Validation should catch unavailable resources

[Steven Hardy]

If you try to launch a stack containing, e.g a OS::Neutron resource on an openstack which doesn't have Neutron, we fail to catch that during validation and start the stack create, then fail later.

It would be better if we could validate availability of the resources (by checking the client can be instantiated, this the endpoint is found?) such that we fail fast when a service is not available.

Possibly, we could add a test to the resource superclass which tries to instantiate the resource client?

[Pavlo Shchelokovskyy (pshchelo)]

Once I had an idea of detecting if Neutron is available during heat-engine start and simply not to register Neutron resources then (so they do not even show up in heat resource-type-list), but it turns out some deployments like TripleO do start heat before Neutron...

Also, especially for Nova-network/Neutron case, we have some resources that are "transparent" and use several clients, so there is no single "resource client".

[Steven Hardy (shardy)]

Yeah, I think it has to be done per-stack at runtime, based on the content of the keystone catalog, which is not perfect as it doesn't prove the service is running, but it does at least prove it's configured and expected to be available in the environment heat is running - this to me seems the least expensive pre-create check we can do, but open to other ideas :)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/132305

[Steve Baker (steve-stevebaker)]

On 31/10/14 14:55, Pavlo Shchelokovskyy wrote:
> Once I had an idea of detecting if Neutron is available during heat-
> engine start and simply not to register Neutron resources then (so they
> do not even show up in heat resource-type-list), but it turns out some
> deployments like TripleO do start heat before Neutron...
They start heat before keystone too ;)

Calling self.client_plugin('<client name>') would be enough to determine
if a service is available, and will be cheap to do during validation
since it is just looking up an already loaded service catalog.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Tetiana Lashchova (<email address hidden>) on branch: master
Review: https://review.openstack.org/132305

[Zane Bitter (zaneb)]

Fix was https://git.openstack.org/cgit/openstack/heat/commit?id=490c36f7d0715ba72f04e1898ccb41b5fac81e83