TripleO can be used with servers that have already been deployed and provisioned with a running operating system.

In this deployment scenario, Nova and Ironic from the Undercloud are not used to do any server deployment, installation, or power management. An external to TripleO and already existing provisioning tool is expected to have already installed an operating system on the servers that are intended to be used as nodes in the Overcloud.

Note

It’s an all or nothing approach when using already deployed servers. Mixing using deployed servers with servers provisioned with Nova and Ironic is not currently possible.

Benefits to using this feature include not requiring a dedicated provisioning network, and being able to use a custom partitioning scheme on the already deployed servers.

## Deployed Server Requirements¶

### Networking¶

#### Network interfaces¶

It’s recommended that each server have a dedicated management NIC with externally configured connectivity so that the servers are reachable outside of any networking configuration done by the OpenStack deployment.

A separate interface, or set of interfaces should then be used for the OpenStack deployment itself, configured in the typical fashion with a set of NIC config templates during the Overcloud deployment. See Configuring Network Isolation for more information on configuring networking.

Note

When configuring network isolation be sure that the configuration does not result in a loss of network connectivity from the deployed servers to the undercloud. The interface(s) that are being used for this connectivity should be excluded from the NIC config templates so that the configuration does not unintentionally drop all networking access to the deployed servers.

#### Undercloud¶

Neutron in the Undercloud is not used for providing DHCP services for the Overcloud nodes, hence a dedicated provisioning network with L2 connectivity is not a requirement in this scenario. Neutron is however still used for IPAM for the purposes of assigning IP addresses to the port resources created by tripleo-heat-templates.

Network L3 connectivity is still a requirement between the Undercloud and Overcloud nodes. The Overcloud nodes will communicate over HTTP(s) to poll the Undercloud for software configuration to be applied by their local agents.

The polling process requires L3 routable network connectivity from the deployed servers to the Undercloud OpenStack API’s.

If the ctlplane is a routable network from the deployed servers, then the deployed servers can connect directly to the IP address specified by local_ip from undercloud.conf. Alternatively, they could connect to the virtual IP address (VIP) specified by undercloud_public_host, if VIP’s are in use.

In the scenario where the ctlplane is not routable from the deployed servers, then undercloud_public_host in undercloud.conf must be set to a hostname that resolves to a routable IP address for the deployed servers. SSL also must be configured on the Undercloud so that HAProxy is bound to that configured hostname. Specify either undercloud_service_certifcate or generate_service_certificate to enable SSL during the Undercloud installation. See Deploying with SSL for more information on configuring SSL.

Additionally, when the ctlplane is not routable from the deployed servers, Heat on the Undercloud must be configured to use the public endpoints for OpenStack service communication during the polling process and be configured to use Swift temp URL’s for signaling. Add the following hiera data to a new or existing hiera file:

heat_clients_endpoint_type: public
heat::engine::default_deployment_signal_transport: TEMP_URL_SIGNAL


Specify the path to the hiera file with the hieradata_override configuration in undercloud.conf:

hieradata_override = /path/to/custom/hiera/file.yaml


#### Overcloud¶

Configure the deployed servers that will be used as nodes in the Overcloud with L3 connectivity to the Undercloud as needed. The configuration could be done via static or DHCP IP assignment.

Further networking configuration of Overcloud nodes is the same as in a typical TripleO deployment, except for:

• Initial configuration of L3 connectivity to the Undercloud
• No requirement for dedicating a separate L2 network for provisioning

#### Testing Connectivity¶

On each Overcloud node run the following commands that test connectivity to the Undercloud’s IP address where OpenStack services are bound. Use either local_ip or undercloud_public_host in the following examples.

Test basic connectivity to the Undercloud:

ping <undercloud local_ip>


Test HTTP/HTTPS connectivity to Heat API on the Undercloud:

curl <undercloud local_ip>:8000


Sample output:

{"versions": [{"status": "CURRENT", "id": "v1.0", "links": [{"href": "http://10.12.53.41:8000/v1/", "rel": "self"}]}]}


Test HTTP/HTTPS connectivity to Swift on the Undercloud The html output shown here is expected! While it indicates no resource was found, it demonstrates successful connectivity to the HTTP service:

curl <undercloud local_ip>:8080


Sample output:

<html><h1>Not Found</h1><p>The resource could not be found.</p></html>


The output from the above curl commands demonstrates successful connectivity to the web services bound at the Undercloud’s local_ip IP address. It’s important to verify this connectivity prior to starting the deployment, otherwise the deployment may be unsuccessful and difficult to debug.

