Why Molecule is not able to start a docker container (Failed to create temporary directory) - molecule

Question

I found similar case here, that I am using molecule to test my ansible roles, but for some reason it is skipping "creation" part and gives error like:
fatal: [rabbitmq]: UNREACHABLE! => {"changed": false, "msg": "Failed to create temporary directory.In some cases, you may have been able to authenticate and did not have permissions on the target directory. Consider changing the remote tmp path in ansible.cfg to a path rooted in \"/tmp\", for more error information use -vvv. Failed command was: ( umask 77 && mkdir -p \"` echo ~/.ansible/tmp `\"&& mkdir \"` echo ~/.ansible/tmp/ansible-tmp-1638541586.6239848-828-250053975102429 `\" && echo ansible-tmp-1638541586.6239848-828-250053975102429=\"` echo ~/.ansible/tmp/ansible-tmp-1638541586.6239848-828-250053975102429 `\" ), exited with result 1", "unreachable": true}
It is skipping the create process: Skipping, instances already created. However, nothing is running:
name#EEW00438:~/.cache$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
name#EEW00438:~/.cache$
what I tried:
molecule destroy
molecule reset
restart
rm -rf ~/.cache/
changed remote_tmp to /tmp/.ansible/ in /etc/ansible/ansible.cfg
reinstall molecule
This issue is only with one role.
UPDATE:
it is failing on step:
mkdir \"` echo ~/.ansible/tmp/ansible-tmp-1638782939.31706-2913-12516475286623 `\" && echo ansible-tmp-1638782939.31706-2913-12516475286623=
mkdir: cannot create directory ‘"/home/user/.ansible/tmp/ansible-tmp-1638782939.31706-2913-12516475286623"’: No such file or directory

Answer 1

I stumbled upon this issue as well.
When you create the role you need to create it as molecule init role --driver-name docker ns.myrole to enable docker. Be sure to install the docker driver too if you haven't pip install --upgrade molecule-docker
So if you need to tweak the container that runs, edit molecule.yml. It defaults to centos. I switched to ubuntu in there, an created a Dockerfile to provision the container with things that need to exist.
molecule.yml
---
dependency:
name: galaxy
driver:
name: docker
platforms:
- name: instance
image: ubuntu:22.04 # this is required but ignored since I specify a `dockerfile`
pre_build_image: false
dockerfile: Dockerfile
provisioner:
name: ansible
verifier:
name: ansible
For example, Ubuntu 22.04 doesn't use python anymore, so I added an alias at the end of what molecule renders so that Ansible can use python and have it redirect to python3
FROM ubuntu:22.04
RUN if [ $(command -v apt-get) ]; then export DEBIAN_FRONTEND=noninteractive && apt-get update && apt-get install -y python3 sudo bash ca-certificates iproute2 python3-apt aptitude && apt-get clean && rm -rf /var/lib/apt/lists/*; \
elif [ $(command -v dnf) ]; then dnf makecache && dnf --assumeyes install /usr/bin/python3 /usr/bin/python3-config /usr/bin/dnf-3 sudo bash iproute && dnf clean all; \
elif [ $(command -v yum) ]; then yum makecache fast && yum install -y /usr/bin/python /usr/bin/python2-config sudo yum-plugin-ovl bash iproute && sed -i 's/plugins=0/plugins=1/g' /etc/yum.conf && yum clean all; \
elif [ $(command -v zypper) ]; then zypper refresh && zypper install -y python3 sudo bash iproute2 && zypper clean -a; \
elif [ $(command -v apk) ]; then apk update && apk add --no-cache python3 sudo bash ca-certificates; \
elif [ $(command -v xbps-install) ]; then xbps-install -Syu && xbps-install -y python3 sudo bash ca-certificates iproute2 && xbps-remove -O; fi
RUN echo 'alias python=python3' >> ~/.bashrc
It's been years since I last used Molecule, and I must say... it's gone downhill. It used to be easy/clear/direct to get things working. Sigh. I guess I should stick to containers and force the migration off VMs sooner!

Answer 2

The problem may be caused by a Docker context change performed at the start of Docker Desktop. Despite this, Molecule does create a container, but in an inactive context.
At startup, Docker Desktop automatically switches the context from default to desktop-linux [1]. The active context determines which containers are available from CLI.
The context cannot be set in the molecule, i.e. the default context is always used to create containers [2].
$ molecule create --scenario-name test
... # The output with the error is skipped because it duplicates the output from the question
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
$ docker context ls
NAME TYPE DESCRIPTION DOCKER ENDPOINT KUBERNETES ENDPOINT ORCHESTRATOR
default moby Current DOCKER_HOST based configuration unix:///var/run/docker.sock swarm
desktop-linux * moby unix:///home/bkarpov/.docker/desktop/docker.sock
$ docker context use default
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
a71bfd28992f geerlingguy/docker-ubuntu2004-ansible "bash -c 'while true…" 5 minutes ago Up 5 minutes some-instance
$ molecule login --scenario-name test
INFO Running test > login
root#some-instance:/#
Solutions
Switch the context back to default manually
docker context use default
This solution is suitable for one-time execution, since the context will need to be switched every time Docker Desktop is started. Docker Desktop service will continue to work using the desktop-linux context.
Issue with the request to add context switching to Docker Desktop - https://github.com/docker/roadmap/issues/47
Stop Docker Desktop
systemctl --user stop docker-desktop
Stopping the Docker Desktop service will automatically switch to the default context.
Set DOCKER_CONTEXT so that Docker Desktop does not change the context in the current shell
export DOCKER_CONTEXT=default
systemctl --user restart docker-desktop
When stopping, the context returns to default, and when starting, it does not switch to desktop-linux.
References
https://docs.docker.com/desktop/install/ubuntu/#launch-docker-desktop
https://github.com/ansible-community/molecule-docker#faq