[openstack-dev] [stable/ocata] [nova] [devstack multi-node] nova-conductor complaining about "No cell mapping found for cell0"

Matt Riedemann mriedemos at gmail.com
Wed Feb 22 12:14:25 UTC 2017


On 2/21/2017 10:38 AM, Prashant Shetty wrote:
> Hi Mark,
>
> Thanks for your reply.
>
> I tried "nova-manage cell_v2 discover_hosts" and it returned nothing and
> still I have same issue on the node.
>
> Problem seems be the way devstack is getting configured,
> As code suggest below we create cell0 on node where n-api and n-cpu
> runs. In my case compute is running only n-cpu and controller is running
> n-api service, due to this code there are no cell created in controller
> or compute.

The nova_cell0 database is created here:

https://github.com/openstack-dev/devstack/blob/7a30c7fcabac1cf28fd9baa39d05436680616aef/lib/nova#L680

That's the same place that the nova_api database is created.

>
> We will not have this  problem in all-in-one-node setup.
> --
> # Do this late because it requires compute hosts to have started
> if is_service_enabled n-api; then
>     if is_service_enabled n-cpu; then
>         create_cell
>     else
>         # Some CI systems like Hyper-V build the control plane on
>         # Linux, and join in non Linux Computes after setup. This
>         # allows them to delay the processing until after their whole
>         # environment is up.
>         echo_summary "SKIPPING Cell setup because n-cpu is not enabled.
> You will have to do this manually before you have a working environment."
>     fi
> fi

You're correct that when stacking the control node where n-api is 
running, you won't get to the create_cell call:

https://github.com/openstack-dev/devstack/blob/7a30c7fcabac1cf28fd9baa39d05436680616aef/stack.sh#L1371

The create_cell function is what creates the cell0 mapping in the 
nova_api database and runs the simple_cell_setup command:

https://github.com/openstack-dev/devstack/blob/7a30c7fcabac1cf28fd9baa39d05436680616aef/lib/nova#L943

You're running discover_hosts from the control node where the nova_api 
database lives, so that looks correct.

Can you run discover_hosts with the --verbose option to get some more 
details, i.e. how many cell mappings are there, how many host mappings 
and compute_nodes records are created?

I think the issue is that you haven't run map_cell0 and 
simple_cell_setup. In the gating multinode CI job, the create_cell 
function in devstack is called because that's a 2-node job where n-cpu 
is running on both nodes, but n-api is only running on the control 
(primary) node. In your case you don't have that so you're going to have 
to run these command manually.

The docs here explain how to set this up and the commands to run:

https://docs.openstack.org/developer/nova/cells.html#setup-of-cells-v2
https://docs.openstack.org/developer/nova/cells.html#fresh-install

> ---
>
> vmware at cntr11:~$ nova-manage cell_v2 discover_hosts
> vmware at cntr11:~$ nova service-list
> +----+------------------+---------------+----------+---------+-------+----------------------------+-----------------+
> | Id | Binary           | Host          | Zone     | Status  | State |
> Updated_at                 | Disabled Reason |
> +----+------------------+---------------+----------+---------+-------+----------------------------+-----------------+
> | 3  | nova-conductor   | cntr11        | internal | enabled | up    |
> 2017-02-21T15:34:13.000000 | -               |
> | 5  | nova-scheduler   | cntr11        | internal | enabled | up    |
> 2017-02-21T15:34:15.000000 | -               |
> | 6  | nova-consoleauth | cntr11        | internal | enabled | up    |
> 2017-02-21T15:34:11.000000 | -               |
> | 7  | nova-compute     | esx-ubuntu-02 | nova     | enabled | up    |
> 2017-02-21T15:34:14.000000 | -               |
> | 8  | nova-compute     | esx-ubuntu-03 | nova     | enabled | up    |
> 2017-02-21T15:34:16.000000 | -               |
> | 9  | nova-compute     | kvm-3         | nova     | enabled | up    |
> 2017-02-21T15:34:07.000000 | -               |
> | 10 | nova-compute     | kvm-2         | nova     | enabled | up    |
> 2017-02-21T15:34:13.000000 | -               |
> | 11 | nova-compute     | esx-ubuntu-01 | nova     | enabled | up    |
> 2017-02-21T15:34:14.000000 | -               |
> | 12 | nova-compute     | kvm-1         | nova     | enabled | up    |
> 2017-02-21T15:34:09.000000 | -               |
> +----+------------------+---------------+----------+---------+-------+----------------------------+-----------------+
> vmware at cntr11:~$
> vmware at cntr11:~$ nova-manage cell_v2 list_cells
> +------+------+
> | Name | UUID |
> +------+------+
> +------+------+
> vmware at cntr11:~$
>
>
> Thanks,
> Prashant
>

-- 

Thanks,

Matt Riedemann



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