Node Configuration

Node Configuration

This section explains the various ways a user can configure nodes.

Libvirt Node Configuration

You configure the overcloud nodes by placing variable definitions in a YAML file and passing that to ansible using the -N command line option, like this:

quickstart.sh -N config/nodes/1ctlr_1comp.yml

Setting number and type of overcloud nodes

The overcloud_nodes variable can be used to change the number and type of nodes deployed in your overcloud. The default (config/general_config/minimal.yml) looks like this:

overcloud_nodes:
  - name: control_0
    flavor: control
    virtualbmc_port: 6230

  - name: compute_0
    flavor: compute
    virtualbmc_port: 6231

You can use your own config if you want to test a different setup. For example:

overcloud_nodes:
  - name: control_0
    flavor: control
    virtualbmc_port: 6230
  - name: control_1
    flavor: control
    virtualbmc_port: 6231
  - name: control_2
    flavor: control
    virtualbmc_port: 6232

  - name: compute_0
    flavor: compute
    virtualbmc_port: 6233

  - name: ceph_0
    flavor: ceph
    virtualbmc_port: 6234

  - name: swift_0
    flavor: objectstorage
    virtualbmc_port: 6235

Controlling resources

These variables set the resources that will be assigned to a node by default, unless overridden by a more specific variable:

  • default_disk
  • default_memory
  • default_vcpu

These variables set the resources assigned to the undercloud node:

  • undercloud_disk
  • undercloud_memory (defaults to 12288)
  • undercloud_vcpu (defaults to 4)

These variables set the resources assigned to controller nodes:

  • control_disk
  • control_memory
  • control_vcpu

These variables control the resources assigned to compute nodes:

  • compute_disk
  • compute_memory
  • compute_vcpu

These variables control the resources assigned to ceph storage nodes:

  • ceph_disk
  • ceph_memory
  • ceph_vcpu

There is another option extradisks that can be used to create three additional blockdevices vdb, vdc and vdd per node. By default it is only enabled on the objectstorage node flavor. Note that ironic will pick the smallest disk available in the node when there are multiple disks attached. You must either set the same size to all the disks using extradisks_size or provide root_device_hints to set in ironic.

An example

To create a minimal environment that would be unsuitable for deploying anything real nova instances, you could place something like the following in myconfigfile.yml:

undercloud_memory: 8192
control_memory: 6000
compute_memory: 2048

overcloud_nodes:
  - name: control_0
    flavor: control
    virtualbmc_port: 6230

  - name: compute_0
    flavor: compute
    virtualbmc_port: 6231

And then pass that to the ansible-playbook command as described at the beginning of this document.

Baremetal Node Configuration

Baremetal deployments are unique from libvirt virtual deployments in that the hardware, the specs, and network settings can not be adjusted via a configuration file. These settings for each individual baremetal deployment are unique and must be stored separately.

What the baremetal node configuration baremetal.yml does is essentially ensuring that no libvirt guests are provisioned setting overcloud_nodes to null:

overcloud_nodes:

The pattern and layout for baremetal hardware configuration can be found in this doc

For additional support with baremetal deployments please visit the #oooq channel on freenode irc.

OpenStack Virtual Baremetal Node Configuration

Using OpenStack Virtual Baremetal is a simple node configuration where the user needs only to define how many cloud instances to run.

For example, you will find the following config in the node configuration files:

# Define the controller node and compute nodes.
# Create three controller nodes and one compute node.
node_count: 4

The remaining configuration for the instances like the flavor types are found in the config/environment/ configuration as this may vary based on your cloud provider. For an example please reference this configuration

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