### Package repositories¶

The servers will need to already have the appropriately enabled yum repositories as packages will be installed on the servers during the Overcloud deployment. The enabling of repositories on the Overcloud nodes is the same as it is for other areas of TripleO, such as Undercloud installation. See Repository Enablement for the detailed steps on how to enable the standard repositories for TripleO.

### Initial Package Installation¶

Once the repositories have been enabled on the deployed servers, the initial packages for the Heat agent need to be installed. Run the following command on each server intending to be used as part of the Overcloud:

sudo yum install python-heat-agent*


### Certificate Authority Configuration¶

If SSL is enabled on the Undercloud endpoints, the deployed servers need to be configured to trust the Certificate Authority (CA) that signed the SSL certificates.

On a default Undercloud install with SSL where the CA is automatically generated, the CA file will be at /etc/pki/ca-trust/source/anchors/cm-local-ca.pem. Copy this CA file to the /etc/pki/ca-trust/source/anchors/ directory on each deployed server. Then run the following command on each server to update the CA trust:

sudo update-ca-trust extract


## Deploying the Overcloud¶

### Deployment Command¶

The functionality of using already deployed servers is enabled by passing additional Heat environment files to the openstack overcloud deploy command.:

openstack overcloud deploy \
<other cli arguments> \
--disable-validations \
-e /usr/share/openstack-tripleo-heat-templates/environments/deployed-server-environment.yaml \
-e /usr/share/openstack-tripleo-heat-templates/environments/deployed-server-bootstrap-environment-centos.yaml \
-r /usr/share/openstack-tripleo-heat-templates/deployed-server/deployed-server-roles-data.yaml


The --disable-validations option disables the basic Nova, Ironic, and Glance related validations executed by python-tripleoclient. These validations are not necessary since those services will not be used to deploy the Overcloud.

The deployed-server.yaml environment takes advantage of the template composition nature of Heat and tripleo-heat-templates to substitute OS::Heat::DeployedServer resources in place of OS::Nova::Server.

The deployed-server-bootstrap-centos.yaml environment triggers execution of a bootstrap script on the deployed servers to install further needed packages and make other configurations necessary for Overcloud deployment.

The custom roles file, deployed-server-roles-data.yaml contains the custom roles used during the deployment. Further customization of the roles data is possible when using deployed servers. When doing so, be sure to include the disable_constraints key on each defined role as seen in deployed-server-roles-data.yaml. This key disables the Heat defined constraints in the generated role templates. These constraints validate resources such as Nova flavors and Glance images, resources that are not needed when using deployed servers. An example role using disable_constraints looks like:

- name: ControllerDeployedServer
disable_constraints: True
CountDefault: 1
ServicesDefault:
- OS::TripleO::Services::CACerts
- OS::TripleO::Services::CephMon
- OS::TripleO::Services::CephExternal
- OS::TripleO::Services::CephRgw


Optionally include an environment to set the DeploymentSwiftDataMap paramter called deployment-swift-data-map.yaml:

# Append to deploy command
-e deployment-swift-data-map.yaml \


This environment sets the Swift container and object names for the deployment metadata for each deployed server. This environment file must be written entirely by the user. Example contents are as follows:

parameter_defaults:
DeploymentSwiftDataMap:
overcloud-controller-0:
container: overcloud-controller
object: 0
overcloud-controller-1:
container: overcloud-controller
object: 1
overcloud-controller-2:
container: overcloud-controller
object: 2
overcloud-novacompute-0:
container: overcloud-compute
object: 0


The DeploymentSwiftDataMap parameter’s value is a dict. The keys are the Heat assigned names for each server resource. The values are another dict of the Swift container and object name Heat should use for storing the deployment data for that server resource. These values should match the container and object names as described in the Pre-configuring metadata agent configuration section.

When using config-download with deployed-server (pre-provisioned nodes), a HostnameMap parameter must be provided. Create an environment file to define the parameter, and assign the node hostnames in the parameter value. The following example shows a sample value:

parameter_defaults:
HostnameMap:
overcloud-controller-0: controller-00-rack01
overcloud-controller-1: controller-01-rack02
overcloud-controller-2: controller-02-rack03
overcloud-novacompute-0: compute-00-rack01
overcloud-novacompute-1: compute-01-rack01
overcloud-novacompute-2: compute-02-rack01


Write the contents to an environment file such as hostnamemap.yaml, and pass it the environment as part of the deployment command.

