detect_arista_eos raises exception against unix host

[tyler-ball]

Train version 0.21.0. Original stacktrace:

tball@delivery-server-acceptance:~$ sudo delivery-ctl install-runner -I /etc/delivery/chefdk-el7.rpm -f hostname --username ubuntu -i /etc/delivery/runners.pem -a tball -t 'token' -o -P none

Connecting to runner-acceptance-ubuntu1404-v2-1.builders-acceptance.shd.chef.co...
 (JSON::ParserError)ed/lib/ruby/gems/2.2.0/gems/json-2.0.2/lib/json/common.rb:156:in `parse': 743: unexpected token at 'bash: show: command not found
bash: json: command not found
'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/json-2.0.2/lib/json/common.rb:156:in `parse'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/extras/os_detect_arista_eos.rb:20:in `detect_arista_eos'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/extras/os_common.rb:127:in `detect_family_type'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/extras/os_common.rb:89:in `detect_family'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/extras/os_common.rb:31:in `initialize'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh_connection.rb:233:in `initialize'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh_connection.rb:58:in `new'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh_connection.rb:58:in `os'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/extras/command_wrapper.rb:165:in `load'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh_connection.rb:45:in `initialize'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh.rb:155:in `new'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh.rb:155:in `create_new_connection'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh.rb:75:in `connection'
	from /opt/delivery/embedded/service/omnibus-ctl/runner/remote_connection.rb:19:in `connect!'
	from /opt/delivery/embedded/service/omnibus-ctl/runner/installer.rb:49:in `install'
	from (eval):10:in `block in load_file'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/omnibus-ctl-0.3.6/lib/omnibus-ctl.rb:171:in `call'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/omnibus-ctl-0.3.6/lib/omnibus-ctl.rb:171:in `block in add_command'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/omnibus-ctl-0.3.6/lib/omnibus-ctl.rb:575:in `run'
	from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/omnibus-ctl-0.3.6/bin/omnibus-ctl:31:in `<top (required)>'
	from /opt/delivery/embedded/bin/omnibus-ctl:23:in `load'
	from /opt/delivery/embedded/bin/omnibus-ctl:23:in `<main>'

I have tried trying to access both an Ubuntu and Centos node using a Train connection.

connect_options => {:host=>"runner-acceptance-ubuntu1404-v2-1.builders-acceptance.shd.chef.co",
 :port=>22,
 :user=>"ubuntu",
 :key_files=>"/etc/delivery/runners.pem",
 :logger=>
  #<Logger:0x00000001b481c8
   @default_formatter=#<Logger::Formatter:0x00000001b481a0 @datetime_format=nil>,
   @formatter=nil,
   @level=0,
   @logdev=
    #<Logger::LogDevice:0x00000001b48150
     @dev=#<File:/var/log/delivery-ctl/runner-install_runner-acceptance-ubuntu1404-v2-1.builders-acceptance.shd.chef.co.log>,
     @filename="/var/log/delivery-ctl/runner-install_runner-acceptance-ubuntu1404-v2-1.builders-acceptance.shd.chef.co.log",
     @mutex=#<Logger::LogDevice::LogDeviceMutex:0x00000001b48128 @mon_count=0, @mon_mutex=#<Mutex:0x00000001b480d8>, @mon_owner=nil>,
     @shift_age=0,
     @shift_size=1048576>,
   @progname=nil>,
 :pty=>true,
 :sudo=>true,
 :sudo_password=>"none"}
@train = Train.create('ssh', connect_options)
@train.connection # fails

[tyler-ball]

Adding pry debug points in os_common I can see that detect_linux returns true, but it is detect_arista_eos that fails. Looks like it is this line that is failing: https://github.com/chef/train/blob/master/lib/train/extras/os_detect_arista_eos.rb#L16

When I log into that host and try to run /bin/bash -c 'show version | json' I get:

ubuntu@ip-10-194-11-235:~$ /bin/bash -c 'show version | json'
/bin/bash: show: command not found
/bin/bash: json: command not found

[chris-rock]

I have a feeling why this happens. Not sure why this is not happening on my system though

[chris-rock]

@tyler-ball Could you find out the result of https://github.com/chef/train/blob/master/lib/train/extras/os_detect_arista_eos.rb#L16
If the commands are not available, stdout should be empty, so the json should never be parsed

[tyler-ball]

[1] pry(#<Train::Transports::SSH::Connection::OS>)> output
=> "bash: show: command not found\r\nbash: json: command not found\r\n"

[chris-rock]

Why is the stderr piped into stdout?

[tyler-ball]

Looks like it is piped to stdout because we enabled the PTY. Disabling the PTY in the connection settings results in

/opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/extras/command_wrapper.rb:169:in `load': Sudo failed: Sudo requires a TTY. Please see the README on how to configure sudo to allow for non-interactive usage. (Train::UserError)
from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh_connection.rb:45:in `initialize'
from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh.rb:155:in `new'
from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh.rb:155:in `create_new_connection'
from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/train-0.21.0/lib/train/transports/ssh.rb:75:in `connection'
from /opt/delivery/embedded/service/omnibus-ctl/runner/remote_connection.rb:19:in `connect!'
from /opt/delivery/embedded/service/omnibus-ctl/runner/installer.rb:49:in `install'
from (eval):10:in `block in load_file'
from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/omnibus-ctl-0.3.6/lib/omnibus-ctl.rb:171:in `call'
from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/omnibus-ctl-0.3.6/lib/omnibus-ctl.rb:171:in `block in add_command'
from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/omnibus-ctl-0.3.6/lib/omnibus-ctl.rb:575:in `run'
from /opt/delivery/embedded/lib/ruby/gems/2.2.0/gems/omnibus-ctl-0.3.6/bin/omnibus-ctl:31:in `<top (required)>'
from /opt/delivery/embedded/bin/omnibus-ctl:23:in `load'
from /opt/delivery/embedded/bin/omnibus-ctl:23:in `<main>'