Node Configuration

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.

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