Commit ab775c25 authored by Christos Stavrakakis's avatar Christos Stavrakakis

Update admin-guide about RabbitMQ

parent 37c5ea1c
......@@ -236,7 +236,11 @@ Synnefo uses Google Ganeti backends for VM cluster management. In order Cyclades
to be able to handle thousand of user requests, Cyclades and Ganeti communicate
asynchronously. Briefly, requests are submitted to Ganeti, and asynchronous
notifications about the progress of jobs is received from the backends. The
architecture and communication with a Ganeti backend is shown in Figure?.
architecture and communication with a Ganeti backend is shown the below graph.
.. image:: images/cyclades-ganeti-communication.png
:width: 50%
:target: _images/cyclades-ganeti-communication.png
Cyclades API server is responsible for handling user requests. Read-only
requests are directly served by looking up the Cyclades DB. If the request
......@@ -263,21 +267,6 @@ Cyclades API, will retrieve the updated state from the DB.
Prereqs
-------
RabbitMQ
~~~~~~~~
RabbitMQ is used as a generic message broker for Cyclades. It should be
installed on two seperate :ref:`QUEUE <QUEUE_NODE>` nodes in a high
availability configuration as described here:
http://www.rabbitmq.com/pacemaker.html
The values set for the user and password must be mirrored in the ``RABBIT_*``
variables in your settings, as managed by :ref:`snf-common <snf-common>`.
.. todo:: Document an active-active configuration based on the latest version
of RabbitMQ.
Installation
------------
......@@ -498,21 +487,6 @@ Archipelago advanced operations
-------------------------------
.. _mail-server:
Configure mail server
---------------------
In order to be able to send email (for example activation emails),
synnefo needs access to a running mail server. Your mail server should
be defined in the ``/etc/synnefo/00-snf-common-admins.conf``
related constants. At least:
.. code-block:: console
EMAIL_HOST = "my_mail_server.example.com"
EMAIL_PORT = "25"
The "kamaki" API client
=======================
......@@ -594,6 +568,91 @@ To verify that the image was registered successfully use:
Miscellaneous
=============
.. RabbitMQ
RabbitMQ Broker
---------------
Queue nodes run the RabbitMQ sofware, which provides AMQP functionality. To
guarantee high-availability, more than one Queue nodes should be deployed, each
of them belonging to the same `RabbitMQ cluster
<http://www.rabbitmq.com/clustering.html>`_. Synnefo uses RabbitMQ
active/active `High Available Queues <http://www.rabbitmq.com/ha.html>`_ that
are mirrored on nodes within a RabbitMQ cluster.
The RabbitMQ nodes that form the cluster, are declared to Synnefo through
the `AMQP_HOSTS` setting. Each time a Synnefo component needs to connect
RabbitMQ, one of this nodes is chosen in a random way. The client that
synnefo uses to connect with RabbitMQ, silently handles connection failures
and tries to reconnect to a different node. As long as one of these nodes
are up and running, functionality of synnefo should no be downgraded by
RabbitMQ node failures.
All the queues that are being used are declared as durable, meaning that
messages are persistently stored to RabbitMQ until are successfully processed
by a client.
Currently, RabbitMQ is used by the following components:
* snf-ganeti-eventd, snf-ganeti-hook and snf-progress-monitor:
These components send messages concerning the status and progress of
jobs in the Ganeti backend.
* snf-dispatcher: This daemon, consumes the messages that are send from
the above components, and updates the Cyclades DB.
Installation
````````````
Please check RabbitMQ documentation which covers extensively the `installation
of RabbitMQ server <http://www.rabbitmq.com/download.html>`_ and the setup of a
`RabbitMQ cluster <http://www.rabbitmq.com/clustering.html>`_. Also, check out
the `web management plugin <http://www.rabbitmq.com/management.html>`_ that can
be useful for managing and monitoring RabbitMQ.
For a basic installation of RabbitMQ on two nodes (node1 and node2) you can do
the follow steps:
On both nodes, install rabbitmq-server and create a synnefo user:
.. code-block:: console
$ apt-get install rabbitmq-server
$ rabbitmqctl add_user synnefo "example_pass"
$ rabbitmqctl set_permissions synnefo ".*" ".*" ".*"
Also guarantee that two nodes share the same cookie, by running
.. code-block:: console
$ scp node1:/var/lib/rabbitmq/.erlang.cookie node2:/var/lib/rabbitmq/.erlang.cookie
and restart the nodes:
.. code-block:: console
$ /etc/init.d/rabbitmq-server restart
To setup the RabbitMQ cluster run:
.. code-block:: console
root@node2: rabbitmqctl stop_app
root@node2: rabbitmqctl reset
root@node2: rabbitmqctl cluster rabbit@node1 rabbit@node2
root@node2: rabbitmqctl start_app
You can verify that the cluster is set up correctly by running:
.. code-block:: console
root@node2: rabbitmqctl cluster_status
Admin tool: snf-manage
----------------------
......
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