#### Network Configuration¶

The default network interface configuration mappings for the deployed-server roles are:

OS::TripleO::ControllerDeployedServer::Net::SoftwareConfig: net-config-static-bridge.yaml
OS::TripleO::ComputeDeployedServer::Net::SoftwareConfig: net-config-static.yaml
OS::TripleO::BlockStorageDeployedServer::Net::SoftwareConfig: net-config-static.yaml
OS::TripleO::ObjectStorageDeployedServer::Net::SoftwareConfig: net-config-static.yaml
OS::TripleO::CephStorageDeployedServer::Net::SoftwareConfig: net-config-static.yaml


The default NIC configs use static IP assignment instead of the default of DHCP. This is due to there being no requirement of L2 connectivity between the undercloud and overcloud. However, the NIC config templates can be overridden to use whatever configuration is desired (including DHCP).

As is the case when not using deployed-servers, the following parameters need to also be specified:

parameter_defaults:
NeutronPublicInterface: eth1
ControlPlaneDefaultRoute: 192.168.24.1


ControlPlaneDefaultRoute and EC2MetadataIp are not necessarily meaningful parameters depending on the network architecture in use with deployed servers. However, they still must be specified as they are required parameters for the template interface.

The DeployedServerPortMap parameter can be used to assign fixed IP’s from either the ctlplane network or the IP address range for the overcloud.

If the deployed servers were preconfigured with IP addresses from the ctlplane network for the initial undercloud connectivity, then the same IP addresses can be reused during the overcloud deployment. Add the following to a new environment file and specify the environment file as part of the deployment command:

resource_registry:
OS::TripleO::DeployedServer::ControlPlanePort: ../deployed-server/deployed-neutron-port.yaml
parameter_defaults:
DeployedServerPortMap:
controller0-ctlplane:
fixed_ips:
subnets:
- cidr: 192.168.24.0/24
compute0-ctlplane:
fixed_ips:
subnets:
- cidr: 192.168.24..0/24


The value of the DeployedServerPortMap variable is a map. The keys correspond to the <short hostname>-ctlplane of the deployed servers. Specify the ip addresses and subnet CIDR to be assigned under fixed_ips.

In the case where the ctlplane is not routable from the deployed servers, you can use DeployedServerPortMap to assign an IP address from any CIDR:

resource_registry:
OS::TripleO::DeployedServer::ControlPlanePort: /usr/share/openstack-tripleo-heat-templates/deployed-server/deployed-neutron-port.yaml
OS::TripleO::Network::Ports::ControlPlaneVipPort: /usr/share/openstack-tripleo-heat-templates/deployed-server/deployed-neutron-port.yaml
OS::TripleO::Network::Ports::RedisVipPort: /usr/share/openstack-tripleo-heat-templates/network/ports/noop.yaml

parameter_defaults:
NeutronPublicInterface: eth1
ControlPlaneDefaultRoute: 192.168.100.1

DeployedServerPortMap:
control_virtual_ip:
fixed_ips:
subnets:
- cidr: 192.168.100.0/24
controller0-ctlplane:
fixed_ips:
subnets:
- cidr: 192.168.100.0/24
compute0-ctlplane:
fixed_ips:
subnets:
- cidr: 192.168.100.0/24


In the above example, notice how RedisVipPort is mapped to network/ports/noop.yaml. This mapping is due to the fact that the Redis VIP IP address comes from the ctlplane by default. The EC2MetadataIp and ControlPlaneDefaultRoute parameters are set to the value of the control virtual IP address. These parameters are required to be set by the sample NIC configs, and must be set to a pingable IP address in order to pass the validations performed during deployment. Alternatively, the NIC configs could be further customized to not require these parameters.

When using network isolation, refer to the documentation on using fixed IP addresses for further information at Predictable IPs.

### Configuring Deployed Servers to poll Heat¶

Beginning with the Pike release of TripleO, the deployed server’s agents can be configured for polling of the Heat deployment data independently of creating the overcloud stack.

This is accomplished using the DeploymentSwiftDataMap parameter as shown in the previous section. Once the Swift container and object names are chosen for each deployed server, create Swift temporary url’s that correspond to each container/object and configure the temporary url in the agent configuration for the respective deployed server.

