nik-redhat / odincontrol

A lightweight remote command executor

odinControl

A remote command executor

Why do we need a remote command executor

Well it's an age old requirement. You have X servers and you want to configure them all without actually going over to each of those servers and doing the operation again and again.

One could leverage BASH for doing the same ? Well technically you can. Create a bash script, then leverage the use of ssh to remotely execute that BASH script across the servers. ( Actually sounds like a challenge, maybe one should take a look into it..). But then comes the question of user friendliness.

Is odinControl user friendly? You tell me. If it isn't, maybe the best way is to either open a BUG or request some new feature.

Usage

One can create an object of Rexe,

rc_handle = Rexe(<path_of_conf_file>, <exec_file_path>) # <exec_file_path> is optional

Once the object has been created, connection has to be established to the remote servers before any operation is undertaken.

rc_handle.establish_connection()

To execute any command, one can either use the function execute_command or execute_command_multinode The difference being execute_command only executes a given command in one node while the latter does it in a given list of nodes.

To obtain the list of nodes which were parsed from the config file, one could use the instance variable conf_data['host_list']

For example if somebody had to execute a command ls /home on the first node in the given list of hosts,

ret = rc_handle.execute_command(rc_handle.conf_data['host_list'][1], 'ls /home')

Now the return value will be of the following format,

{
  'Flag' : True/False,
  'node' : "the node for which the command was run",
  'cmd' : "the command which was requested",
  'error_code' : BASH error code in integer
  'msg' : "The return value in form of dictionary for glusterfs commands or string for other commands"
}

In case of multinode command execution, the result will be a list of result dictionaries of all the nodes so if we have ret', ret2, ret3 then the return value of execute_command_multinode will be [ret1, ret2, ret3]