Contents
Tripwire
1.インストール
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# dnf -y install tripwire Installed: tripwire-2.4.3.7-16.el9.x86_64 Complete! |
2.パスフレーズ設定
サイトパスフレーズとローカルパスフレーズを設定する
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# tripwire-setup-keyfiles |
------------------------------------------------
The Tripwire site and local passphrases are used to sign a variety of
files, such as the configuration, policy, and database files.
Passphrases should be at least 8 characters in length and contain both
letters and numbers.
See the Tripwire manual for more information.
------------------------------------------------
Creating key files…
(When selecting a passphrase, keep in mind that good passphrases typically
have upper and lower case letters, digits and punctuation marks, and are
at least 8 characters in length.)
Enter the site keyfile passphrase: [site pass]
Verify the site keyfile passphrase: [site pass]
Generating key (this may take several minutes)…Key generation complete.
(When selecting a passphrase, keep in mind that good passphrases typically
have upper and lower case letters, digits and punctuation marks, and are
at least 8 characters in length.)
Enter the local keyfile passphrase: [local pass]
Verify the local keyfile passphrase: [local pass]
Generating key (this may take several minutes)…Key generation complete.
------------------------------------------------
Signing configuration file…
Please enter your site passphrase: [site pass]
Wrote configuration file: /etc/tripwire/tw.cfg
A clear-text version of the Tripwire configuration file:
/etc/tripwire/twcfg.txt
has been preserved for your inspection. It is recommended that you
move this file to a secure location and/or encrypt it in place (using a
tool such as GPG, for example) after you have examined it.
------------------------------------------------
Signing policy file…
Please enter your site passphrase: [site pass]
Wrote policy file: /etc/tripwire/tw.pol
A clear-text version of the Tripwire policy file:
/etc/tripwire/twpol.txt
has been preserved for your inspection. This implements a minimal
policy, intended only to test essential Tripwire functionality. You
should edit the policy file to describe your system, and then use
twadmin to generate a new signed copy of the Tripwire policy.
Once you have a satisfactory Tripwire policy file, you should move the
clear-text version to a secure location and/or encrypt it in place
(using a tool such as GPG, for example).
Now run "tripwire --init" to enter Database Initialization Mode. This
reads the policy file, generates a database based on its contents, and
then cryptographically signs the resulting database. Options can be
entered on the command line to specify which policy, configuration, and
key files are used to create the database. The filename for the
database can be specified as well. If no options are specified, the
default values from the current configuration file are used.
3.Tripwire の設定
①設定ファイル編集
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# vi /etc/tripwire/twcfg.txt 9 行目 「LOOSEDIRECTORYCHECKING =true」に変更 12 行目変更 レベル4 にすることで「0 」～「4 」までの5 段階中、最も詳細なレポートが表示されます。 REPORTLEVEL =4 |
②Tripwire 設定ファイル(暗号署名版)を作成
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# twadmin -m F -c /etc/tripwire/tw.cfg -S /etc/tripwire/site.key /etc/tripwire/twcfg.txt Please enter your site passphrase: ←site pass Wrote configuration file: /etc/tripwire/tw.cfg |
③Tripwire 設定ファイル(テキスト版)削除
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# rm -f /etc/tripwire/twcfg.txt |
④ポリシーファイル設定
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# cd /etc/tripwire/ # vi twpolmake.pl |
twpolmake.plの内容
