ESS awareness with the installation toolkit

You can use the installation toolkit to install IBM Spectrum Scale™ and deploy protocols in a cluster containing Elastic Storage Server (ESS).

When using the installation toolkit in a cluster containing ESS, use the following high-level steps:

Add protocol nodes in the ESS cluster by issuing the following command.
```
./spectrumscale node add NodeName -p
```
You can add other types of nodes such as client nodes, NSD servers, and so on depending on your requirements. For more information, see Defining the cluster topology for the installation toolkit.
Specify one of the newly added protocol nodes as the installer node and specify the setup type by issuing the following command.
```
./spectrumscale setup -s NodeIP -i SSHIdentity -st ess
```
The installer node is the node on which the installation toolkit is extracted and from where the installation toolkit command, spectrumscale, is initiated.
Specify the EMS node of the ESS system to the installation toolkit by issuing the following command.
```
./spectrumscale node add NodeName -e
```
This node is also automatically specified as the admin node. The admin node, which must be the EMS node in an ESS configuration, is the node that has access to all other nodes to perform configuration during the installation.
You can use the config populate option of the installation toolkit to populate the cluster definition file with the current configuration of the EMS node, and the protocol and the client nodes in the cluster. In a cluster containing ESS, you must specify the EMS node with the config populate command. For example:
```
./spectrumscale config populate --node EMSNode
```
For more information, see Populating cluster definition file with current cluster state using the installation toolkit.
Proceed with specifying other configuration options, installing, and deploying by using the installation toolkit. For more information, see Defining the cluster topology for the installation toolkit, Installing GPFS and creating a GPFS cluster, and Deploying protocols.

Several validations are done when you use the installation toolkit in an ESS cluster to ensure that functions that are configured on ESS EMS and I/O server nodes are not affected. Additionally, some considerations apply when you are using the installation toolkit in an ESS cluster. These validations and considerations are as follows.

Adding ESS EMS node and I/O server nodes as protocol nodes is not allowed.
Adding GUI nodes in the ESS cluster by using the installation toolkit is not allowed. It is assumed that the EMS node is running a GUI setup and the ability to add more GUI nodes by using the installation toolkit is disabled to not affect the existing configuration. During upgrade, the installation toolkit does not alter an existing configuration that contains one or more GUI setups. The upgrade of any of these components is done outside of the ESS EMS and I/O server nodes, and their configuration is not changed.
Adding I/O server nodes as NSD nodes by using the installation toolkit is not allowed.
Creating NSDs and file systems from disks within the ESS I/O server nodes by using the installation toolkit is not allowed.
Specifying a cluster name by using the installation toolkit is not allowed. The existing cluster name is detected and used by the toolkit.
CES shared root file system must be mounted on all protocol nodes.
The installation toolkit installs a Chef RPM on the ESS nodes but does no other configuration changes. The Chef RPM can be safely removed, if needed.
Only performance monitoring sensor packages are installed on all nodes in an ESS cluster other than the ESS EMS and I/O server nodes. They are configured to point to the existing collector on the EMS node. Apart from package installation, the installation toolkit adds protocol-specific sensors to the overall cluster performance monitoring configuration during the installation and deployment phases. During upgrade, the installation toolkit does not alter an existing configuration that might have one or more collectors or sensors. The upgrade of any of these components is done outside of the ESS EMS and I/O server nodes, and their configuration is not changed.