For this example, the following DeploymentSwiftDataMap parameter value is assumed to be:

parameter_defaults:
DeploymentSwiftDataMap:
overcloud-controller-0:
container: overcloud-controller
object: 0
overcloud-controller-1:
container: overcloud-controller
object: 1
overcloud-controller-2:
container: overcloud-controller
object: 2
overcloud-novacompute-0:
container: overcloud-compute
object: 0


Start by showing the Swift account and temporary URL key:

swift stat


Sample output looks like:

Account: AUTH_aa7784aae1ae41c38e6e01fd76caaa7c
Containers: 5
Objects: 706
Bytes: 3521748
Containers in policy "policy-0": 5
Objects in policy "policy-0": 706
Bytes in policy "policy-0": 3521748
X-Account-Project-Domain-Id: default
X-Timestamp: 1499288311.20888
Content-Type: text/plain; charset=utf-8
Accept-Ranges: bytes


Record the value of Account and Meta Temp-Url-Key from the output from the above command.

If Meta Temp-Url-Key is not set, it can be set by running the following command (choose a unique value for the actual key value):

swift post -m "Temp-URL-Key:b3968d0207b54ece87cccc06515a89d4"


Create temporary URL’s for each Swift object specified in DeploymentSwiftDataMap:

swift tempurl GET 600000000 /v1/AUTH_aa7784aae1ae41c38e6e01fd76caaa7c/overcloud-controller/0 25ad317c25bb89c62f5730f3b8cf8fca
swift tempurl GET 600000000 /v1/AUTH_aa7784aae1ae41c38e6e01fd76caaa7c/overcloud-controller/1 25ad317c25bb89c62f5730f3b8cf8fca
swift tempurl GET 600000000 /v1/AUTH_aa7784aae1ae41c38e6e01fd76caaa7c/overcloud-controller/2 25ad317c25bb89c62f5730f3b8cf8fca
swift tempurl GET 600000000 /v1/AUTH_aa7784aae1ae41c38e6e01fd76caaa7c/overcloud-compute/0 25ad317c25bb89c62f5730f3b8cf8fca


See swift tempurl --help for a detailed explanation of each argument.

The above commands output URL paths which need to be joined with the Swift public api endpoint to construct the full metadata URL. In a default TripleO deployment, this value is http://192.168.24.1:8080 but is likely different for any real deployment.

Joining the output from one of the above commands with the Swift public endpoint results in a URL that looks like:

http://192.168.24.1:8080/v1/AUTH_aa7784aae1ae41c38e6e01fd76caaa7c/overcloud-controller/0?temp_url_sig=92de8e4c66b77c54630dede8150b3ebcd46a1fca&temp_url_expires=700000000


Once each URL is obtained, configure the agent on each deployed server with its respective metadata URL (e.g., use the metadata URL for controller 0 on the deployed server intended to be controller 0, etc). Create the following file (and local-data directory if necessary). Both should be root owned:

mkdir -p /var/lib/os-collect-config/local-data
/var/lib/os-collect-config/local-data/deployed-server.json


Example file contents:

{
"os-collect-config": {
"collectors": ["request", "local"],
"request": {
}
}
}


The deployed server’s agent is now configured.

If not using DeploymentSwiftDataMap, the metadata configuration will have to be read directly from Heat once the stack starts to create.

Upon executing the deployment command, Heat will begin creating the overcloud stack. The stack events are shown in the terminal as the stack operation is in progress.

The resources corresponding to the deployed server will enter CREATE_IN_PROGRESS. At this point, the Heat stack will not continue as it is waiting for signals from the servers. The agents on the deployed servers need to be configured to poll Heat for their configuration.

This point in the Heat events output will look similar to:

2017-01-14 13:25:13Z [overcloud.Compute.0.NovaCompute]: CREATE_IN_PROGRESS  state changed
2017-01-14 13:25:14Z [overcloud.Controller.0.Controller]: CREATE_IN_PROGRESS  state changed
2017-01-14 13:25:14Z [overcloud.Controller.1.Controller]: CREATE_IN_PROGRESS  state changed
2017-01-14 13:25:15Z [overcloud.Controller.2.Controller]: CREATE_IN_PROGRESS  state changed


The example output above is from a deployment with 3 controllers and 1 compute. As seen, these resources have entered the CREATE_IN_PROGRESS state.

To configure the agents on the deployed servers, the request metadata url needs to be read from Heat resource metadata on the individual resources, and configured in the /etc/os-collect-config.conf configuration file on the corresponding deployed servers.

##### Manual configuration of Heat agents¶

These steps can be used to manually configure the Heat agents (os-collect-config) on the deployed servers.

