Ansible

Ansible is an open-source automation tool.

Ansible is a tool that helps you automate tasks on your remote machines (robots) — like installing software, updating settings, or running scripts — without doing it manually on each machine.

You just need to write instructions in simple text files (called playbooks) using YAML, and Ansible follows them. It connects over SSH, so you don’t need to install anything extra on the machines you're managing.

To install Ansible on your machine, refer to the Installation Guide.

Setting on the remote machine(s)

• Ensure the public SSH key is added to ~/.ssh/authorized_keys.
  After you generate your SSH key (e.g., ~/.ssh/ansible), you can copy it to the remote machine using:

ssh-copy-id -i ~/.ssh/ansible remote_user@192.168.69.1xx

Playbook examples

Example Transfer and load Docker image

- name: Transfer and load Docker image 
  hosts: remote
  become: yes
  serial: 0  
  tasks:
    - name: Copy Docker image to remote machine
      ansible.builtin.copy:
        src: "~/docker/shared_data:worlds.tar.gz"
        dest: "/tmp/tmp_img.tar.gz"
        mode: '0644'

    - name: Load Docker image on remote machine
      ansible.builtin.shell: docker load -i /tmp/tmp_img.tar.gz
      register: docker_load_output

    - name: Show Docker load output
      ansible.builtin.debug:
        msg: "{{ docker_load_output.stdout }}"

Example Fetch rosbags

- name: Fetch .bag files from remote to local
  hosts: remote
  become: yes
  serial: 0
  tasks:

    - name: Ensure temp directory exists
      ansible.builtin.file:
        path: /tmp/rosbags
        state: directory
        mode: '0755'

    - name: Copy .bag files to temp directory
      ansible.builtin.shell: |
        cp /var/lib/docker/volumes/stack_bag_files/_data/*.bag /tmp/rosbags/
      args:
        executable: /bin/bash

    - name: Get list of .bag files
      ansible.builtin.find:
        paths: /tmp/rosbags
        patterns: "*.bag"
      register: bag_files

    - name: Fetch .bag files one by one
      ansible.builtin.fetch:
        src: "{{ item.path }}"
        dest: "~/rosbags/{{ inventory_hostname }}/"
        flat: yes
      loop: "{{ bag_files.files }}"

Usage

Once the .yml file is created you can run the following command:

ansible-playbook -i inventory.ini load_docker_image.yml --ask-become-pass

where inventory.ini is the file that contains the list of remote machines:

[remote]
192.168.69.160 ansible_user=uav 
192.168.69.161 ansible_user=uav 
192.168.69.162 ansible_user=uav 
192.168.69.163 ansible_user=uav 
192.168.69.164 ansible_user=uav 
192.168.69.165 ansible_user=uav 
192.168.69.166 ansible_user=uav 
192.168.69.167 ansible_user=uav 
192.168.69.168 ansible_user=uav 
192.168.69.169 ansible_user=uav 

and in a file named ansible.cfg you can specify the private key to use e.g.:

[defaults]
private_key_file = ~/.ssh/ansible