Raffi Basmajian created KARAF-4073:
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Summary: Very high cpu caused by executing commands using
shell:exec
Key: KARAF-4073
URL: https://issues.apache.org/jira/browse/KARAF-4073
Project: Karaf
Issue Type: Bug
Components: karaf-shell
Affects Versions: 2.4.3
Environment: Client - Windows 7 SP1
Server - Ubuntu 15.04
Reporter: Raffi Basmajian
Priority: Minor
Currently building AMQ messaging platform across multiple data centers using
standalone AMQ brokers on Jboss Fuse 6.2/Karaf 2.4. We needed a tool for
automating diagnostic and configuration commands across many servers with a
single command (we're not using Fabric). So we started playing with Karaf's
console commands. Most commands work as advertised, except for shell:exec,
which appears to cause very high cpu consumption in certain instances; the
issue is fairly easy to reproduce.
On Ubuntu 15.04/Java 1.8.0_45-b14
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1) Install JBoss Fuse 6.2 (133)
http://www.jboss.org/download-manager/file/jboss-fuse-6.2.0.GA-full_zip.zip
2) Extract, then start using bin/fuse
3) Start local or remote console session
4) Execute any of these, keep eye on cpu usage
{quote}
shell:exec ls
shell:exec id
shell:exec df -h
{quote}
While cpu was pegged at 99%, we observed what appeared to be high context
switching activity in the following threads, which we assume to be threads for
streaming command output. I've attached a stack trace showing these threads.
Input Pump for Commans[ls]
Error pump for Command[ls]
Since we observed the issue on Jboss Fuse 6.2, which uses Karaf 2.4, I
downloaded and started a standalone instance of Karaf 2.4.3. Using the same
steps above, I reproduced the issue on my first attempt, so it appears this
issue is rooted with something in Karaf, not Fuse.
I also reproduced the issue on RHEL 7.1/Java 1.8 (same as above), on both
Fuse/Karaf 2.4 and standalone Karaf 2.4.3.
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