.. _acrnlog:
acrnlog
#######
Description
***********
``acrnlog`` is a userland tool used to capture a ACRN hypervisor log. It runs as an
SOS service at boot, capturing two kinds of logs:
- log of the currently running hypervisor
- log of last running hypervisor if it crashed and the logs remain.
Log files are saved in ``/tmp/acrnlog/``, so the log files would be lost
after a system reset.
Usage
*****
The ``acrnlog`` tool is launched as a service at boot, and limited to
supporting four 1MB log files by default. You can change this log file
limitation temporarily or permanently.
Options:
-h display help
-t specify a polling interval (ms). Once buffer is empty, acrnlog stops
and starts reading in specified interval.
If an incomplete log warning is reported, please try with a smaller
interval to get a complete log.
-s limit the size of each log file, in KB. 0 means no limitation.
-n specify the number of log files to keep, old files would be deleted.
Temporary log file changes
==========================
You can temporarily change the log file setting by following these
steps:
1. Stop the ``acrnlog`` service:
.. code-block:: none
# systemctl disable acrnlog
2. Restart ``acrnlog``, running in the background, and specify the new
number of log files and their size (in MB). For example:
.. code-block:: none
# acrnlog -n 8 -s 4 &
You can use ``loglevel`` command in the hypervisor shell (not the Service
OS shell) to query and change the hypervisor log level.
The ``mem_loglevel`` parameter controls the log to be saved using
``acrnlog``, while the ``console_loglevel`` parameter controls the log
output to the console. For example, in the hypervisor shell you
can use these commands:
.. code-block:: none
ACRN:\>loglevel
console_loglevel: 3, mem_loglevel: 5, npk_loglevel: 5
ACRN:\>loglevel 2 5
ACRN:\>loglevel
console_loglevel: 2, mem_loglevel: 5, npk_loglevel: 5
Permanent log file changes
==========================
You can also permanently change the log file settings by
editing ``/usr/lib/systemd/system/acrnlog.service`` and use the ``-n``
and ``-s`` options on the ``ExecStart`` cmd, and restart the service.
For example, ``acrnlog.service`` could have these parameters added:
.. code-block:: none
ExecStart=/usr/bin/acrnlog -n 8 -s 4
and then restart the service with:
.. code-block:: none
# systemctl daemon-reload
# systemctl restart acrnlog
Build and Install
*****************
Source code for the ``acrnlog`` tools is in the ``tools/acrnlog``
folder. Build and install the tools from source using:
.. code-block:: none
# make
# make install
and if you changed the ``acrnlog.service`` file, install it using:
.. code-block:: none
# cp acrnlog.service /usr/lib/systemd/system/
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