DOCKER_HOST and docker command not found in PATH

[pidumenk]

Issue Type

• Bug report

Molecule and Ansible details

ansible --version && molecule --version
ansible [core 2.11.4]
config file = /etc/ansible/ansible.cfg
configured module search path = ['/home/user/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
ansible python module location = /opt/molecule-venv/lib/python3.8/site-packages/ansible
ansible collection location = /home/user/.ansible/collections:/usr/share/ansible/collections
executable location = /opt/molecule-venv/bin/ansible
python version = 3.8.10 (default, Jun 2 2021, 10:49:15) [GCC 9.4.0]
jinja version = 3.0.1
libyaml = True
molecule 3.4.0 using python 3.8
ansible:2.11.4
delegated:3.4.0 from molecule
docker:1.0.2 from molecule_docker requiring collections: community.docker>=1.8.0

Molecule installation method (one of):

• pip install molecule[docker,lint]

Ansible installation method (one of):

• pip

Detail any linters or test runners used:

Desired Behavior

When I use molecule to test roles in docker containers on a remote machine, I suppose my scenario will be executed on the remote docker specified via environment variable DOCKER_HOST.

Actual Behaviour

On the converge step I currently faced with an error sounds like "msg: docker command not found in PATH". I don't have docker installed on my master host with molecule because I had configured remote docker daemon on a target host by tcp://0.0.0.0:2376.
I don't understand as well how to specify docker_host or docker_tls_verify and docker_cert_path inside molecule.yml. Only one working way that I've found is to add them in my ~/.bashrc.

[tadeboro]

Hi @pidumenk!

Looking at the https://github.com/ansible-community/molecule-docker/blob/main/src/molecule_docker/playbooks/create.yml, I would say that things should work (and you can also see which env variables molecule uses as a source of the various docker-related pieces of data).

Can you please post the error output here? It would be interesting to see which module actually fails.

[pidumenk]

@tadeboro, have you managed to repeat the error? I have no idea how to avoid this issue starting "molecule converge" without docker installed on my master host (there are only python-docker and molecule dependencies) .

I'm using venv and my pip list consists of the next items:

pip list | egrep "docker|ansible|lint"
ansible-base                      2.10.13
ansible-compat                    0.5.0
ansible-lint                      5.1.3
docker                            5.0.2
molecule-docker                   1.0.2
yamllint                          1.26.3

These variables are specified in my ~/.bashrc:

DOCKER_HOST=<host_name>
DOCKER_TLS_HOSTNAME=<host_name>
DOCKER_TLS_VERIFY=1
DOCKER_CERT_PATH=<path_to_certs>

It seems like molecule is looking for local docker-client, but "create" step have been made well on a target host (where docker is installed). Only "converge" things fail with a message: docker command not found in PATH. Could you, please, give any advise for this issue?

[pidumenk]

@tadeboro @ssbarnea

[ssbarnea]

run which docker to see if you have docker in path. That is not about docker python library, is about docker executable itself.

[pidumenk]

@ssbarnea, I don't have docker installed on my host where molecule is. The main idea is using remote docker in order to avoid loading the master host by additional sevices.

$which docker
/usr/bin/which: no docker in (/opt/molecule-env/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/home/dumenko/.local/bin:/home/dumenko/bin)

The debug showed me (attached above files) that a problem probably is coming from this line:
Loading collection community.docker from /home/dumenko/.ansible/collections/ansible_collections/community/docker

I had looked up in my ~/.cache/molecule/role_1/default/inventory/ansible_inventory.yml before I found the next configuration by default:

---
all:
  hosts:
    centos7_container: &id001
      ansible_connection: community.docker.docker
---

It refers to community.docker.docker plugins which assumes to use Docker CLI. I've changed it for community.docker.docker_api in order to communicate with Docker SDK for python on provisioner section in my molecule.yml.

provisioner:
  name: ansible
  connection_options:
    ansible_connection: community.docker.docker_api
  inventory:
    host_vars:
      centos7_container:
        ansible_docker_docker_host: tcp://FQDN:2376
        ansible_docker_ca_cert: /path/to/ca.pem
        ansible_docker_client_cert: /path/to/cert.pem
        ansible_docker_client_key: /path/to/key.pem
        ansible_docker_tls_hostname: FQDN
        ansible_docker_validate_certs: yes

@ssbarnea, If I'm not mistaken, you had expertise configuring remote docker using molecule. At least I read info on your web-page. How did you set these parameters? Did not you have local docker client and engine on your master host?

[ssbarnea]

If I remember correctly molecule-docker still requires docker cli to be present on the host, having docker python library is likely not enough for it to function. You do not need to have the sever running as you can use remote docker host (that is what I also do). If is possible to avoid that you are more more than welcomed to make a pull-request on molecule-docker to drop that requirement.

[pidumenk]

According to this case, I've found a solution to use remote docker-daemon as I had mentioned before: just setting up community.docker.docker plugin in molecule.yml with additional parameters.

provisioner:
  name: ansible
  connection_options:
    ansible_connection: community.docker.docker_api