Ansible non-root sudo user and "become" privilege escalation - ansible

Question

I've set up a box with a user david who has sudo privileges. I can ssh into the box and perform sudo operations like apt-get install. When I try to do the same thing using Ansible's "become privilege escalation", I get a permission denied error. So a simple playbook might look like this:
simple_playbook.yml:
---
- name: Testing...
hosts: all
become: true
become_user: david
become_method: sudo
tasks:
- name: Just want to install sqlite3 for example...
apt: name=sqlite3 state=present
I run this playbook with the following command:
ansible-playbook -i inventory simple_playbook.yml --ask-become-pass
This gives me a prompt for a password, which I give, and I get the following error (abbreviated):
fatal: [123.45.67.89]: FAILED! => {...
failed: E: Could not open lock file /var/lib/dpkg/lock - open (13:
Permission denied)\nE: Unable to lock the administration directory
(/var/lib/dpkg/), are you root?\n", ...}
Why am I getting permission denied?
Additional information
I'm running Ansible 2.1.1.0 and am targeting a Ubuntu 16.04 box. If I use remote_user and sudo options as per Ansible < v1.9, it works fine, like this:
remote_user: david
sudo: yes
Update
The local and remote usernames are the same. To get this working, I just needed to specify become: yes (see #techraf's answer):

Answer 1

Why am I getting permission denied?
Because APT requires root permissions (see the error: are you root?) and you are running the tasks as david.
Per these settings:
become: true
become_user: david
become_method: sudo
Ansible becomes david using sudo method. It basically runs its Python script with sudo david in front.
the user 'david' on the remote box has sudo privileges.
It means david can execute commands (some or all) using sudo-executable to change the effective user for the child process (the command). If no username is given, this process runs as the root account.
Compare the results of these two commands:
$ sudo whoami
root
$ sudo david whoami
david
Back to the APT problem, you (from CLI) as well as Ansible (connecting with SSH using your account) need to run:
sudo apt-get install sqlite3
not:
sudo david apt-get install sqlite3
which will fail with the very exact message Ansible displayed.
The following playbook will escalate by default to the root user:
---
- name: Testing...
hosts: all
become: true
tasks:
- name: Just want to install sqlite3 for example...
apt: name=sqlite3 state=present

Answer 2

remote_user is david. Call the script with --ask-pass and give password for david. If david doesn't have passwordless sudo, then you should also call it with --ask-become-pass.
- name: Testing...
hosts: all
remote_user: david
become: true
become_method: sudo
tasks:
- name: Just want to install sqlite3 for example...
apt: name=sqlite3 state=present

Answer 3

I have the same issue.
The issue is solved by using root and --ask-become-pass --ask-pass command together.
- name: Testing...
hosts: all
remote_user: root
become: true
become_method: sudo
tasks:
- name: Just want to install sqlite3 for example...
apt: name=sqlite3 state=present
ansible-playbook playbook.yml --ask-become-pass --ask-pass