Synnefo » snf-ganeti

Once a node's SSH daemon has been configured, more than 25 files need to

be copied using ``scp`` before the node daemon can be started. No

verification is being done before files are copied. Once the node daemon

is started, an opcode is submitted to the master daemon, which will then

copy more files, such as the configuration and job queue for master

candidates, using RPC. This process is somewhat fragile and requires

initiating many SSH connections.

SSH

~~~

Node daemon

~~~~~~~~~~~

Similar to SSH setup changes, the process of copying files and starting

the node daemon will be moved into a dedicated program. On its standard

input it will receive a standardized JSON structure (defined :ref:`below

<node-daemon-setup-json>`). Once the input data has been successfully

decoded and the received values were verified for sanity, the program

proceeds to write the values to files and then starts the node daemon

(``ganeti-noded``).

To add a new node to the cluster, the master node will have to gather

all values, build the data structure, and then invoke the newly added

``node-daemon-setup`` program via SSH. In this way only a single SSH

connection is needed and the values can be verified before being written

to files.

If the program exits successfully, the node is ready to be added to the

master daemon's configuration. The node daemon will be running, but

``OpNodeAdd`` needs to be run before it becomes a full node. The opcode

will copy more files, such as the :doc:`RAPI certificate <rapi>`.

Data structures

---------------

JSON structure for SSH setup

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. _node-daemon-setup-json:

JSON structure for node daemon setup

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The data is given in an object containing the keys described below.

Unless specified otherwise, all entries are optional.

``cluster_name``

  Required string with the cluster name. If a local cluster name is

  found, the join process is aborted unless the passed cluster name

  matches the local name. The cluster name is also included in the

  dictionary given via the ``ssconf`` entry.

``node_daemon_certificate``

  Public and private part of cluster's node daemon certificate in PEM

  format. If a local node certificate is found, the process is aborted

  unless it matches.

``ssconf``

  Dictionary with ssconf names and their values. Both are strings.

  Example:

  .. highlight:: javascript

  ::

    {

      "cluster_name": "cluster.example.com",

      "master_ip": "192.168.2.1",

      "master_netdev": "br0",

      # …

    }

``start_node_daemon``

  Boolean denoting whether the node daemon should be started (or

  restarted if it was running for some reason).