stream-c6f8479b-01da-47f6-aeb8-a33751dcdd55-admin] Rebootstrapping with Cluster(id = null, nodes = [localhost:9092 (id: -1 rack: null isFenced: false)], partitions = [], controller = null)
2026-03-18T17:29:48.393+01:00  INFO 19352 --- [751dcdd55-admin] o.a.k.c.a.i.AdminMetadataManager         : [AdminClient clientId=iot-kafka-stream-c6f8479b-01da-47f6-aeb8-a33751dcdd55-admin] Rebootstrapping with Cluster(id = null, nodes = [localhost:9092 (id: -1 rack: null isFenced: false)], partitions = [], controller = null)
2026-03-18T17:29:48.393+01:00  INFO 19352 --- [751dcdd55-admin] o.a.k.c.a.i.AdminMetadataManager         : [AdminClient clientId=iot-kafka-stream-c6f8479b-01da-47f6-aeb8-a33751dcdd55-admin] Rebootstrapping with Cluster(id = null, nodes = [localhost:9092 (id: -1 rack: null isFenced: false)], partitions = [], controller = null)

Should

Kafka messages should be processed by the stream application
Doing the same on MacOS, I get the following expected output:

2026-03-19T08:05:40.050+01:00  INFO 7708 --- [-StreamThread-1] o.a.kafka.common.config.AbstractConfig   : KafkaAvroDeserializerConfig values: 
        auto.register.schemas = true
        avro.reflection.allow.null = false
        avro.use.logical.type.converters = false
        basic.auth.credentials.source = URL
        basic.auth.user.info = [hidden]
        bearer.auth.cache.expiry.buffer.seconds = 300
        bearer.auth.client.id = null
        bearer.auth.client.secret = null
        bearer.auth.credentials.source = STATIC_TOKEN
        bearer.auth.custom.provider.class = null
        bearer.auth.identity.pool.id = null
        bearer.auth.issuer.endpoint.url = null
        bearer.auth.logical.cluster = null
        bearer.auth.scope = null
        bearer.auth.scope.claim.name = scope
        bearer.auth.sub.claim.name = sub
        bearer.auth.token = [hidden]
        context.name.strategy = class io.confluent.kafka.serializers.context.NullContextNameStrategy
        http.connect.timeout.ms = 60000
        http.read.timeout.ms = 60000
        id.compatibility.strict = true
        key.subject.name.strategy = class io.confluent.kafka.serializers.subject.TopicNameStrategy
        latest.cache.size = 1000
        latest.cache.ttl.sec = -1
        latest.compatibility.strict = true
        max.schemas.per.subject = 1000
        normalize.schemas = false
        proxy.host = 
        proxy.port = -1
        rule.actions = []
        rule.executors = []
        rule.service.loader.enable = true
        schema.format = null
        schema.reflection = false
        schema.registry.basic.auth.user.info = [hidden]
        schema.registry.ssl.cipher.suites = null
        schema.registry.ssl.enabled.protocols = [TLSv1.2, TLSv1.3]
        schema.registry.ssl.endpoint.identification.algorithm = https
        schema.registry.ssl.engine.factory.class = null
        schema.registry.ssl.key.password = null
        schema.registry.ssl.keymanager.algorithm = SunX509
        schema.registry.ssl.keystore.certificate.chain = null
        schema.registry.ssl.keystore.key = null
        schema.registry.ssl.keystore.location = null
        schema.registry.ssl.keystore.password = null
        schema.registry.ssl.keystore.type = JKS
        schema.registry.ssl.protocol = TLSv1.3
        schema.registry.ssl.provider = null
        schema.registry.ssl.secure.random.implementation = null
        schema.registry.ssl.trustmanager.algorithm = PKIX
        schema.registry.ssl.truststore.certificates = null
        schema.registry.ssl.truststore.location = null
        schema.registry.ssl.truststore.password = null
        schema.registry.ssl.truststore.type = JKS
        schema.registry.url = [http://myVMsIP:8081, http://localhost:8081]
        specific.avro.key.type = null
        specific.avro.reader = true
        specific.avro.value.type = null
        use.latest.version = false
        use.latest.with.metadata = null
        use.schema.id = -1
        value.subject.name.strategy = class io.confluent.kafka.serializers.subject.TopicNameStrategy

