# Filebeat locks application logs on Windows

(cisconetgineer) #1

Hi,

I am testing filebeat and it locks application files on Windows 2008.
I tried version 1.23, 5.0.0 alpha4 and 5.0.0 apha5.
All of them exhibits the same issue.

Here are stepsI tested.

1. start filebeat, start application, appears to work fine

2. kill application, start application, application complains it cannot write to log file

3. kill filebeat, application can write to log file again

4. start filebeat. Application cannot write to log file anymore

error message
Unable to access or create the log file. 'Encounted a sharing violation while accessing C:\Prinelog\prime_HSSYTEM.log' The application will now shut down.

I'd like to add the filebeat config is very simple.

filebeat.prospectors:

# Each - is a prospector. Most options can be set at the prospector level, so
# you can use different prospectors for various configurations.
# Below are the prospector specific configurations.

- input_type: log

# Paths that should be crawled and fetched. Glob based paths.
paths:
- C:\Primelog\prime_HSSYSTEM.log
#- c:\programdata\elasticsearch\logs\*

# Exclude lines. A list of regular expressions to match. It drops the lines that are
# matching any regular expression from the list.
#exclude_lines: ["^DBG"]

# Include lines. A list of regular expressions to match. It exports the lines that are
# matching any regular expression from the list.
#include_lines: ["^ERR", "^WARN"]

# Exclude files. A list of regular expressions to match. Filebeat drops the files that
# are matching any regular expression from the list. By default, no files are dropped.
#exclude_files: [".gz\$"]

# Optional additional fields. These field can be freely picked
# to add additional information to the crawled log files for filtering
#fields:
#  level: debug
#  review: 1

### Multiline options

# Mutiline can be used for log messages spanning multiple lines. This is common
# for Java Stack Traces or C-Line Continuation

# The regexp Pattern that has to be matched. The example pattern matches all lines starting with [
#multiline.pattern: ^\[

# Defines if the pattern set under pattern should be negated or not. Default is false.
#multiline.negate: false

# Match can be set to "after" or "before". It is used to define if lines should be append to a pattern
# that was (not) matched before or after or as long as a pattern is not matched based on negate.
# Note: After is the equivalent to previous and before is the equivalent to to next in Logstash
#multiline.match: after

#================================ General =====================================

# The name of the shipper that publishes the network data. It can be used to group
# all the transactions sent by a single shipper in the web interface.
#name:

# The tags of the shipper are included in their own field with each
# transaction published.
#tags: ["service-X", "web-tier"]

# Optional fields that you can specify to add additional information to the
# output.
#fields:
#  env: staging

#================================ Outputs =====================================

# Configure what outputs to use when sending the data collected by the beat.
# Multiple outputs may be used.

#-------------------------- Elasticsearch output ------------------------------
output.elasticsearch:
# Array of hosts to connect to.
hosts: ["hst-py-util-01:9200"]

# Optional protocol and basic auth credentials.
#protocol: "https"


thanks,

(Andrew Kroh) #2

Filebeat does not lock the log files that it reads from. On Windows, Filebeat requests only generic read access to the file. It uses the share mode bit mask of FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE which can allow other applications to read/write/delete the file.

It's most likely that the application is requesting exclusive rights to the file (an empty share mode bit mask). If this is the case, Windows will prevent the application from opening the file when another application has any handle open to the file (event just for reading). Windows gives a ERROR_SHARING_VIOLATION in this case.

To determine the share mode bits used by your application, start the application, and then use the Sysinternals handle.exe tool to see what share mode bits are set for the log file handle. For an example see this post: File open mode

Reference: CreateFile function

Filebeat docker running on windows not allowing application to rotate the log!
(cisconetgineer) #3

Handle.exe shows the log directory C:\Primelog mode is
D24: File (RWD) C:\Primelog

Does this mean it's exclusive?

(Andrew Kroh) #4

Based on my understanding of that tool, I think that means your application is using the same share mask as Filebeat so maybe that isn't the issue. Can you list the handles for Filebeat too and paste the output. Thanks

(cisconetgineer) #5

Here is handle output for filebeat
DCC: File (RWD) C:\filebeat\filebeat-5.0.0-alpha5-SNAPSHOT-windows-x86_64

(cisconetgineer) #6

This is the handle from filebeat to the log file

filebeat.exe pid: 14312 NT AUTHORITY\SYSTEM
C: File (RW-) C:\Windows\System32
258: File (RWD) C:\Primelog\prime_HSSYSTEM.log

(Andrew Kroh) #7

Shouldn't there be a handle listing for "C:\Primelog\prime_HSSYSTEM.log" coming from your application?

(cisconetgineer) #8

It appears this application will not allow any open handles from other apps(e.g. tail, filebeat) on startup. Thanks for your help.

(system) #9

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