openstack/deb-sahara
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Added documentation for Designate feature

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Change-Id: I0a9d7ffd8aaea904bf99ab0669fe2c5cf1264ba5
partial-bp: designate-integration
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Michael Ionkin
2016-08-03 14:12:16 +03:00
parent 6039058e1b
commit 124abc1954
1 changed files with 53 additions and 0 deletions
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doc/source/userdoc/advanced.configuration.guide.rst
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@@ -40,6 +40,59 @@ a custom network namespace:
[DEFAULT]
proxy_command='ip netns exec ns_for_{network_id} nc {host} {port}'
.. _dns_hostname_resolution:
DNS Hostname Resolution
-----------------------
Sahara can resolve hostnames of cluster instances by using DNS. For this Sahara
uses Designate. With this feature, for each instance of the cluster Sahara will
create two ``A`` records (for internal and external ips) under one hostname
and one ``PTR`` record. Also all links in the Sahara dashboard will be
displayed as hostnames instead of just ip addresses.
You should configure DNS server with Designate. Designate service should be
properly installed and registered in Keystone catalog. The detailed
instructions about Designate configuration can be found here: `Designate manual
installation`_ and here: `Configuring OpenStack Networking with Designate`_.
Also if you use devstack you can just enable Designate plugin:
`Designate devstack`_.
When Designate is configured you should create domain(s) for hostname
resolution. This can be done by using the Designate dashboard or by CLI. Also
you have to create ``in-addr.arpa.`` domain for reverse hostname resolution
because some plugins (e.g. ``HDP``) determine hostname by ip.
Sahara also should be properly configured. In ``sahara.conf`` you must specify
two config properties:
.. sourcecode:: cfg
[DEFAULT]
# Use Designate for internal and external hostnames resolution:
use_designate=true
# IP addresses of Designate nameservers:
nameservers=1.1.1.1,2.2.2.2
An OpenStack operator should properly configure the network. It must enable
DHCP and specify DNS server ip addresses (e.g. 1.1.1.1 and 2.2.2.2) in
``DNS Name Servers`` field in the ``Subnet Details``. If the subnet already
exists and changing it or creating new one is impossible then Sahara will
manually change ``/etc/resolv.conf`` file on every instance of the cluster (if
``nameservers`` list have been specified in ``sahara.conf``). In this case,
though, Sahara cannot guarantee that these changes will not be overwritten by
DHCP or other services of the existing network. Sahara has a health check for
track this situation (and if it occurs the health status will be red).
In order to resolve hostnames from your local machine you should properly
change your ``/etc/resolv.conf`` file by adding appropriate ip addresses of
DNS servers (e.g. 1.1.1.1 and 2.2.2.2). Also the VMs with DNS servers should
be available from your local machine.
.. _Designate manual installation: http://docs.openstack.org/developer/designate/install/ubuntu-liberty.html
.. _Configuring OpenStack Networking with Designate: http://docs.openstack.org/mitaka/networking-guide/adv-config-dns.html#configuring-openstack-networking-for-integration-with-an-external-dns-service
.. _Designate devstack: http://docs.openstack.org/developer/designate/devstack.html
.. _data_locality_configuration:
Data-locality configuration