2026-03-19T08:05:40.051+01:00  INFO 7708 --- [-StreamThread-1] o.a.k.s.processor.internals.StreamTask   : stream-thread [iot-kafka-stream-9d0d3ad3-9e23-433e-8031-28d429c5aae2-StreamThread-1] task [0_0] Restored and ready to run
2026-03-19T08:05:40.051+01:00  INFO 7708 --- [-StreamThread-1] o.a.k.s.p.internals.StreamThread         : stream-thread [iot-kafka-stream-9d0d3ad3-9e23-433e-8031-28d429c5aae2-StreamThread-1] State transition from PARTITIONS_ASSIGNED to RUNNING
2026-03-19T08:05:40.051+01:00  INFO 7708 --- [-StreamThread-1] org.apache.kafka.streams.KafkaStreams    : stream-client [iot-kafka-stream-9d0d3ad3-9e23-433e-8031-28d429c5aae2] State transition from REBALANCING to RUNNING
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::objectFieldOffset has been called by com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper (file:/Users/xxx/.m2/repository/com/google/guava/guava/32.0.1-jre/guava-32.0.1-jre.jar)
WARNING: Please consider reporting this to the maintainers of class com.google.common.util.concurrent.AbstractFuture$UnsafeAtomicHelper
WARNING: sun.misc.Unsafe::objectFieldOffset will be removed in a future release
2026-03-19T08:05:40.146+01:00  INFO 7708 --- [-StreamThread-1] c.z.t.kafka.iot.stream.Exercise0Stream   : Processing message with key=myMotor and value=running
2026-03-19T08:05:40.146+01:00  INFO 7708 --- [-StreamThread-1] c.z.t.kafka.iot.stream.Exercise0Stream   : Processing message with key=mySensor and value=77209
2026-03-19T08:05:40.146+01:00  INFO 7708 --- [-StreamThread-1] c.z.t.kafka.iot.stream.Exercise0Stream   : Processing message with key=myMotor and value=stopping
2026-03-19T08:05:40.146+01:00  INFO 7708 --- [-StreamThread-1] c.z.t.kafka.iot.stream.Exercise0Stream   : Processing message with key=mySensor and value=787770

Apache Maven 3.9.12 (848fbb4bf2d427b72bdb2471c22fced7ebd9a7a1)
Maven home: C:\Users\xxx\AppData\Local\mise\installs\maven\3.9.12\apache-maven-3.9.12
Java version: 24.0.2, vendor: Oracle Corporation, runtime: C:\Users\xxx\AppData\Local\mise\installs\java\24.0.2
Default locale: de_CH, platform encoding: UTF-8
OS name: "windows 11", version: "10.0", arch: "amd64", family: "windows"

[mgra-zlk]

things to try:

• test connection Test-NetConnection -ComputerName localhost -Port 29092
• use spring.kafka.bootstrap-servers=host.containers.internal:29092 (podman) or spring.kafka.bootstrap-servers=host.docker.internal:29092 (docker)
• change to bootstrap-servers: 127.0.0.1:29092 (also change KAFKA_ADVERTISED_LISTENERS to PLAINTEXT_HOST://127.0.0.1:29092

[grab7777]

Changing environment in docker-compose.yml to

KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://broker:9092,PLAINTEXT_CLOUD://myVMsIP:9094,PLAINTEXT_HOST://127.0.0.1:29092

and application.yaml to the following, does the trick:

spring:
  kafka:
    bootstrap-servers: myVMsIP:9094,127.0.0.1:29092
    streams:
      application-id: iot-kafka-stream
      properties:
        schema.registry.url: http://myVMsIP:8081,http://127.0.0.1:8081
        auto.offset.reset: earliest
        default.key.serde: org.apache.kafka.common.serialization.Serdes$StringSerde
        default.value.serde: io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde

PS G:\Git\kafka-streaming-technology> Test-NetConnection -ComputerName localhost -Port 29092
WARNING: TCP connect to (::1 : 29092) failed

ComputerName     : localhost
RemoteAddress    : 127.0.0.1
RemotePort       : 29092
InterfaceAlias   : Loopback Pseudo-Interface 1
SourceAddress    : 127.0.0.1
TcpTestSucceeded : True

PS G:\Git\kafka-streaming-technology> Test-NetConnection -ComputerName 127.0.0.1 -Port 29092

ComputerName     : 127.0.0.1
RemoteAddress    : 127.0.0.1
RemotePort       : 29092
InterfaceAlias   : Loopback Pseudo-Interface 1
SourceAddress    : 127.0.0.1
TcpTestSucceeded : True

[mgra-zlk]

This has to be checked also in the security lab.

• not fixed on some devices, check /etc/hosts entries -> 127.0.0.1 localhost

[grab7777]

instead of doing that #16 (comment), the issue was also solved with adding 127.0.0.1 localhost to C:\Windows\System32\drivers\etc\hosts on my machine, as suggested above.

  127.0.0.1    localhost
# ::1          localhost
  192.168.1.26 host.docker.internal
  192.168.1.26 gateway.docker.internal
  127.0.0.1    kubernetes.docker.internal