Query Heat for the request metadata url by first listing the nested deployed-server resources:

openstack stack resource list -n 5 overcloud | grep deployed-server


Example output:

| deployed-server | 895c08b8-f6f4-4564-b344-586603e7e970 | OS::Heat::DeployedServer | CREATE_COMPLETE    | 2017-01-14T13:25:12Z | overcloud-Controller-pgeu4nxsuq6r-1-v4slfaduprak-Controller-ltxdxz2fin3d |
| deployed-server | 87cd8d81-8bbe-4c0b-9bd9-f5bcd1343265 | OS::Heat::DeployedServer | CREATE_COMPLETE    | 2017-01-14T13:25:15Z | overcloud-Controller-pgeu4nxsuq6r-0-5uin56wp3ign-Controller-5wkislg4kiv5 |
| deployed-server | 3d387f61-dc6d-41f7-b3b8-5c9a0ab0ed7b | OS::Heat::DeployedServer | CREATE_COMPLETE    | 2017-01-14T13:25:16Z | overcloud-Controller-pgeu4nxsuq6r-2-m6tgzatgnqrb-Controller-yczqaulovrla |
| deployed-server | cc230478-287e-4591-a905-bbfca6c89742 | OS::Heat::DeployedServer | CREATE_COMPLETE    | 2017-01-14T13:25:13Z | overcloud-Compute-vllmnqf5d77h-0-kfm2xsdmtmr6-NovaCompute-67djxtyrwi6z |


Show the resource metadata for one of the resources. The last column in the above output is a nested stack name and is used in the command below. The command shows the resource metadata for the first controller (Controller.0):

openstack stack resource metadata overcloud-Controller-pgeu4nxsuq6r-0-5uin56wp3ign-Controller-5wkislg4kiv5 deployed-server


The above command outputs a significant amount of JSON output representing the resource metadata. To see just the request metadata_url, the command can be piped to jq to show just the needed url:

openstack stack resource metadata overcloud-Controller-pgeu4nxsuq6r-0-5uin56wp3ign-Controller-5wkislg4kiv5 deployed-server | jq -r '.["os-collect-config"].request.metadata_url'


Example output:

http://10.12.53.41:8080/v1/AUTH_cf85adf63bc04912854473ff2b08b5a2/ov-ntroller-5wkislg4kiv5-deployed-server-yc4lx2d43dmb/244744c2-4af1-4626-92c6-94b2f78e3791?temp_url_sig=6d33b16ee2ae166a306633f04376ee54f0451ae4&temp_url_expires=2147483586


Using the above url, configure /etc/os-collect-config.conf on the deployed server that is intended to be used as Controller 0. The full configuration would be:

[DEFAULT]
collectors=request
command=os-refresh-config
polling_interval=30

[request]


Once the configuration has been updated on the deployed server for Controller 0, restart the os-collect-config service:

sudo systemctl restart os-collect-config


Repeat the configuration for the other nodes in the Overcloud, by querying Heat for the request metadata url, and updating the os-collect-config configuration on the respective deployed servers.

Once all the agents have been properly configured, they will begin polling for the software deployments to apply locally from Heat, and the Heat stack will continue creating. If the deployment is successful, the Heat stack will eventually go to the CREATE_COMPLETE state.

##### Automatic configuration of Heat agents¶

A script is included with tripleo-heat-templates that can be used to do automatic configuration of the Heat agent on the deployed servers instead of relying on the above manual process.

The script requires that the environment variables needed to authenticate with the Undercloud’s keystone have been set in the current shell. These environment variables can be set by sourcing the Undercloud’s stackrc file.

The script also requires that the user executing the script can ssh as the same user to each deployed server, and that the remote user account has password-less sudo access.

The following shows an example of running the script:

export OVERCLOUD_ROLES="ControllerDeployedServer ComputeDeployedServer"
export ControllerDeployedServer_hosts="192.168.25.1 192.168.25.2 192.168.25.3"
export ComputeDeployedServer_hosts="192.168.25.4"
tripleo-heat-templates/deployed-server/scripts/get-occ-config.sh


As shown above, the script is further configured by the $OVERCLOUD_ROLES environment variable, and corresponding $<role-name>_hosts variables.

$OVERCLOUD_ROLES is a space separated list of the role names used for the Overcloud deployment. These role names correspond to the name of the roles from the roles data file used during the deployment. Each $<role-name>_hosts variable is a space separated list of IP addresses that are the IP addresses of the deployed servers for the roles. For example, in the above command, 192.168.25.1 is the IP of Controller 0, 192.168.25.2 is the IP of Controller 1, etc.

