align sonic vm backup script with dell_sonic (#245)

sonic/docker/backup.sh

@@ -32,9 +32,9 @@ handle_args() {
         password=$DEFAULT_PASSWORD
     fi
 
-    SSH_CMD="sshpass -p $password ssh -o LogLevel=ERROR -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -p 2022"
-    SCP_CMD="sshpass -p $password scp -o LogLevel=ERROR -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -P 2022"
-    HOST="$user@127.0.0.1"
+    SSH_CMD="sshpass -p $password ssh -o LogLevel=ERROR -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null"
+    SCP_CMD="sshpass -p $password scp -o LogLevel=ERROR -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null"
+    HOST="$user@localhost"
 
     # Parse commands
     case $1 in
@@ -66,17 +66,41 @@ usage() {
 }
 
 backup() {
-    echo "Backing up..."
-    $SCP_CMD $HOST:$REMOTE_FILE $BACKUP_FILE
+    echo "Retrieveing the config from the VM..."
+    # copy the original config to the tmp location and set permissions to 777
+    # and then copy out the file from the temp location
+    $SSH_CMD $HOST "sudo cp $REMOTE_FILE $TMP_FILE && sudo chmod 777 $TMP_FILE" && \
+    $SCP_CMD $HOST:$TMP_FILE $BACKUP_FILE
+}
+
+wait_for_ssh() {
+    local max_retries=30
+    local retry_interval=2
+
+    for ((i=1; i<=$max_retries; i++)); do
+        echo "Waiting for VM's SSH to become available... (Attempt $i/$max_retries)"
+        if $SSH_CMD -o ConnectTimeout=5 $HOST exit 2>/dev/null; then
+            echo "SSH connection established."
+            return 0
+        fi
+        sleep $retry_interval
+    done
+
+    echo "SSH connection could not be established after $max_retries attempts."
+    return 1
 }
 
 restore() {
     if [ -f "$BACKUP_FILE" ]; then
-        echo "Restoring from backup..."
+        echo "Copying startup config file to the VM..."
 
-        $SCP_CMD $BACKUP_FILE $HOST:$TMP_FILE && $SSH_CMD $HOST "sudo cp $TMP_FILE $REMOTE_FILE && sudo config reload -y -f || true"
+        if wait_for_ssh; then
+            $SCP_CMD $BACKUP_FILE $HOST:$TMP_FILE && $SSH_CMD $HOST "sudo config load -y $TMP_FILE && sudo config save -y"
+        else
+            echo "Failed to establish SSH connection. Config copy operation aborted."
+        fi
     else
-        echo "$BACKUP_FILE not found. Nothing to restore."
+        echo "$BACKUP_FILE not found. Nothing to push to the VM."
     fi
 }