Setting up dedicated nodes for your Db2 Warehouse deployment

You can dedicate one or more worker nodes to your Db2® Warehouse database service. The nodes are then used exclusively by the database containers or pods.

About this task

Red Hat® OpenShift® uses the concepts of taint and toleration to dedicate a service such as Db2 Warehouse to particular nodes. Nodes are tainted and labeled:

A taint prevents pods from being deployed on a tainted node.
A label allows for a pod with a matching toleration to be treated as an exception.

Taint and toleration work together to provide node exclusivity to deploying Db2 Warehouse on particular nodes

Perform these steps for each worker node that you plan to dedicate to the database deployment. The steps use Red Hat OpenShift CLI commands. The node_name is the name of a worker node on which you plan to host Db2 Warehouse.

Procedure

Retrieve the name of the worker node that you want to dedicate to Db2 Warehouse:
```
oc get nodes
```
Taint the node with the NoSchedule effect and safely evict all of the pods from that node:
```
oc adm taint node node_name icp4data=dedicated_specifier:NoSchedule --overwrite
oc adm drain node_name
oc adm uncordon node_name
```
Where dedicated_specifier is an identifier that is used to deploy a database only on nodes that have the dedicated_specifier label. By default, the dedicated_specifier for Db2 Warehouse is database-db2wh. The --overwrite flag is only required if the node is already tainted or labeled and ensures that the taint or label is replaced.
Important: In the case of an error after running the oc adm drain command, the administrator must review the error message and execute the command with the specified options.

Label the node:

oc label node node_name icp4data=dedicated_specifier --overwrite

Optional: Verify that the node is labeled:
```
oc get node --show-labels
```

What to do next

When you create a database deployment, you will provide the dedicated_specifier label that you used in the Value for node label field.