Shared connection to server closed - ssh

Question

When I run this:
$ ansible -i s1, s1 -m raw -a 'echo test' -u root -k
I get:
s1 | SUCCESS | rc=0 >>
test
Shared connection to s1 closed.
But this way:
$ ansible -i s1, s1 -m command -a 'echo test' -u root -k
I don't get "Shared connection to s1 closed." part:
s1 | SUCCESS | rc=0 >>
test
Why is that?
P.S. Above is a simplified way to reproduce the issue. What I'm facing is that when running playbook I get this extra line which is in the way.
UPD The line clearly coming from ssh. And if I run raw command with -vvvv, I get:
Using /etc/ansible/ansible.cfg as config file
Loading callback plugin minimal of type stdout, v2.0 from /usr/lib/python2.7/site-packages/ansible/plugins/callback/__init__.pyc
<s1> ESTABLISH SSH CONNECTION FOR USER: root
<s1> SSH: EXEC sshpass -d13 ssh -vvv -C -o ControlMaster=auto
-o ControlPersist=60s -o User=root -o ConnectTimeout=10
-o ControlPath=/home/yuri/.ansible/cp/ansible-ssh-%h-%p-%r -tt s1
'echo test'
s1 | SUCCESS | rc=0 >>
test
OpenSSH_7.4p1, OpenSSL 1.0.2k 26 Jan 2017
debug1: Reading configuration data /home/yuri/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: auto-mux: Trying existing master
debug1: Control socket "/home/yuri/.ansible/cp/ansible-ssh-s1-22-root" does not exist
<...a lot of output from ssh...>
But with command, it's just:
Using /etc/ansible/ansible.cfg as config file
Loading callback plugin minimal of type stdout, v2.0 from
/usr/lib/python2.7/site-packages/ansible/plugins/callback/__init__.pyc
Using module file
/usr/lib/python2.7/site-packages/ansible/modules/core/commands/command.py
<s1> ESTABLISH SSH CONNECTION FOR USER: root
<s1> SSH: EXEC sshpass -d13 ssh -vvv -C -o ControlMaster=auto
-o ControlPersist=60s -o User=root -o ConnectTimeout=10
-o ControlPath=/home/yuri/.ansible/cp/ansible-ssh-%h-%p-%r s1
'/bin/sh -c '"'"'(
umask 77
&& mkdir -p "` echo ~/.ansible/tmp/ansible-tmp-1488989540.6-73006073289737 `"
&& echo ansible-tmp-1488989540.6-73006073289737="` echo ~/.ansible/tmp/ansible-tmp-1488989540.6-73006073289737 `"
) && sleep 0'"'"''
<s1> PUT /tmp/tmpes82wL TO
/root/.ansible/tmp/ansible-tmp-1488989540.6-73006073289737/command.py
<s1> SSH: EXEC sshpass -d13 sftp -o BatchMode=no -b - -vvv -C
-o ControlMaster=auto -o ControlPersist=60s -o User=root
-o ConnectTimeout=10
-o ControlPath=/home/yuri/.ansible/cp/ansible-ssh-%h-%p-%r '[s1]'
<s1> ESTABLISH SSH CONNECTION FOR USER: root
<s1> SSH: EXEC sshpass -d13 ssh -vvv -C -o ControlMaster=auto
-o ControlPersist=60s -o User=root -o ConnectTimeout=10
-o ControlPath=/home/yuri/.ansible/cp/ansible-ssh-%h-%p-%r s1
'/bin/sh -c '"'"'
chmod u+x /root/.ansible/tmp/ansible-tmp-1488989540.6-73006073289737/ /root/.ansible/tmp/ansible-tmp-1488989540.6-73006073289737/command.py
&& sleep 0'"'"''
<s1> ESTABLISH SSH CONNECTION FOR USER: root
<s1> SSH: EXEC sshpass -d13 ssh -vvv -C -o ControlMaster=auto
-o ControlPersist=60s -o User=root -o ConnectTimeout=10
-o ControlPath=/home/yuri/.ansible/cp/ansible-ssh-%h-%p-%r -tt s1
'/bin/sh -c '"'"'
/usr/bin/python /root/.ansible/tmp/ansible-tmp-1488989540.6-73006073289737/command.py;
rm -rf "/root/.ansible/tmp/ansible-tmp-1488989540.6-73006073289737/" > /dev/null 2>&1
&& sleep 0'"'"''
s1 | SUCCESS | rc=0 >>
test
Where is all ssh output gone?

Answer 1

Shared connection to s1 closed.
This message is an error message from ssh client.
With raw: echo test Ansible executes ssh <many parameters> s1 'echo test' and you get stdout/stderr from ssh command. This way message about shared connection pops up in your task result.
With command: echo test Ansible copy python-wrapper (command.py) and execute this wrapper, which in turn spawns echo test and capture stdout/stderr from echo commmand. Then command.py prints echo's result as JSON-object with stdout/stderr/rc keys. The ssh error message still occurs, but you don't see it (it is filtered by Ansible), because Ansible get task result from JSON-object key's and not from ssh plain stdout/stderr/rc.
Where is all ssh output gone?
This is related due to the same difference in handling raw/command. To see detailed ssh output set ANSIBLE_DEBUG=1 environment variable.
If you want to hide this error message, you can use ansible_ssh_extra_args='-o LogLevel=QUIET' inventory variable. But I'm not sure if this can give some other unexpected results.