Trouble building ubuntu core images. Error creating mount directory: mkdir /tmp/.../etc/resolv.conf file exists

[gshiva]

Trying to build 64 bit ubuntu core image and getting the following error.

==> arm-image: Growing partition with 1024 M (1073741824 bytes)
    arm-image: mapping output-arm-image/image
==> arm-image: kpartx -s -a -v output-arm-image/image
==> arm-image: partitions: [/dev/mapper/loop1p1 /dev/mapper/loop1p2]
==> arm-image: partitions: [/dev/mapper/loop1p1 /dev/mapper/loop1p2]
    arm-image: Mounting: /dev/mapper/loop1p2
    arm-image: Mounting: /dev/mapper/loop1p1
==> arm-image: Mounting additional paths within the chroot...
    arm-image: Mounting: /proc
    arm-image: Mounting: /sys
    arm-image: Mounting: /dev
    arm-image: Mounting: /dev/pts
    arm-image: Mounting: /proc/sys/fs/binfmt_misc
==> arm-image: Error creating mount directory: mkdir /tmp/108605975/etc/resolv.conf: file exists
==> arm-image: fuser -k /tmp/108605975
Build 'arm-image' errored: Error creating mount directory: mkdir /tmp/108605975/etc/resolv.conf: file exists

==> Some builds didn't complete successfully and had errors:
--> arm-image: Error creating mount directory: mkdir /tmp/108605975/etc/resolv.conf: file exists

==> Builds finished but no artifacts were created.

the json file:

{
  "variables": {
    "home": "{{env `HOME`}}"
  },
  "builders": [{
    "type": "arm-image",
    "image_type": "raspberrypi",
    "qemu_binary": "qemu-aarch64-static",
    "iso_url" : "http://cdimage.ubuntu.com/releases/20.04/release/ubuntu-20.04-preinstalled-server-arm64+raspi.img.xz",
    "iso_checksum_type":"sha256",
    "iso_checksum":"48167067d65c5192ffe041c9cc4958cb7fcdfd74fa15e1937a47430ed7b9de99",
    "last_partition_extra_size" : 1073741824
  }],
  "provisioners": [
    {
      "type": "shell",
      "inline": ["touch /boot/ssh"]
    },
    {
      "type": "file",
      "source": "/.ssh/id_rsa.pub",
      "destination": "/home/pi/.ssh/authorized_keys"
    },
    {
      "type": "shell",
      "inline": [
        "sed '/PasswordAuthentication/d' -i /etc/ssh/ssh_config",
        "echo  >> /etc/ssh/ssh_config",
        "echo 'PasswordAuthentication no' >> /etc/ssh/ssh_config"
      ]
    },
    {
      "type": "shell",
      "inline": [
	      "apt-get update",
	      "apt-get install -y zfs-dkms, atop",
	      "curl -SL https://github.com/prometheus/node_exporter/releases/download/v0.18.1/node_exporter-0.18.1.linux-armv7.tar.gz > node_exporter.tar.gz",
	      "sudo tar -xvf node_exporter.tar.gz -C /usr/local/bin/ --strip-components=1",
	      "cd /etc/systemd/system/",
              "curl -sSLo - https://raw.githubusercontent.com/prometheus/node_exporter/master/examples/systemd/node_exporter.service |sed -e 's|/etc/sysconfig/node_exporter|/etc/default/node_exporter|' |sed -e 's/^User.*//'  > node_exporter.service",
               "curl -sSLo - https://raw.githubusercontent.com/prometheus/node_exporter/master/examples/systemd/sysconfig.node_exporter  |sed -e 's/^OPTIONS/#OPTIONS/;aOPTIONS=\"\"' >/etc/default/node_exporter",
               "systemctl daemon-reload",
               "systemctl enable node_exporter.service",
               "systemctl start node_exporter.service"
      ]
    }
  ]
}```

[gshiva]

Related to #58, #36 #22 ?

Using information from #36 I was able to get the build going. Then I saw #58 also reporting the same issue.

I have attached a pull request #64 to add a ubuntu core sample for others to avoid running into the same issue.