how to change strimzi dns cache ttl for connect

[jorgebo10]

Hi,
Is it possible to configure networkaddress.cache.ttl in Strimzi 0.34.0 for a KafkaConnector. I have found STRIMZI_DNS_CACHE_TTL but not sure how to check if it works.
Thanks

[scholzj]

I think STRIMZI_DNS_CACHE_TTL applies only to the Cluster and User Operators. Not to any operands.

[scholzj]

I do not think you need to add it anywhere. You can just specify the Java system properties to configure it directly.

[jorgebo10]

cool, i went over the source code https://github.com/strimzi/strimzi-kafka-operator/blob/main/user-operator/src/main/java/io/strimzi/operator/user/Main.java and then i set the following config up:

jvmOptions:
   javaSystemProperties:
     - name: STRIMZI_DNS_CACHE_TTL
       value: "0"
     - name: javax.net.debug
       value: ssl

and noticed that env of my pod was updated:

{
                        "name": "STRIMZI_JAVA_SYSTEM_PROPERTIES",
                        "value": "-DSTRIMZI_DNS_CACHE_TTL=0 -Djavax.net.debug=ssl"
                    },

[scholzj]

But the systme property -DSTRIMZI_DNS_CACHE_TTL has no meaning. You have to use the Java system property that will be consumed by Java - I guess networkaddress.cache.ttl, but you should doublecheck that in Java probably.

[jorgebo10]

i think that it is pass through this

strimzi-kafka-operator/user-operator/src/main/java/io/strimzi/operator/user/Main.java

Line 71 in 8a17029

String dnsCacheTtl = System.getenv("STRIMZI_DNS_CACHE_TTL") == null ? "30" : System.getenv("STRIMZI_DNS_CACHE_TTL");

[scholzj]

No, this is the User Operator code. As I said, for the User and Cluster operators, you can use the STRIMZI_DNS_CACHE_TTL environment variable. But for the other components, you have use the Java system properties. The one I mentioned above is what the Cluster and User OPerator use for themselves. But to be honest, I do not know if that applies to all Java applications etc.