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#!/usr/bin/perl # $POLFILE=$ARGV[0]; open(POL,"$POLFILE") or die "open error: $POLFILE" ; my($myhost,$thost) ; my($sharp,$tpath,$cond) ; my($INRULE) = 0 ; while (<POL>) { chomp; if (($thost) = /^HOSTNAME\s*=\s*(.*)\s*;/) { $myhost = `hostname` ; chomp($myhost) ; if ($thost ne $myhost) { $_="HOSTNAME=\"$myhost\";" ; } } elsif ( /^{/ ) { $INRULE=1 ; } elsif ( /^}/ ) { $INRULE=0 ; } elsif ($INRULE == 1 and ($sharp,$tpath,$cond) = /^(\s*\#?\s*)(\/\S+)\b(\s+->\s+.+)$/) { $ret = ($sharp =~ s/\#//g) ; if ($tpath eq '/sbin/e2fsadm' ) { $cond =~ s/;\s+(tune2fs.*)$/; \#$1/ ; } if (! -s $tpath) { $_ = "$sharp#$tpath$cond" if ($ret == 0) ; } else { $_ = "$sharp$tpath$cond" ; } } print "$_\n" ; } close(POL) ; |
⑤ポリシーファイル最適化
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# perl /etc/tripwire/twpolmake.pl /etc/tripwire/twpol.txt > /etc/tripwire/twpol.txt.new |
⑥最適化済ポリシーファイルを元に、ポリシーファイル(暗号署名版)作成
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# twadmin -m P -c /etc/tripwire/tw.cfg -p /etc/tripwire/tw.pol -S /etc/tripwire/site.key /etc/tripwire/twpol.txt.new Please enter your site passphrase: ←site pass Wrote policy file: /etc/tripwire/tw.pol |
⑦データベースを作成、動作確認
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# tripwire -m i -s -c /etc/tripwire/tw.cfg Please enter your local passphrase: ←local pass |
テスト用ファイルを作成
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# echo test > /root/test.txt |
Tripwire の動作確認
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# tripwire -m c -s -c /etc/tripwire/tw.cfg 下記のように表示されればOK Open Source Tripwire(R) 2.4.3.7 Integrity Check Report Report generated by: root Report created on: Sun 28 Dec 2025 01:45:58 PM JST Database last updated on: Never =============================================================================== Report Summary: =============================================================================== Host name: Lepard Host IP address: 192.168.11.83 Host ID: None Policy file used: /etc/tripwire/tw.pol Configuration file used: /etc/tripwire/tw.cfg Database file used: /var/lib/tripwire/Lepard.twd Command line used: tripwire -m c -s -c /etc/tripwire/tw.cfg =============================================================================== Rule Summary: =============================================================================== ------------------------------------------------------------------------------- Section: Unix File System ------------------------------------------------------------------------------- Rule Name Severity Level Added Removed Modified --------- -------------- ----- ------- -------- User binaries 66 0 0 0 Tripwire Binaries 100 0 0 0 Libraries 66 0 0 0 Operating System Utilities 100 0 0 0 File System and Disk Administraton Programs 100 0 0 0 Kernel Administration Programs 100 0 0 0 Networking Programs 100 0 0 0 System Administration Programs 100 0 0 0 Hardware and Device Control Programs 100 0 0 0 System Information Programs 100 0 0 0 (/sbin/runlevel) Application Information Programs 100 0 0 0 (/sbin/rtmon) Critical Utility Sym-Links 100 0 0 0 Shell Binaries 100 0 0 0 Critical system boot files 100 0 0 0 * Tripwire Data Files 100 1 0 0 System boot changes 100 0 0 0 OS executables and libraries 100 0 0 0 Security Control 100 0 0 0 Login Scripts 100 0 0 0 Critical configuration files 100 0 0 0 * Root config files 100 1 0 0 Invariant Directories 66 0 0 0 Temporary directories 33 0 0 0 Critical devices 100 0 0 0 Total objects scanned: 67033 Total violations found: 2 =============================================================================== Object Summary: =============================================================================== ------------------------------------------------------------------------------- # Section: Unix File System ------------------------------------------------------------------------------- ------------------------------------------------------------------------------- Rule Name: Tripwire Data Files (/var/lib/tripwire) Severity Level: 100 ------------------------------------------------------------------------------- Added: "/var/lib/tripwire/Lepard.twd" ------------------------------------------------------------------------------- Rule Name: Root config files (/root) Severity Level: 100 ------------------------------------------------------------------------------- Added: "/root/test.txt" =============================================================================== Error Report: =============================================================================== No Errors ------------------------------------------------------------------------------- *** End of report *** Open Source Tripwire 2.4 Portions copyright 2000-2018 Tripwire, Inc. Tripwire is a registered trademark of Tripwire, Inc. This software comes with ABSOLUTELY NO WARRANTY; for details use --version. This is free software which may be redistributed or modified only under certain conditions; see COPYING for details. All rights reserved. |
テスト用ファイルを削除
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# rm -f /root/test.txt |
⑧Tripwire メールで結果報告用スクリプト作成
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# cd /var/www/system # vi tripwire.sh |
#!/bin/bash
PATH=/usr/sbin:/usr/bin:/bin:/usr/local/tripwire/sbin
#パスフレーズ設定
LOCALPASS=xxxxx # local pass
SITEPASS=xxxxx # site pass
#通知先メールアドレス指定
MAIL="[your mail address] "
cd /etc/tripwire
#Tripwireチェック実行
tripwire -m c -s -c tw.cfg|mail -s "Tripwire(R) Integrity Check Report in `hostname`" $MAIL
#ポリシーファイル最新化
twadmin -m p -c tw.cfg -p tw.pol -S site.key > twpol.txt
perl twpolmake.pl twpol.txt > twpol.txt.new
twadmin -m P -c tw.cfg -p tw.pol -S site.key -Q $SITEPASS twpol.txt.new > /dev/null
rm -f twpol.txt* *.bak
#データベース最新化
rm -f /usr/local/tripwire/lib/tripwire/*.twd*
tripwire -m i -s -c tw.cfg -P $LOCALPASS
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# chmod 700 tripwire.sh cron に追加 # crontab -e 0 3 * * * /var/www/system/tripwire.sh |
下記コマンドを実行し、指定したメールアドレスにtripwire実行結果が通知されることを確認
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# /var/www/system/tripwire.sh |
Chkrootkit
chkrootkitというrootkit検知ツールを導入して、rootkitがLinuxサーバーにインストールされてしまっていないかチェックする。
chkrootkitは、以下のコマンドを使用してチェックするため、コマンド自体がrootkitを検知できないように改竄されてからでは意味がないので、Linuxインストール後の初期の段階で導入しておくのが望ましい。
【chkrootkitが使用するコマンド】
awk, cut, echo, egrep, find, head, id, ls, netstat, ps, strings, sed, uname
なお、chkrootkitが検知できるのは既知のrootkitのみであり、新たなrootkitの検知はできない。
①chkrootkit をダウンロード、インストール
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# cd /usr/local/src # wget https://launchpad.net/chkrootkit/main/0.55/+download/chkrootkit-0.55.tar.gz # tar xvf chkrootkit-0.55.tar.gz |
➁/root/bin ディレクトリを作成し、そのディレクトリにchkrootkit コマンドを移動
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# mkdir -p /root/bin # mv chkrootkit-0.55/chkrootkit /root/bin |
➂chkrootkit を確認
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# chkrootkit | grep INFECTED 何も表示されなければ問題ありません |
④chkrootkit 定期実行スクリプトの作成と権限変更
chkrootkit実行スクリプトを毎日自動実行されるディレクトリへ作成
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# vi /etc/cron.daily/chkrootkit |
定期実行スクリプトの内容
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#!/bin/bash PATH=/usr/bin:/bin:/root/bin LOG=/tmp/$(basename ${0}) # chkrootkit実行 chkrootkit > $LOG 2>&1 # ログ出力 cat $LOG | logger -t $(basename ${0}) # SMTPSのbindshell誤検知対応 if [ ! -z "$(grep 465 $LOG)" ] && \ [ -z $(/usr/sbin/lsof -i:465|grep bindshell) ]; then sed -i '/465/d' $LOG fi # upstartパッケージ更新時のSuckit誤検知対応 if [ ! -z "$(grep Suckit $LOG)" ] && \ [ -z "$(rpm -V `rpm -qf /sbin/init`)" ]; then sed -i '/Suckit/d' $LOG fi # rootkit検知時のみroot宛メール送信 [ ! -z "$(grep INFECTED $LOG)" ] && \ grep INFECTED $LOG | mail -s "chkrootkit report in `hostname`" root |
chkrootkit実行スクリプトへ実行権限付加
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# chmod 700 /etc/cron.daily/chkrootkit |
⑤chkrootkit が使用するコマンドをバックアップ
chkrootkit が使用するコマンドが改ざんされた場合、rootkit を検出できなくなるので、
これらのコマンドをバックアップしておきます。
必要な場合は、バックアップしたコマンドを使用してchkrootkit を実行します
