Changing the CRI-O with Machine Config for Db2 Warehouse

You can use the Machine Config operator to manually update the OpenShift® system where Db2® Warehouse is running by using the OpenShift Container Platform (OCP) console or CLI.

About this task

CRI-O allows Kubernetes to use any Open Container Initiative (OCI)-compliant runtime to run pods. These pods share a namespace and live in the same control group (cgroup).

The Machine Config operator focuses on the operating system itself, managing updates to systemd, CRI-O/kubelet, kernel, NetworkManager, and the like. It also offers a MachineConfig CRD that can write configuration files onto the host.

Note that the steps for changing the CRI-O depend on the OpenShiftversion that you are using.

Procedure

For deployments on OpenShift versions 4.8 and 4.10, follow these steps:

Set the CRI-O max process IDs (PIDs) limit to 16384 by creating a ContainerRuntimeConfig resource.

The following example of a ContainerRuntimeConfig resource sets the PIDs limit to 16k on all worker nodes:

apiVersion: machineconfiguration.openshift.io/v1
kind: ContainerRuntimeConfig
metadata:
 name: crio-pids-limit
spec:
 machineConfigPoolSelector:
   matchLabels:
     pools.operator.machineconfiguration.openshift.io/worker: '' 
 containerRuntimeConfig:
   pidsLimit: 16384

Important:
To change this setting on OpenShift Service on AWS (ROSA) or Azure (ARO), you must have a Support Exception from Red Hat. For more information, see Change pids_limit in OSD/ROSA/ARO on the Red Hat Customer Portal.

For deployments on Red Hat OpenShift version 4.12, the PIDS limit is set in a KubeletConfig.
1. Log in to OpenShift Container Platform as an admin user:
```
oc login ${OCP_URL}
```
2. Label the MachineConfigPool custom resource on the worker nodes:
```
oc label machineconfigpool worker custom-crio=pid-limit --overwrite
```
3. Create the KubeletConfig that defines the podPidsLimit:
```
oc apply -f - << EOF
apiVersion: machineconfiguration.openshift.io/v1
kind: KubeletConfig
metadata:
  name: cpd-pidslimit-kubeletconfig
spec:
  kubeletConfig:
    podPidsLimit: 16384
  machineConfigPoolSelector:
    matchLabels:
      custom-crio: pid-limit
EOF
```