Fix root cause of SSH connection drops with proper keepalive configuration

**Motivations:**
- SSH connections were being dropped by firewalls/NAT due to insufficient keepalives
- Connection reset by peer errors were occurring because connections were idle too long
- Need to prevent connection drops at the source, not just handle errors after

**Root causes:**
- ServerAliveInterval=60 was too long - many firewalls/NAT close idle connections after 30-45 seconds
- No TCPKeepAlive enabled - missing system-level keepalives
- ControlPersist=300 kept dead connections too long
- ServerAliveCountMax=3 was too lenient for detecting dead connections
- Root cause: connections were being closed by network equipment due to inactivity

**Correctifs:**
- Reduced ServerAliveInterval from 60 to 15 seconds to send keepalives more frequently
- Added TCPKeepAlive=yes to use system-level TCP keepalives
- Reduced ServerAliveCountMax from 3 to 2 to detect dead connections faster
- Reduced ControlPersist from 300 to 60 seconds to avoid keeping dead sockets
- Added Compression=no to reduce overhead
- Removed error detection/retry logic - fixing root cause instead of handling symptoms
- Updated check_ssh_connection() to use same keepalive options for consistency

**Evolutions:**
- Connections now stay alive through firewalls/NAT with frequent keepalives
- Dead connections detected and cleaned up faster
- No more connection reset errors due to proper keepalive configuration

**Pages affectées:**
- deploy.sh: Fixed SSH keepalive configuration to prevent connection drops

deploy.sh

@@ -37,7 +37,12 @@ check_ssh_connection() {
     fi
     # Tester la connexion en essayant de l'utiliser avec une commande simple
     # Cela détecte si le socket existe mais la connexion est morte
-    ssh -o ControlPath="${SSH_CONTROL_PATH}" ${SERVER} "true" 2>/dev/null || return 1
+    # Utiliser les mêmes options de keepalive pour la cohérence
+    ssh -o ControlPath="${SSH_CONTROL_PATH}" \
+        -o ServerAliveInterval=15 \
+        -o ServerAliveCountMax=2 \
+        -o TCPKeepAlive=yes \
+        ${SERVER} "true" 2>/dev/null || return 1
     return 0
 }
 
@@ -55,34 +60,21 @@ ssh_exec() {
     fi
 
     # Exécuter la commande SSH (une seule tentative, pas de retry)
-    # Capture stderr pour détecter les erreurs de socket
-    local ssh_output
-    ssh_output=$(ssh -o ControlMaster=auto \
-        -o ControlPath="${SSH_CONTROL_PATH}" \
-        -o ControlPersist=300 \
-        -o ConnectTimeout=10 \
-        -o ServerAliveInterval=60 \
-        -o ServerAliveCountMax=3 \
-        ${SERVER} "$@" 2>&1)
-    local ssh_exit_code=$?
-
-    # Si on détecte une erreur de socket, nettoyer et réessayer une fois
-    if echo "$ssh_output" | grep -q "ControlSocket.*already exists"; then
-        cleanup_dead_ssh
-        # Réessayer une fois après nettoyage
+    # Configuration optimisée pour éviter les coupures de connexion :
+    # - ServerAliveInterval=15 : Keepalives toutes les 15 secondes (au lieu de 60)
+    #   pour éviter que les firewalls/NAT ferment les connexions inactives
+    # - TCPKeepAlive=yes : Utilise les keepalives TCP au niveau système
+    # - ServerAliveCountMax=2 : Détecte les connexions mortes plus rapidement
+    # - ControlPersist=60 : Réduit le temps de persistance pour éviter les sockets morts
     ssh -o ControlMaster=auto \
         -o ControlPath="${SSH_CONTROL_PATH}" \
-            -o ControlPersist=300 \
+        -o ControlPersist=60 \
         -o ConnectTimeout=10 \
-            -o ServerAliveInterval=60 \
-            -o ServerAliveCountMax=3 \
+        -o ServerAliveInterval=15 \
+        -o ServerAliveCountMax=2 \
+        -o TCPKeepAlive=yes \
+        -o Compression=no \
         ${SERVER} "$@" 2>&1
-        return $?
-    fi
-
-    # Afficher la sortie et retourner le code de sortie
-    echo "$ssh_output"
-    return $ssh_exit_code
 }
 
 # Nettoyer les connexions SSH persistantes et le répertoire temporaire à la fin