Help - No Space Left on device

[He Rugen]

Hello all, I'm customizing my own Raspbian OS, I need to upload some docker images to it and apt install some tools, but it returns No space left on device, I'm not familiar with disk partition configuration, how should I do to make a larger disk to continue?
Here's my configuration:

    "image_build_method": "new",
    "image_size": "6G",
    "image_type": "dos",
    "image_partitions": [
      {
        "name": "boot",
        "type": "c",
        "start_sector": "8192",
        "filesystem": "vfat",
        "size": "1024M",
        "mountpoint": "/boot"
      },
      {
        "name": "root",
        "type": "83",
        "start_sector": "2097152",
        "filesystem": "ext4",
        "size": "0",
        "mountpoint": "/"
      }
    ],

[He Rugen]

Fixed:

"image_build_method": "resize",