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##### SUMMARY
<!--- Explain the problem briefly below -->
Ansible currently contains two modules for managing AWS EC2 instances: [`ec2`](https://docs.ansible.com/ansible/latest/modules/ec2_module.html) and [`ec2_instance`](https://docs.ansible.com/ansible/latest/modules/ec2_instance_module.html).

There is considerable overlap between the modules, but it's unclear what the differences are and why there are two modules in the first place.

##### ISSUE TYPE
- Documentation Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
ec2
ec2_instance

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
ansible 2.10.0.dev0
  config file = /home/user/.ansible.cfg
  configured module search path = ['/home/user/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/user/ansible/lib/ansible
  executable location = /home/user/ansible/bin/ansible
  python version = 3.7.5 (default, Oct 27 2019, 15:43:29) [GCC 9.2.1 20191022]
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below
RETRY_FILES_ENABLED(/home/user/.ansible.cfg) = False
```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
Debian bullseye/sid

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->

<!--- Paste example playbooks or commands between quotes below -->
```yaml
N/A
```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
N/A

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->

<!--- Paste verbatim command output between quotes -->
```paste below
N/A
```

if volumes:
                bdm = BlockDeviceMapping()
                for volume in volumes:
                    if 'device_name' not in volume:
                        module.fail_json(msg='Device name must be set for volume')
                    
                    
                    if 'volume_size' not in volume or int(volume['volume_size']) > 0:
                        bdm[volume['device_name']] = create_block_device(module, ec2, volume)
                params['block_device_map'] = bdm
            
            if not spot_price:
                if assign_public_ip is not None and private_ip:
                    params.update(
                        dict(
                            min_count=count_remaining,
                            max_count=count_remaining,
                            client_token=id,
                            placement_group=placement_group,
                        )
                    )
                else:
                    params.update(
                        dict(
                            min_count=count_remaining,
                            max_count=count_remaining,
                            client_token=id,
                            placement_group=placement_group,
                            private_ip_address=private_ip,
                        )