Splitting the Overcloud stack into multiple independent Heat stacks¶
Since victoria TripleO provisions baremetal using a separate workflow Provisioning Baremetal Before Overcloud Deploy that does not involve Heat stack, making this feature irrelevant.
split-stack is a feature in TripleO that splits the overcloud stack into multiple independent stacks in Heat.
overcloud stack is split into an
overcloud-services stack. This allows for independent and isolated
management of the baremetal and services part of the Overcloud deployment. It
is a more modular design than deploying a single
overcloud stack in that it
allows either the baremetal or services stack to be replaced by tooling that is
external to TripleO if desired.
overcloud-services stack makes extensive use of the deployed-server
feature, documented at Using Already Deployed Servers in order to orchestrate the
deployment and configuration of the services separate from the baremetal
split-stack allows for mixing baremetal systems deployed by TripleO and those deployed by external tooling when creating the services stack. Since the baremetal resources are completely abstracted behind the deployed-server interface when deploying the services stack, it does not matter whether the servers were actually created with TripleO or not.
A default split-stack deployment (detailed in the later steps) can be deployed without any special requirements.
More advanced deployments where baremetal servers provisioned by TripleO will be mixed with those not provisioned by TripleO will want to pay attention to the requirements around using already deployed servers from Using Already Deployed Servers. The requirements for using deployed servers will apply when not using servers provisioned by TripleO.
Default split-stack deployment¶
split-stack will be deployed by running 2 separate
deploy commands to deploy the separate stacks.
If applicable, prepare the custom roles files and any custom environments
initially. The custom roles file and an environment setting the role counts
should be passed to both deployment commands so that enough baremetal nodes are
deployed per what the
overcloud-services stack expects.
Baremetal Deployment Command¶
Run the deployment command to deploy the
An additional environment file,
overcloud-baremetal.yaml, is passed to the
deployment to enable deploying just the baremetal stack.
Enough baremetal nodes should be deployed to match how many nodes per role will be needed when the services stack is deployed later. Be sure that the environment file being used to set the role counts is passed to the baremetal deployment command:
openstack overcloud deploy \ <other cli arguments> \ --stack overcloud-baremetal \ -r roles-data.yaml \ -e /usr/share/openstack-tripleo-heat-templates/environments/overcloud-baremetal.yaml \ -e /usr/share/openstack-tripleo-heat-templates/environments/split-stack-consistent-hostname-format.yaml
--stack argument sets the name of the Heat stack to
overcloud-baremetal. This will also be the name of the Swift container that
stores the stack’s plan (templates) and of the Mistral environment.
roles-data.yaml roles file illustrates passing a custom roles file to
the deployment command. It is not necessary to use custom roles when using
split stack, however if custom roles are used, the same roles file should be
used for both stacks.
overcloud-baremetal.yaml environment will set the parameters for the
deployment such that no services will be deployed.
split-stack-consistent-hostname-format.yaml environment will set the
<role-name>HostnameFormat parameters for each role defined in
the role files used. The server hostnames for the 2 stacks must be the same,
otherwise the servers will not be able to pull their deployment metadata from
Do not pass any network isolation templates or NIC config templates to the
overcloud-baremetal stack deployment command. These will only be passed
overcloud-services stack deployment command.
Services Deployment Command¶
The services stack,
overcloud-services will now be deployed with a separate
openstack overcloud deploy \ <other cli arguments> \ --stack overcloud-services \ --disable-validations \ -r roles-data.yaml \ -e /usr/share/openstack-tripleo-heat-templates/environments/deployed-server-environment.yaml \ -e /usr/share/openstack-tripleo-heat-templates/environments/deployed-server-deployed-neutron-ports.yaml \ -e /usr/share/openstack-tripleo-heat-templates/environments/deployed-server-bootstrap-environment-centos.yaml \ -e /usr/share/openstack-tripleo-heat-templates/environments/split-stack-consistent-hostname-format.yaml
overcloud-services stack makes use of the “deployed-server” feature.
The additional environments needed are shown in the above command. See
Using Already Deployed Servers for more information on how to fully configure the
The roles file,
roles-data.yaml is again passed to the services stack as
the same roles file should be used for both stacks.
split-stack-consistent-hostname-format.yaml environment is again
passed, so that the hostnames used for the server resources created by Heat are
the same as were created in the previous baremetal stack.
During this deployment, any network isolation environments and/or NIC config templates should be passed for the desired network configuration.
The stack should complete and the generated
overcloudrc can be used to
interact with the Overcloud.