Standalone confluent schema registry not starting

Schema Registry
1

I see below error in my /var/log when I start Standalone schema registry. I have the Apache Zookeeper and Kafka server up and running. I have java location in profile path and java home variables.

[Oct 5 16:18:18 chn-vm-operaxd1 systemd: Started RESTful Avro schema registry for Apache Kafka.
Oct 5 16:18:18 chn-vm-operaxd1 schema-registry-start: /usr/bin/schema-registry-run-class: line 174: exec: java: not found
Oct 5 16:18:18 chn-vm-operaxd1 systemd: confluent-schema-registry.service: main process exited, code=exited, status=127/n/a
Oct 5 16:18:18 chn-vm-operaxd1 systemd: Unit confluent-schema-registry.service entered failed state.
Oct 5 16:18:18 chn-vm-operaxd1 systemd: confluent-schema-registry.service failed.

2

Hi @ravikumaraju,

What user are you starting it as, and does that user have JAVA_HOME configured properly? Double check that $JAVA_HOME/bin/java -version succeeds when run as that user.

What deployment method are you using for ZooKeeper, Kafka, and Schema Registry? i.e., which docs page are you following?

HTH,
Dave

3

Hi Dave,
Thank you for your response,
I’m starting the schema registry service as root user.
I double checked and the $JAVA_HOME is configured properly, below is the output from root user,

$JAVA_HOME/bin/java -version
java version “11.0.7” 2020-04-14 LTS
Java™ SE Runtime Environment 18.9 (build 11.0.7+8-LTS)
Java HotSpot™ 64-Bit Server VM 18.9 (build 11.0.7+8-LTS, mixed mode)

Yes, the deployment method is ZooKeeper, Kafka and Schema Registry. I have the ZooKeper and Kafka server up and running.

The document page I’m following is,

When I run the step 6 ( Start Schema Registry), I’m getting my error (confluent-schema-registry.service failed.) .

Regards
Ravi

4

Hi Ravi,

I’d recommend following the latest docs from Confluent here.

This still seems like a java install / config issue. Since the service runs as cp-schema-registry:

# cat /lib/systemd/system/confluent-schema-registry.service

...

[Service]
Type=simple
User=cp-schema-registry
Group=confluent

...

You might ensure that java works for that user, e.g.:

# sudo su -l cp-schema-registry -s /bin/bash
Last login: Fri Oct 20 20:47:01 UTC 2023 on pts/0

[cp-schema-registry@localhost ~]$ java -version
openjdk version "11.0.21" 2023-10-17 LTS
OpenJDK Runtime Environment (Red_Hat-11.0.21.0.9-1) (build 11.0.21+9-LTS)
OpenJDK 64-Bit Server VM (Red_Hat-11.0.21.0.9-1) (build 11.0.21+9-LTS, mixed mode, sharing)

HTH,
Dave

5

Hi Dave,
I’m able to verify that the Java works for cp-schema-registry user, here is the output,

image

Do you think it probably has issue with java version I have installed ? Is there a recommended java version for schema registry.

Thank you for your valuable inputs.

Regards
Ravi

6

Hi Ravi,

That version of Java is OK. Java 17 is recommended but 8 and 11 are also supported.

Did you start from scratch following the Confluent docs? If you haven’t, I’d recommend doing that (and installing v 7.5) since I see some differences between the latest docs and this page that you were following.

Another thing you could try is to explicitly set JAVA_HOME in /lib/systemd/system/confluent-schema-registry.service. For example, if the java executable is located at /usr/lib/jvm/java-11-openjdk-11.0.21.0.9-2.el9.x86_64/bin/java, you’d add this line to the service file:

Environment="JAVA_HOME=/usr/lib/jvm/java-11-openjdk-11.0.21.0.9-2.el9.x86_64/"

Then run systemctl daemon-reload to reload the service definition and then try starting Schema Registry again.

Dave