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# cd /root # mkdir /root/chkrootkit_cmd # cp `which --skip-alias awk cut echo egrep find head id ls netstat ps strings sed ssh uname` chkrootkit_cmd/ # ls -l /root/chkrootkit_cmd/ total 2628 -rwxr-xr-x 1 root root 714968 Dec 28 14:09 awk -rwxr-xr-x 1 root root 48760 Dec 28 14:09 cut -rwxr-xr-x 1 root root 36136 Dec 28 14:09 echo -rwxr-xr-x 1 root root 32 Dec 28 14:09 egrep -rwxr-xr-x 1 root root 291800 Dec 28 14:09 find -rwxr-xr-x 1 root root 44656 Dec 28 14:09 head -rwxr-xr-x 1 root root 40472 Dec 28 14:09 id -rwxr-xr-x 1 root root 140752 Dec 28 14:09 ls -rwxr-xr-x 1 root root 160608 Dec 28 14:09 netstat -rwxr-xr-x 1 root root 144536 Dec 28 14:09 ps -rwxr-xr-x 1 root root 116736 Dec 28 14:09 sed -rwxr-xr-x 1 root root 863632 Dec 28 14:09 ssh -rwxr-xr-x 1 root root 32504 Dec 28 14:09 strings -rwxr-xr-x 1 root root 32232 Dec 28 14:09 uname |
⑥コピーしたコマンドにchkrootkit を実行
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# chkrootkit -p /root/chkrootkit_cmd | grep INFECTED |
何も表示されなければ問題ありません
⑦バックアップしたコマンドを圧縮
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# tar zcvf chkrootkit_cmd.tar.gz chkrootkit_cmd chkrootkit_cmd/ chkrootkit_cmd/awk chkrootkit_cmd/cut chkrootkit_cmd/echo chkrootkit_cmd/egrep chkrootkit_cmd/find chkrootkit_cmd/head chkrootkit_cmd/id chkrootkit_cmd/ls chkrootkit_cmd/netstat chkrootkit_cmd/ps chkrootkit_cmd/strings chkrootkit_cmd/sed chkrootkit_cmd/ssh chkrootkit_cmd/uname |
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# ls -l total 1812 -rw-------. 1 root root 1200 Dec 26 11:36 anaconda-ks.cfg -rw------- 1 root root 473 Dec 28 12:57 appid_stats.log drwxr-xr-x 2 root root 24 Dec 28 14:03 bin drwxr-xr-x 2 root root 172 Dec 28 14:09 chkrootkit_cmd -rw-r--r-- 1 root root 1227188 Dec 28 14:10 chkrootkit_cmd.tar.gz -rw------- 1 root root 5338 Dec 28 13:58 dead.letter drwxr-xr-x 9 root root 4096 Dec 28 09:43 libdaq drwxr-xr-x 4 5001 2010 134 Jun 10 2023 odp -rw-r--r-- 1 root root 599862 Jun 17 2023 OpenAppId-33380.tgz drwx------ 3 root root 21 Dec 27 11:59 snap drwxr-xr-x 10 root root 4096 Dec 28 10:00 snort3 |
⑧chkrootkit使用コマンド(圧縮版)をroot宛にメール送信
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# echo|mail -a chkrootkit_cmd.tar.gz -s chkrootkit_cmd.tar.gz root |
⑨Windows にchkrootkit_cmd.tar.gz ファイルをダウンロードして退避
⑩バックアップしたサーバー上のコマンドを削除
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# rm -f chkrootkit_cmd.tar.gz |
Logwatch
①インストール
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# dnf -y install logwatch |
②設定ファイルの編集
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# cat /usr/share/logwatch/default.conf/logwatch.conf >> /etc/logwatch/conf/logwatch.conf # vi /etc/logwatch/conf/logwatch.conf 51 行目 : コメント #MailTo = root 52行目 : 追加 MailTo = [メールアドレス] 84行目あたりログ通知の詳細度を設定 #Detail = Low Detail = High |
③Logwatch のレポートを出力
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# logwatch --output stdout |
下記のようなメッセージが出ます
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################### Logwatch 7.5.5 (01/22/21) #################### Processing Initiated: Sun Dec 28 14:16:01 2025 Date Range Processed: yesterday ( 2025-Dec-27 ) Period is day. Detail Level of Output: 10 Type of Output/Format: stdout / text Logfiles for Host: Lepard --------------------- Clamav Begin ------------------------ Daemon check list: Database status OK: 59 Time(s) ---------------------- Clamav End ------------------------- --------------------- Clamav-milter Begin ------------------------ --------------------------------- --------------------------------- --------------------- Disk Space Begin ------------------------ Filesystem Size Used Avail Use% Mounted on /dev/mapper/rl-root 17G 8.5G 8.6G 50% / /dev/nvme0n1p1 960M 395M 566M 42% /boot ---------------------- Disk Space End ------------------------- --------------------- lm_sensors output Begin ------------------------ No sensors found! Make sure you loaded all the kernel drivers you need. Try sensors-detect to find out which these are. ---------------------- lm_sensors output End ------------------------- ###################### Logwatch End ######################### |
④設定したアドレスにレポートが届くかテストを行います。上記の様なログレポートメールが届いているか確認
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# /etc/cron.daily/0logwatch |
DNS更新
ネットが切断されたり、ルーターが切断再起動したときにおこるグローバルIPの変更の度に、ダイナミックDNSにアクセスしグローバルIPが変更されたことを知らせなくてはいけません。
専用のpythonファイルを作成しCronで定期実行します
今回はValudomainでのDNS設定です
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# cd /var/www/system # vi ddnsset.py |
