Deploying OpenStack with kolla-ansible

I’ve been trying to deploy openstack using kolla-ansible method according to this guide
but when running:
kolla-ansible -i all-in-one bootstrap-servers -vvv
I get this error after completing few first Tasks:

[WARNING]: Updating cache and auto-installing missing dependency: python3-apt
fatal: [localhost]: FAILED! => {
“changed”: false,
“cmd”: “apt-get update”,
“invocation”: {
“module_args”: {
“allow_downgrade”: false,
“allow_unauthenticated”: false,
“autoclean”: false,
“autoremove”: false,
“cache_valid_time”: 0,
“deb”: null,
“default_release”: null,
“dpkg_options”: “force-confdef,force-confold”,
“fail_on_autoremove”: false,
“force”: false,
“force_apt_get”: false,
“install_recommends”: null,
“lock_timeout”: 60,
“only_upgrade”: false,
“package”: null,
“policy_rc_d”: null,
“purge”: false,
“state”: “present”,
“update_cache”: true,
“update_cache_retries”: 5,
“update_cache_retry_max_delay”: 12,
“upgrade”: “no”
}
},
“msg”: “W: GPG error: https://download.docker.com/linux/ubuntu bionic InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 7EA0A9C3F273FCD8\nE: The repository ‘https://download.docker.com/linux/ubuntu bionic InRelease’ is not signed.”,
“rc”: 100,
“stderr”: “W: GPG error: https://download.docker.com/linux/ubuntu bionic InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 7EA0A9C3F273FCD8\nE: The repository ‘https://download.docker.com/linux/ubuntu bionic InRelease’ is not signed.\n”,
“stderr_lines”: [
“W: GPG error: https://download.docker.com/linux/ubuntu bionic InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 7EA0A9C3F273FCD8”,
“E: The repository ‘https://download.docker.com/linux/ubuntu bionic InRelease’ is not signed.”
],
“stdout”: “Hit:1 http://ir.archive.ubuntu.com/ubuntu bionic InRelease\nHit:2 http://ir.archive.ubuntu.com/ubuntu bionic-updates InRelease\nHit:3 http://ir.archive.ubuntu.com/ubuntu bionic-backports InRelease\nHit:4 http://ir.archive.ubuntu.com/ubuntu bionic-security InRelease\nHit:5 http://ppa.launchpad.net/deadsnakes/ppa/ubuntu bionic InRelease\nGet:6 https://download.docker.com/linux/ubuntu bionic InRelease [64.4 kB]\nErr:6 https://download.docker.com/linux/ubuntu bionic InRelease\n The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 7EA0A9C3F273FCD8\nReading package lists…\n”,
“stdout_lines”: [
“Hit:1 http://ir.archive.ubuntu.com/ubuntu bionic InRelease”,
“Hit:2 http://ir.archive.ubuntu.com/ubuntu bionic-updates InRelease”,
“Hit:3 http://ir.archive.ubuntu.com/ubuntu bionic-backports InRelease”,
“Hit:4 http://ir.archive.ubuntu.com/ubuntu bionic-security InRelease”,
“Hit:5 http://ppa.launchpad.net/deadsnakes/ppa/ubuntu bionic InRelease”,
“Get:6 https://download.docker.com/linux/ubuntu bionic InRelease [64.4 kB]”,
“Err:6 https://download.docker.com/linux/ubuntu bionic InRelease”,
" The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 7EA0A9C3F273FCD8",
“Reading package lists…”
]
}