New Compute Node not Getting Mapped to Cells

asked 2020-01-14 09:16:09 -0500

anuroopd gravatar image

I'm trying to setup a small scale Openstack cluster. As a trail, I want to configure one compute node to launch my instances.

I have installed Openstack (Train) controller on one of my server and nova-compute service on a host on which I want to launch VMs.

After installing and following all the steps specified in this guide: (, compute nodes are not getting mapped into the required cell and there by controller is not list the compute node under 'hypervisor' list on Horizon.

In my setup:

controller ===>, running Ubunutu 18.04

compute node ===>, running Ubuntu 16.04


nova service-list --binary nova-compute

    | Id      | Binary       | Host                | Zone | Status  | State | Updated_at    | Disabled Reason | Forced down |

18a7c3df-5d8b-44d3-b660-a67ae7979e62 | nova-compute | | nova | enabled | up    | 2020-01-14T14:21:23.000000 | -               | False       |

2c44b1a3-209b-409f-a1e5-927adc20d9a0 | nova-compute | | nova | enabled | up    | 2020-01-14T14:21:18.000000 | -               | False       |

As show here, the nova-compute service running on the compute node i.e. r530-c1-001 is being listed but the hypervisor is not getting listed on hypervisor-list.

nova hypervisor-list

ID                                   | Hypervisor hostname | State | Status  |

| 235de530-3a37-4c86-b9c8-658bc9d7791b | | up    | enabled |

I think the reason for this is because, the compute node or compute host (r530-c1-001) is getting mapped to the nova_cell0 (which is a special cell) instead of the nova_cell1, even after running the ' su -s /bin/sh -c "nova-manage cell_v2 discover_hosts --verbose" '

To confirm the above hypothesis, I have looked into both nova_cell0 and nova_cell1 databases and more importantly the table compute_nodes. As expected, compute host is listed in nova_cell0:compute_nodes table and hypervisor on (controller) is listed on nova_cell1:compute_nodes.

Details of nova-cells:

nova-manage cell_v2 list_cells

|  Name |    UUID                 |        Transport URL          |         Database Connection  | Disabled |

| cell0 | 00000000-0000-0000-0000-000000000000 |    none:/  | mysql+pymysql://root:PASSW@ |  False  

| cell1 | 6670bef3-b90b-49cd-8da2-c7e571ae8b07 | rabbit://stackrabbit:PASSW@ | mysql+pymysql://root:PASSW@ |  False

Question 1: From the above output, is the format for transport_url of cell1 correct ?

Config files for controller is at: and compute node is at:

Question 2: Are the config file for both controller and compute node, correct ? Did I miss any vital information in config file ?

Question 3: Are the transport_url, [database]:connection and [api_data]:connection are of correct format in compute host config file.

Any help is much appreciated.

Thanks, Anuroop

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You are setting up a Train environment but use Pike instructions. Train is four releases after Pike. To be certain you do things correctly, use Train instructions.

Bernd Bausch gravatar imageBernd Bausch ( 2020-01-14 19:23:21 -0500 )edit

@Bernd, I understand that I maybe using wrong configuration. Can you please point out to the wrong configuration field in my config files for both controller and nova-compute ?

And also can you point me to the Train instructions document. All I could find is release notes of Train.


anuroopd gravatar imageanuroopd ( 2020-01-14 19:50:12 -0500 )edit

See Installation Guides on

Sorry, but I have never installed Train and don't want to spend time checking configuration settings that are based on Pike instructions. If you don't want to use Train documentation, look for error messages in the Nova log files.

Bernd Bausch gravatar imageBernd Bausch ( 2020-01-15 00:21:30 -0500 )edit

@Bernd, Thanks. I'm using devstack to setup my openstack on controller and it is writing those config files.

In my output for list_cells, the database connection for cell0 and cell1 are using, is this correct? Devstack is creating them and installation docs uses "@controller".

anuroopd gravatar imageanuroopd ( 2020-01-15 08:56:35 -0500 )edit