Nettoyage logs & espace disque

Script de maintenance : purge des logs anciens, nettoyage journald, /tmp et rapport d'espace.

Script

#!/bin/bash
nettoyage-logs.sh — Purge logs, journald, /tmp + rapport espace
Usage : ./nettoyage-logs.sh [--dry-run] [--retention-days 30]

set -uo pipefail

── Configuration ─────────────────────────────────────────────
LOG_RETENTION_DAYS=30      # Logs système
TMP_RETENTION_HOURS=24     # Fichiers /tmp
JOURNALD_RETENTION="2weeks"
DRY_RUN=false
REPORT_FILE="/var/log/nettoyage-$(date +%Y%m%d).log"
MIN_FREE_GB=5              # Alerte si espace libre < X Go

── Parse arguments ───────────────────────────────────────────
for arg in "$@"; do
  case $arg in
    --dry-run)           DRY_RUN=true ;;
    --retention-days=)  LOG_RETENTION_DAYS="${arg#=}" ;;
  esac
done

── Fonctions ─────────────────────────────────────────────────
log() { echo "[$(date '+%H:%M:%S')] $*" | tee -a "$REPORT_FILE"; }
run() {
  if $DRY_RUN; then
    log "  [DRY-RUN] $*"
  else
    eval "$@" 2>&1 | while IFS= read -r line; do log "  $line"; done
  fi
}

disk_free_gb() { df -BG "$1" | awk 'NR==2{gsub("G","",$4); print $4}'; }
human_size()   { du -sh "$1" 2>/dev/null | cut -f1; }

── Header ────────────────────────────────────────────────────
log "════════════════════════════════════════"
log " Nettoyage système — $(hostname)"
log " Mode: $( $DRY_RUN && echo 'DRY-RUN (simulation)' || echo 'RÉEL')"
log "════════════════════════════════════════"

── Espace avant ──────────────────────────────────────────────
log ""
log "📊 Espace disque AVANT"
df -h / /var /tmp 2>/dev/null | tee -a "$REPORT_FILE"

── 1. Logs système /var/log ───────────────────────────────────
log ""
log "📁 Logs anciens (>${LOG_RETENTION_DAYS}j) dans /var/log"
LOGS_SIZE=$(find /var/log -type f \( -name ".log" -o -name ".log." -o -name ".gz" \) \
  -mtime +"$LOG_RETENTION_DAYS" -print 2>/dev/null | \
  xargs -r du -ch 2>/dev/null | tail -1 | cut -f1)
log "  Taille à supprimer : ${LOGS_SIZE:-0}"

run "find /var/log -type f \( -name '.log.' -o -name '*.gz' \) \
  -mtime +${LOG_RETENTION_DAYS} -delete -print 2>/dev/null | \
  wc -l | xargs -I{} echo '{} fichier(s) supprimé(s)'"

Tronquer les gros logs actifs (ne pas les supprimer)
for logfile in /var/log/syslog /var/log/auth.log /var/log/kern.log; do
  if [[ -f "$logfile" ]]; then
    SIZE_MB=$(du -sm "$logfile" | cut -f1)
    if [[ $SIZE_MB -gt 100 ]]; then
      log "  ⚠ $logfile volumineux (${SIZE_MB}MB) — troncature"
      run "truncate -s 10M $logfile"
    fi
  fi
done

── 2. Journald ───────────────────────────────────────────────
log ""
log "📋 Nettoyage journald (rétention: $JOURNALD_RETENTION)"
JOURNALD_BEFORE=$(journalctl --disk-usage 2>/dev/null | grep -oP '[\d.]+ [A-Z]' || echo "?")
log "  Taille actuelle : $JOURNALD_BEFORE"
run "journalctl --vacuum-time=$JOURNALD_RETENTION --vacuum-size=500M"

── 3. /tmp ───────────────────────────────────────────────────
log ""
log "🗑  Fichiers /tmp (>${TMP_RETENTION_HOURS}h)"
TMP_SIZE=$(find /tmp -type f -atime +"$(( TMP_RETENTION_HOURS / 24 ))" \
  -print 2>/dev/null | xargs -r du -ch 2>/dev/null | tail -1 | cut -f1)
log "  Taille à supprimer : ${TMP_SIZE:-0}"
run "find /tmp -type f -atime +$(( TMP_RETENTION_HOURS / 24 )) -delete 2>/dev/null || true"
run "find /tmp -mindepth 1 -maxdepth 1 -type d -empty -delete 2>/dev/null || true"

── 4. Cache apt/dnf ─────────────────────────────────────────
log ""
log "📦 Cache gestionnaire de paquets"
if command -v apt-get &>/dev/null; then
  log "  apt cache : $(du -sh /var/cache/apt/archives 2>/dev/null | cut -f1)"
  run "apt-get clean -y"
elif command -v dnf &>/dev/null; then
  run "dnf clean all"
elif command -v yum &>/dev/null; then
  run "yum clean all"
fi

── 5. Anciens kernels (Debian/Ubuntu) ───────────────────────
if command -v dpkg &>/dev/null; then
  log ""
  log "🐧 Anciens kernels"
  CURRENT_KERNEL=$(uname -r)
  OLD_KERNELS=$(dpkg --list 'linux-image-*' | \
    awk '/^ii/{print $2}' | \
    grep -v "$CURRENT_KERNEL" | \
    grep -v 'linux-image-generic' || true)
  if [[ -n "$OLD_KERNELS" ]]; then
    log "  Kernels à supprimer : $(echo "$OLD_KERNELS" | wc -l)"
    run "apt-get purge -y $OLD_KERNELS"
  else
    log "  Aucun ancien kernel trouvé"
  fi
fi

── 6. Rapport final ──────────────────────────────────────────
log ""
log "📊 Espace disque APRÈS"
df -h / /var /tmp 2>/dev/null | tee -a "$REPORT_FILE"

Alerte espace libre
FREE_GB=$(disk_free_gb /)
if [[ "$FREE_GB" -lt "$MIN_FREE_GB" ]]; then
  log "⚠️  ALERTE : Espace libre insuffisant (${FREE_GB}Go < ${MIN_FREE_GB}Go seuil)"
fi

log ""
log "✅ Nettoyage terminé — rapport : $REPORT_FILE"

Installation cron

# Nettoyage hebdomadaire (dimanche 3h)
echo "0 3   0 root /opt/scripts/nettoyage-logs.sh >> /var/log/nettoyage.log 2>&1" \
  > /etc/cron.d/nettoyage-logs