Troubleshooting local instance of kafka

Command line kafka utilities

If your rails server or consumer cannot connect to Kafka locally you can try using the command line utilities included with kafka to diagnose whether your kafka is set up properly:

Create a topic:

⚡  kafka-topics --create --partitions 1 --replication-factor 1 --topic new-test-topic --bootstrap-server 127.0.0.1:9092

Created topic new-test-topic.

Describe the created topic:

⚡  kafka-topics --describe --topic new-test-topic --bootstrap-server 127.0.0.1:9092

Topic: new-test-topic   TopicId: BnpzD0HXTXGtidmVxGbNuw PartitionCount: 1       ReplicationFactor: 1    Configs: segment.bytes=1073741824
        Topic: new-test-topic   Partition: 0    Leader: 0       Replicas: 0     Isr: 0

Start writing events to the topic:

⚡  kafka-console-producer --topic new-test-topic --bootstrap-server 127.0.0.1:9092
>

(then write some messages and press enter between each):

> i-typed-this-message-1
>i-typed-this-message-2

(press Ctrl-C when you are done)

Then start a consumer to read the messages you created:

⚡  kafka-console-consumer --topic new-test-topic --from-beginning --bootstrap-server 127.0.0.1:9092
 i-typed-this-message-1
i-typed-this-message-2

(press CTRL-C to exit the consumer process)

If all of these work then check that your config/delivery_boy.yml, config/racecar.yml, .env are configured correctly with each other.

If the commands kafka-topics, kafka-console-producer etc. are not found

• If you installed with brew, you might need to prefix the command: $(brew --prefix kafka)/bin/kafka-topics --create..., or add $(brew --prefix kafka)/bin to your path.
• If you installed in some other way you will need to run bin/kafka-topics ... from the kafka installation directory, or add it to your path.

Check if the server is running on the port you expect

Check if there is anything running on the port you expect (e.g. 9092):

lsof -i :9092

If there is no output, either the server is not running, or it is listening to a different port.

Check if the server is running

Check if the server is running, e.g. using ps -ef | grep kafka.

Homebrew

If you installed kafka using brew and followed the post install instructions to run brew services start kafka:

Check if brew started the service

(assuming you set kafka up to run as a service using brew services start kafka):

brew services info kafka

example output:

kafka (homebrew.mxcl.kafka)
Running: ✔
Loaded: ✔
Schedulable: ✘
User: frederickmeissner
PID: 1664

or

brew services list

example output:

Name                  Status  User              File
dbus                  none
kafka                 started frederickmeissner ~/Library/LaunchAgents/homebrew.mxcl.kafka.plist
[email protected] started frederickmeissner ~/Library/LaunchAgents/[email protected]
[email protected]             started frederickmeissner ~/Library/LaunchAgents/[email protected]
postgresql            started frederickmeissner ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
postgresql@13         none
redis                 started frederickmeissner ~/Library/LaunchAgents/homebrew.mxcl.redis.plist
unbound               none
zookeeper             started frederickmeissner ~/Library/LaunchAgents/homebrew.mxcl.zookeeper.plist

(you should see kafka listed if you started it using brew services start kafka)

Find the logs

Brew may have started the service, but something has gone wrong. You might need more info from the logs

To find the log file examine the service file, e.g.:

cat $(brew --prefix)/Cellar/kafka/3.0.0/homebrew.kafka.service

example output:

[Unit]
Description=Homebrew generated unit for kafka

[Install]
WantedBy=multi-user.target

[Service]
Type=simple
ExecStart=/opt/homebrew/opt/kafka/bin/kafka-server-start /opt/homebrew/etc/kafka/server.properties
Restart=always
WorkingDirectory=/opt/homebrew
StandardOutput=append:/opt/homebrew/var/log/kafka/kafka_output.log
StandardError=append:/opt/homebrew/var/log/kafka/kafka_output.log%

View the logs

View the logs, e.g. less $(brew --prefix)/var/log/kafka/kafka_output.log for more info.