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19.04 release note for ncc memcached spaces bug 

Change-Id: I9a19e5ff84ef6795ad7f34fedeb95dcb7c43e61c
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David Ames 2019-04-15 15:25:11 -07:00 committed by James Page
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@ -218,9 +218,46 @@ If the charm is running in an HA deployment, a relation to memcached must be add
juju add-relation nova-cloud-controller memcached
.. warning::
See known issues below: Adding nova-cloud-controller memcached relation
Known Issues
============
Adding nova-cloud-controller memcached relation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. warning::
If a memcached application already exists in the model it is possible that the
nova-cloud-controller and memcached applications have different default spaces
or the cache relation is not bound to a matching network space.
This leads to `bug 1823740`_ where memcached units have the wrong IP addresses
for the nova-cloud-controller units in the iptables rules used to restrict access.
The symptom is the command "openstack availability zone" list timing out and SYN_SENT connections on the nova-cloud-controller unit to the memcached unit. Launching new instances will also fail.
Because Juju does not currently allow network space binding post-deployment (`bug 1796653`_) memcached must be (re-)deployed with the correct network space bindings to support access from the nova-cloud-controller units.
There are two approaches. The safest of which is to deploy a new set of memcached units either with their cache relationship bound to nova-cloud-controllers default space or their default space set to the same as nova-cloud-controllers.
.. code:: bash
juju deploy -n 2 cs:memcached --to lxd:1,lxd:2 --bind "cache=<NCC's DEFAULT SPACE>" ncc-memcached
or
.. code:: bash
juju deploy -n 2 cs:memcached --to lxd:1,lxd:2 --bind "<NCC's DEFAULT SPACE>" ncc-memcached
The alternative is to remove the existing memcached application entirely and redeploy it using the same approach.
.. _bug 1823740: https://bugs.launchpad.net/charm-nova-cloud-controller/+bug/1823740
.. _bug 1796653: https://bugs.launchpad.net/juju/+bug/1796653
Bugs Fixed
==========