Usage of async in ansible task raised privileged errors - ansible

Question

I get puzzled a lot of time with the following issue.
I try so launch a process (here just a silly java -version) using async feature.
I run the ansible-playbook using my user which has a remote account as sudoer in the docker host. The other account with which I'd like to start the command is toto
So I wrote this
- name: test escalation
shell: id ; echo "shell says toto"
become: true
become_user: "toto"
tags:
- escalation
vars:
ansible_ssh_pipelining: true
- name: java escalation
shell:
cmd: "/data/tools/java/jdk8u232-b09/bin/java -version &"
async: 10
# Don't wait
poll: 0
become: true
become_user: "toto"
tags:
- escalation
vars:
ansible_ssh_pipelining: true
If i run this, I have
TASK [java escalation] ************************************************************************************************************
fatal: [main]: FAILED! => {"msg": "Failed to set permissions on the temporary files Ansible needs to create when becoming an unprivileged user (rc: 1, err: chown: changing ownership of '/var/tmp/ansible-tmp-1587484730.23-27264-164045960304097/': Operation not permitted\nchown: changing ownership of '/var/tmp/ansible-tmp-1587484730.23-27264-164045960304097/AnsiballZ_command.py': Operation not permitted\nchown: changing ownership of '/var/tmp/ansible-tmp-1587484730.23-27264-164045960304097/async_wrapper.py': Operation not permitted\n}). For information on working around this, see https://docs.ansible.com/ansible/become.html#becoming-an-unprivileged-user"}
Did anybody had the same issue ?
ansible --version
ansible 2.9.7

Answer 1

If I do not use the async feature (I can use any value for poll)
- name: java escalation
shell:
cmd: "/data/tools/java/jdk8u232-b09/bin/java -version &"
# async: 10
# Don't wait
poll: 0
become: true
become_user: "toto"
tags:
- escalation
vars:
ansible_ssh_pipelining: true
It works fine
TASK [ java escalation] ************************************************************************************************************
changed: [main] => {"changed": true, "cmd": "/data/tools/java/jdk8u232-b09/bin/java -version &", "delta": "0:00:00.034427", "end": "2020-04-21 15:59:46.402081", "rc": 0, "start": "2020-04-21 15:59:46.367654", "stderr": "openjdk version \"1.8.0_232\"\nOpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_232-b09)\nOpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.232-b09, mixed mode)", "stderr_lines": ["openjdk version \"1.8.0_232\"", "OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_232-b09)", "OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.232-b09, mixed mode)"], "stdout": "", "stdout_lines": []}