Logwatch
①Install
| 1 | # dnf install logwatch | 
②Edit configuration file
| 1 2 3 4 5 6 7 8 9 | # cat /usr/share/logwatch/default.conf/logwatch.conf >> /etc/logwatch/conf/logwatch.conf # vi /etc/logwatch/conf/logwatch.conf ●Line 53 : Set "MailTo = root" as a comment and set the email address you want to receive notifications to the line below it. #MailTo = root MailTo = [Mail address] ●Per line 86 : Set the level of detail for log notifications #Detail = Low Detail = High | 
③Output Logwatch reports
| 1 | # logwatch --output stdout | 
It will appear as follows
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 |  ################### Logwatch 7.9 (07/22/23) ####################         Processing Initiated: Mon Nov 13 13:08:59 2023         Date Range Processed: yesterday                               ( 2023-Nov-12 )                               Period is day.         Detail Level of Output: 10         Type of Output/Format: stdout / text         Logfiles for Host: Lepard  ##################################################################  --------------------- Kernel Audit Begin ------------------------  *** Denials ***     system_u:system_r:init_t:s0 system_u:object_r:root_t:s0 (rmdir dir): 2 times     system_u:system_r:systemd_hwdb_t:s0 system_u:system_r:systemd_hwdb_t:s0 (dac_override capability): 1 times   Number of audit daemon starts: 3   Number of audit daemon stops: 3   Number of audit initializations: 3 -----------omission--------- **Unmatched Entries**     No hostname configured, using default hostname.: 2 Time(s)     Reexecuting requested from client PID 2099 ('systemctl') (unit session-5.scope)...: 1 Time(s)     Relabeled /dev, /dev/shm, /run, /sys/fs/cgroup in 26.739ms.: 1 Time(s)     Reloading...: 15 Time(s)     Running in initrd.: 3 Time(s)  ---------------------- Systemd End -------------------------  --------------------- Disk Space Begin ------------------------  Filesystem               Size  Used Avail Use% Mounted on  /dev/mapper/fedora-root   15G  4.3G   11G  29% /  /dev/nvme0n1p2           960M  286M  675M  30% /boot  ---------------------- Disk Space End -------------------------  ###################### Logwatch End ######################### | 
④Test to see if the report arrives at the address you set. Check if you receive a log report email like the one above.
| 1 | # /etc/cron.daily/0logwatch | 
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Introduce disk usage check script
1 Script Creation
| 1 2 | # cd /var/www/system # vi disk_capacity_check.sh | 
Contents of disk_capacity_check.sh
| 1 2 3 4 5 6 7 8 9 10 | #!/bin/bash #Designation of e-mail address to be notified MAIL="<Mail address>" DVAL=`/bin/df / | /usr/bin/tail -1 | /bin/sed 's/^.* \([0-9]*\)%.*$/\1/'` if [ $DVAL -gt 80 ]; then echo "Disk usage alert: $DVAL %" | mail -s "Disk Space Alert in `hostname`" $MAIL fi | 
| 1 | # chmod 700 disk_capacity_check.sh | 
2 Execution Confirmation
①Check current usage rates
| 1 | # df -h | 
It appears as follows
| 1 2 3 4 5 6 7 8 | Filesystem               Size  Used Avail Use% Mounted on /dev/mapper/fedora-root   15G  4.3G   11G  29% / devtmpfs                 4.0M     0  4.0M   0% /dev tmpfs                    2.9G     0  2.9G   0% /dev/shm tmpfs                    1.2G  1.6M  1.2G   1% /run tmpfs                    2.9G     0  2.9G   0% /tmp /dev/nvme0n1p2           960M  286M  675M  30% /boot tmpfs                    594M  4.0K  594M   1% /run/user/1000 | 
②Create a dummy file to achieve at least 80% utilization(In the example, the name is dummyfile and it is about 10G.)
| 1 | # dd if=/dev/zero of=dummyfile bs=1M count=10000 | 
➂Run check scripts
| 1 | # /var/www/system/disk_capacity_check.sh | 
You will receive an email to the email address you have set up, stating something like "Disk usage alert: 94%".
④Delete "dummyfile"
| 1 | # rm dummyfile | 
⑤Periodic Execution Setting
| 1 2 | # crontab -e 30 2 * * * /var/www/system/disk_capacity_check.sh | 
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