Bug 1707176

Summary: JOURNAL_READ_FROM_HEAD defaults to true
Product: OpenShift Container Platform Reporter: Rich Megginson <rmeggins>
Component: LoggingAssignee: Jeff Cantrill <jcantril>
Status: CLOSED ERRATA QA Contact: Anping Li <anli>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: aos-bugs, pweil, rmeggins
Target Milestone: ---   
Target Release: 4.1.0   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Cause: The environment variable JOURNAL_READ_FROM_HEAD is set to the empty string. This causes the default value of read_from_head for the journald input to be true. When Fluentd starts up for the first time on a node, it reads in the entire journal. Consequence: It may take hours for system messages to show up in Elasticsearch and Kibana. Fix: Fluentd will check if the value is set _and_ is not empty, otherwise, it will use a default of false. Result: Fluentd will read from the tail of the journal when it starts up on a new node.
Story Points: ---
Clone Of:
: 1707524 (view as bug list) Environment:
Last Closed: 2019-06-04 10:48:31 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 1707524, 1707556, 1707557    

Description Rich Megginson 2019-05-07 00:59:13 UTC
Description of problem:

The default value for JOURNAL_READ_FROM_HEAD is true, meaning that when fluentd starts up, it tries to read in the entire journald by default.

The reason is that the cluster-logging-operator sets the env. var. JOURNAL_READ_FROM_HEAD to the empty string "".
Fluentd has this code:

     read_from_head "#{ENV['JOURNAL_READ_FROM_HEAD'] || 'false'}"

which then evaluates to 

     read_from_head

since read_from_head is a boolean parameter, this tells Fluentd to set the value to true, which is the opposite of the intention.

Version-Release number of selected component (if applicable):


How reproducible:


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Expected results:


Additional info:
https://github.com/openshift/origin-aggregated-logging/pull/1630

Comment 3 Anping Li 2019-05-08 04:55:48 UTC
Verified and pass using openshift/ose-logging-fluentd:v4.1.0-201905070632

Comment 5 errata-xmlrpc 2019-06-04 10:48:31 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2019:0758