update gcsfuse logging guide (#1538)

docs/logging.md

@@ -1,81 +1,5 @@
 # GCSFuse User Logging Guide
-This readme describes about the logging support in gcsfuse and how users can use
-that support.
-
-GCSFuse supports different debug flags e.g. --debug_fs, --debug_fuse, 
---debug_gcs etc. Each of these flags logs debug info of a different component
-of gcsfuse. For more information, use `gcsfuse --help`.
-
-## Log location
-GCSFuse logs its activity to a file if the user specifies one with the `--log-file`
-flag. Otherwise, it logs to **stdout** in the foreground and to **syslog** in the background.
-
-## Log rotation
-GCSFuse does not automatically rotate logs, so you must configure this manually.
-
-### To support the rotation of logs written to syslog
-1. Please make sure you have `rsyslog`, `logrotate` and `cron` packages installed
-and running on the system.
-E.g. commands to install and run the packages on Ubuntu/Debian:
-```bash
-sudo add-apt-repository ppa:adiscon/v8-devel
-sudo apt-get update
-sudo apt-get install rsyslog logrotate cron
-
-sudo systemctl start rsyslog
-sudo systemctl start logrotate
-sudo systemctl start cron
-```
-2. Run the shell script located at [this](https://github.com/GoogleCloudPlatform/gcsfuse/blob/master/tools/log_rotate/install_script.sh) location.
-It installs the configuration for rsyslog (to redirect gcsfuse logs from
-syslog to `/var/log/gcsfuse.log`), logrotate and cron. In the end, restart the
-syslog service.
-3. Mount the GCS bucket using GCSFuse command with logs enabled in background mode.
-Also, verify the logs present at `/var/log/gcsfuse.log`.
-4. Run the below command to test this setup.
-```bash
-# The below command should run successfully, it will trigger the hourly cron job.
-# Cron will trigger logrotate and you will find the logrotate status in
-# /var/log/logrotate/status file.
-sudo run-parts -v /etc/cron.hourly 
-```
-
-### To support the rotation of logs written to custom log-file
-E.g. assume you pass `--log-file=/$HOME/test.log`, gcsfuse will start writing
-the logs to `/$HOME/test.log`. Now, to support log rotation, you can follow the
-below steps:
-
-1. Create a logrotate configuration file (gcsfuse-custom-logrotate-conf):
-```bash
-/$HOME/test.log {
-    rotate 10
-    size 5G
-    missingok
-    notifempty
-    compress
-    dateext
-    dateformat -%Y%m%d-%s
-    copytruncate
-}
-```
-
-Here,
-``` text
-* rotate 10 - means only 10 backup files will be kept other than original file.
-* size 5G - rotation will take place only when file size exceeds this.
-* missingok - if a log file is missing, logrotate will not issue an error.
-* notifempty - do not rotate the log if log files are empty.
-* compress - old versions of log files are compressed with gzip by default.
-* dateext - archive logs with date extension instead of adding a number.
-* dateformat %Y%m%d-%s - added %s to make a unique rotate-log file name in hourly cron setup.
-* copytruncate - truncate the original log file in place after creating a copy, instead 
-of moving the old log file and optionally creating a new one.
-```
-2. You can verify the above created config using this logrotate command:
-   `/usr/sbin/logrotate -d <config_file_path>`
-3. Create a cron job which will execute the logrotate command periodically. E.g.
-the below command creates a cron job which runs every 2 minutes. 
-`echo "*/2 * * * * /usr/sbin/logrotate <abs_path_to_config_file> --state <abs_path_to_state_file>" | crontab _`  
-Note: `--state` flag is useful if logrotate is being run as different user, it saves
-status of logrotate execution as we get by default in `/var/lib/logrotate/status`.
 
+For instructions on how to enable Cloud Storage FUSE logs, refer to
+the `logging` configurations outlined in the gcsfuse configuration
+file https://cloud.google.com/storage/docs/gcsfuse-config-file.