Unable to run Clouseau after following the documentation

[natcohen]

Description

Unable to run Clouseau even after following the installation procedure.

Steps to Reproduce

After carefully following the procedure here I'm unable to get it working on CentOS 8. Here is what I have done:

• Installed Java 8 as described here.

• Unzipped the Clouseau release in folder /opt/clouseau and added the clouseau.ini
log4j.properties files (as described in the procedure) in the same folder.

• Added the classpath:

    export CLASSPATH=/opt/clouseau/*`

• Tried to run it with the following command:

    java -server \
         -Xmx2G \
         -Dsun.net.inetaddr.ttl=30 \
         -Dsun.net.inetaddr.negative.ttl=30 \
         -Dlog4j.configuration=file:/opt/clouseau/log4j.properties \
         -XX:OnOutOfMemoryError=\"kill -9 %p\" \
         -XX:+UseConcMarkSweepGC \
         -XX:+CMSParallelRemarkEnabled \
         com.cloudant.clouseau.Main \
         /opt/clouseau/clouseau.ini

But I'm getting the following error:

Unrecognized option: -9
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.

In addition, I can see in the default.ini file of CouchDB some reference to dreyfus. Does it mean that I should add a configuration to CouchDB?

Also

cookie=monster

is described as "; set this to the same distributed Erlang cookie used by the CouchDB nodes" but I don't know where to find that.

Expected Behaviour

The Clouseau configuration should be easier to setup (probably by improving the documentation)

Your Environment

• CouchDB version used: 3.0
• Browser name and version: N/A
• Operating system and version: CentOS 8

Additional Context

[kocolosk]

Hi @natcohen, thanks for the report.

The distributed Erlang cookie can be set a few different ways. The etc/vm.args file has a line that starts with -setcookie; this is probably the one that's in effect. It defaults to the same monster value above.

The -9 error looks like a problem with quoting in the shell. I'll confess that I tend to get that sort of thing working by trial and error 🙄 As a test you could remove the entire line:

     -XX:OnOutOfMemoryError=\"kill -9 %p\" \

and see if that gets you going.

[natcohen]

@kocolosk Great, without this line, it seems to work (I will do some tests).

BTW, should we remove this line from the documentation? Also should we explain where this setcookie value is taken from?

In addition, once I run clouseau, do I have to restart CouchDB? Do I have to do anything within CouchDB (from the fresh install)?

[natcohen]

It also works without escaping the scopes:

-XX:OnOutOfMemoryError="kill -9 %p" \

[kocolosk]

You shouldn't need to restart CouchDB, any request that needs a Clouseau process will try to establish a connection to it if one does not already exist.

I do think we could improve the documentation based on your experience, especially the bit about the Erlang magic cookie. I'm not sure about removing the kill -9 direction altogether; it has been our recommended practice to set that flag to help the system quickly recover from any condition that could cause the JVM memory to balloon.

It'd be nice if we could find a way to make that easier to invoke, e.g. by including a script that starts / stops the Clouseau service. But I'm not sure anyone is ready to pick that up. Will need to give it some thought.

[natcohen]

@kocolosk Thanks for your help!

Does it mean that escaping with backslashes depends on the server/OS? This could definitely be added to the documentation if we can determine which OS require escaping

[natcohen]

I will close this since it's not a real bug but more a documentation issue...