The script will take care of querying Heat for each request metadata url, configure the url in the agent configuration file on each deployed server, and restart the agent service.

Once the script executes successfully, the deployed servers will start polling Heat for software deployments and the stack will continue creating.

## Scaling the Overcloud¶

### Scaling Up¶

When scaling up the Overcloud, the heat agents on the new servers being added to the deployment need to be configured to correspond to the new nodes being added.

For example, when scaling out compute nodes, the steps to be completed by the user are as follows:

1. Prepare the new deployed server(s) as shown in Deployed Server Requirements.
2. Start the scale out command. See Scaling overcloud roles for reference.
3. Once Heat has created the new resources for the new deployed server(s), query Heat for the request metadata url for the new nodes, and configure the remote agents as shown in Manual configuration of Heat agents. The manual configuration of the agents should be used when scaling up because the automated script method will reconfigure all nodes, not just the new nodes being added to the deployment.

### Scaling Down¶

When scaling down the Overcloud, follow the scale down instructions as normal as shown in Deleting Overcloud Nodes, however use the following command to get the uuid values to pass to openstack overcloud node delete instead of using nova list:

openstack stack resource list overcloud -n5 --filter type=OS::TripleO::<RoleName>Server


Replace <RoleName> in the above command with the actual name of the role that you are scaling down. The stack_name column in the command output can be used to identify the uuid associated with each node. The stack_name will include the integer value of the index of the node in the Heat resource group. For example, in the following sample output:

\$ openstack stack resource list overcloud -n5 --filter type=OS::TripleO::ComputeDeployedServerServer
+-----------------------+--------------------------------------+------------------------------------------+-----------------+----------------------+-------------------------------------------------------------+
| resource_name         | physical_resource_id                 | resource_type                            | resource_status | updated_time         | stack_name                                                  |
+-----------------------+--------------------------------------+------------------------------------------+-----------------+----------------------+-------------------------------------------------------------+
| ComputeDeployedServer | 66b1487c-51ee-4fd0-8d8d-26e9383207f5 | OS::TripleO::ComputeDeployedServerServer | CREATE_COMPLETE | 2017-10-31T23:45:18Z | overcloud-ComputeDeployedServer-myztzg7pn54d-0-pixawichjjl3 |
| ComputeDeployedServer | 01cf59d7-c543-4f50-95df-6562fd2ed7fb | OS::TripleO::ComputeDeployedServerServer | CREATE_COMPLETE | 2017-10-31T23:45:18Z | overcloud-ComputeDeployedServer-myztzg7pn54d-1-ooCahg1vaequ |
| ComputeDeployedServer | 278af32c-c3a4-427e-96d2-3cda7e706c50 | OS::TripleO::ComputeDeployedServerServer | CREATE_COMPLETE | 2017-10-31T23:45:18Z | overcloud-ComputeDeployedServer-myztzg7pn54d-2-xooM5jai2ees |
+-----------------------+--------------------------------------+------------------------------------------+-----------------+----------------------+-------------------------------------------------------------+


The index 0, 1, or 2 can be seen in the stack_name column. These indices correspond to the order of the nodes in the Heat resource group. Pass the corresponding uuid value from the physical_resource_id column to openstack overcloud node delete command.

The physical deployed servers that have been removed from the deployment need to be powered off. In a deployment not using deployed servers, this would typically be done with Ironic. When using deployed servers, it must be done manually, or by whatever existing power management solution is already in place. If the nodes are not powered down, they will continue to be operational and could be part of the deployment, since there are no steps to unconfigure, uninstall software, or stop services on nodes when scaling down.

Once the nodes are powered down and all needed data has been saved from the nodes, it is recommended that they be reprovisioned back to a base operating system configuration so that they do not unintentionally join the deployment in the future if they are powered back on.

Note

Do not attempt to reuse nodes that were previously removed from the deployment without first reprovisioning them using whatever provisioning tool is in place.

## Deleting the Overcloud¶

When deleting the Overcloud, the Overcloud nodes need to be manually powered off, otherwise, the cloud will still be active and accepting any user requests.

After archiving important data (log files, saved configurations, database files), that needs to be saved from the deployment, it is recommended to reprovision the nodes to a clean base operating system. The reprovision will ensure that they do not start serving user requests, or interfere with future deployments in the case where they are powered back on in the future.

Note

As with scaling down, do not attempt to reuse nodes that were previously part of a now deleted deployment in a new deployment without first reprovisioning them using whatever provisioning tool is in place.