ddnsset.pyの内容
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#setddns.py import requests import ipaddress from datetime import datetime from pathlib import Path # SETTING DATA MY_DOMAIN = "example.jp" ←自ドメイン MY_PASS = "xxxxxxxxxx" ←パスワード MY_HOSTNAME = "xxxx" ←ホスト名 OUT_FILE = Path("/tmp/ipadress") ←IPアドレス記録ファイル def time_msg(): now = datetime.now() return now.strftime("%Y/%m/%d %H:%M:%S") def is_valid_ip(ip_str): try: ipaddress.ip_address(ip_str) return True except ValueError: return False def main(): # Check Global IP Address url_get_ip = "https://dyn.value-domain.com/cgi-bin/dyn.fcg?ip" try: response = requests.get(url_get_ip, timeout=10) response.raise_for_status() current_ip = response.text.strip() except requests.RequestException as e: print(f"{time_msg()} Failed to get IP: {e}") return # IP check mssg = time_msg() if not current_ip: print(f"{mssg} invalid IP NULL") return if not is_valid_ip(current_ip): print(f"{mssg} invalid IP={current_ip}") return # Read previous IP previous_ip = "" if OUT_FILE.exists(): with open(OUT_FILE, "r") as f: previous_ip = f.read().strip() if current_ip == previous_ip: print(f"{time_msg()} no change IP={current_ip}") return else: print(f"change IP from {previous_ip} to {current_ip}") # Update DDNS mssg = time_msg() print(f"{mssg} access to value-domain") url_set_ddns = ( f"https://dyn.value-domain.com/cgi-bin/dyn.fcg?" f"d={MY_DOMAIN}&p={MY_PASS}&h={MY_HOSTNAME}" ) try: response = requests.get(url_set_ddns, timeout=10) response.raise_for_status() # 改行をスペースに変換し、連続するスペースを1つにまとめる result = ' '.join(response.text.strip().split()) except requests.RequestException as e: print(f"{time_msg()} Failed to update DDNS: {e}") return mssg = time_msg() print(f"{mssg} {MY_HOSTNAME}.{MY_DOMAIN} {result} IP={current_ip}") # DDNS更新が成功した場合のみIPを保存 if "status=0" in result: with open(OUT_FILE, "w") as f: f.write(current_ip) print(f"{mssg} Successfully saved new IP: {current_ip}") else: print(f"{mssg} DDNS update failed, IP not saved") if __name__ == "__main__": main() |
IPアドレス記録ファイル作成
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# touch /tmp/ipadress |
定期的に実行
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# crontab -e * 00 * * * /usr/bin/python3 /var/www/system/ddnsset.py >> /var/log/ddns_updater.log 2>&1 |
ディスク使用率チェックスクリプト
1. スクリプト作成
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# cd /var/www/system # vi disk_capacity_check.sh |
disk_capacity_check.shの内容
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#!/bin/bash #通知先メールアドレス指定 MAIL="<your mailaddress>" 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 |
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# chmod 700 disk_capacity_check.sh |
2. 実行確認
①現在の使用率を確認
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# df -h |
次のように表示される
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Filesystem Size Used Avail Use% Mounted on devtmpfs 4.0M 0 4.0M 0% /dev tmpfs 1.4G 0 1.4G 0% /dev/shm tmpfs 536M 11M 525M 3% /run /dev/mapper/rl-root 17G 8.5G 8.6G 50% / /dev/loop1 128K 128K 0 100% /var/lib/snapd/snap/hello-world/29 /dev/loop0 105M 105M 0 100% /var/lib/snapd/snap/core/17272 /dev/loop2 72M 72M 0 100% /var/lib/snapd/snap/certbot/5234 /dev/loop3 67M 67M 0 100% /var/lib/snapd/snap/core24/1243 /dev/nvme0n1p1 960M 395M 566M 42% /boot /dev/loop4 51M 51M 0 100% /var/lib/snapd/snap/snapd/25577 tmpfs 268M 8.0K 268M 1% /run/user/1000 |
②使用率80%以上になるようダミーファイルを作成(例ではdummyfile という名前で6G程度)
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# dd if=/dev/zero of=dummyfile bs=1M count=6000 |
③再度確認
下記を実行して80%以上になっていることを確認
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# df -h |
④ディスク容量チェックスクリプトを実行
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# /var/www/system/disk_capacity_check.sh |
設定したメールアドレスに本文の内容として「Disk usage alert: 85 %」のように記載のメールが届きます
⑤作成した「dummyfile」を削除
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# rm dummyfile |
⑥定期実行設定
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# crontab -e 下記追加 30 2 * * * /var/www/system/disk_capacity_check.sh |
