Read-Only mode

Sometimes, you want to be sure that you won't misclick anywhere or you just want to access Conduktor in read-only mode (useful for Testers, Product Owners, Data Analysts etc.).

Conduktor does not have a proper permissions system for now (contact us if that matters to you, we may do that for enterprises) and offer instead a quick toggleable read-only mode:

• Not Read-Only: we can produce data, have access to advanced commands, can delete topic...

• With Read-Only enabled: less features are visible, your resources are safe!

Conduktor's Settings

Conduktor comes with many options (and growing) to customize its behaviour. This is important when it comes to large clusters: you don't need everything, so better remove some useless overhead.

It's also there to configure:

• the Kafka clients used across Conduktor (administration, consumer, producer...)

  • Increase the timeouts if your cluster or connection is slow (default is 30s)

  • Does that ring a bell? org.apache.kafka.common.errors.TimeoutException: Failed to update metadata after 30000 ms.

• a few Kafka Streams options

Go Options > Settings:

We can decide which columns to hide or show. When columns are hidden, processing is not done (like with "Show Last Write" which can be quite expensive if you have many topics, it's a good idea to hide it).

JVM (Advanced)

It's possible to grab some stats about the JVM (read-only!):

It's mostly for advanced users who understand what's going on.

By default, Conduktor is limited to 2GB of memory heap. It's possible to increase this and alter any Java configuration by editing the configuration file yourself:

• MacOS: /Applications/Conduktor.app/Contents/app/Conduktor.cfg

• Windows

• Linux: /opt/conduktor/lib/app/Conduktor.cfg

The default options are:

[JavaOptions]
-Xms128m
-Xmx2048m
-Dsun.io.useCanonPrefixCache=false
-Djava.net.preferIPv4Stack=true
-XX:+HeapDumpOnOutOfMemoryError
-XX:+UseCompressedOops
-Dfile.encoding=UTF-8

Custom environment variables

It's possible to customize the -D* without losing them when upgrading.

Instead of playing with Conduktor.cfg, create the file conduktor.vmoptions in your Conduktor personal folder and add as many "-D" as you want (only -D, no -XX), to set them when Conduktor starts (only on startup, it's not taken into account after):

• MacOS: /Users/<user>/Library/Application Support/conduktor/conduktor.vmoptions

• Windows: C:\Users\<user>\AppData\Local\conduktor\conduktor\conduktor.vmoptions

• Linux: /home/<user>/.config/conduktor/conduktor.vmoptions (or XDG Config path if set)

Example:

-Djava.net.preferIPv4Stack=false
-Dhttp.proxyHost=1.2.3.4
-Djava.security.auth.login.config=/tmp/kafka_jaas.conf

Custom .jars

Right now, Conduktor does not offer an interface to do this. But it's possible, by doing a few manual things! Let's say you want to configure your Kafka connection with a custom configuration such as sasl.login.callback.handler.class.

• Copy your .jar to Conduktor installation folder

• Add your .jar path to Conduktor.cfg (app.classpath) to take it into account

• ⚠️ Be aware that you will LOSE these modifications when upgrading Conduktor (we update the configuration file so your modifications are overriden)

Logs

Kafka logging

Conduktor logs all Kafka client warnings and errors to a file, directly accessible from the Conduktor interface.

• Go to the Cluster Configuration screen

• Test Kafka Connectivity

• Click on "Logs"

A popup will open with the logs and the path to the kafka.log file:

Conduktor logging

Starting Conduktor 2.7.0, we log everything into a conduktor.log file. This may help to troubleshoot odd behaviour, connection issues and so on.

• Windows: C:\Users\<User>\AppData\Local\Temp\conduktor.log

• Linux: /tmp/conduktor.log

• macOS: /var/folders/wy/xxx/T/conduktor.log

  • the path is random. The best way to find it is to look for the kafka.log path (above). conduktor.log sits at the same place