Deploying the Node Tuning Operator with a shell script

With Db2 Warehouse s11.5.8.0-cn2 and later, you can use the Red Hat OpenShift Node Tuning Operator to set interprocess communication (IPC) kernel parameters to run Db2 Warehouse with limited privileges. You can deploy the Node Tuning Operator with a shell script.

1. Create a shell script using a text editor such as Vim, and copy and paste the contents from the following YAML example.
   In this example, the script is saved in the path /root/script/crtNodeTuneCR.sh:

   #!/bin/bash
   
   # Compute IPC kernel parameters as per IBM Documentation topic
   # https://www.ibm.com/support/knowledgecenter/SSEPGG_11.1.0/com.ibm.db2.luw.qb.server.doc/doc/c0057140.html
   # and generate the Node Tuning Operator CR yaml.
   
   tuned_cr_yaml="/tmp/Db2UnodeTuningCR.yaml"
   mem_limit_Gi=0
   node_label=""
   cr_name="db2u-ipc-tune"
   cr_profile_name="openshift-db2u-ipc"
   cr_namespace="openshift-cluster-node-tuning-operator"
   create_cr="false"
   delete_cr="false"
   
   usage() {
       cat <<-USAGE #| fmt
       Usage: $0 [OPTIONS] [arg]
   
       OPTIONS:
       =======
       * -m|--mem-limit mem_limit  : The memory.limit (Gi) to be applied to Db2U deployment.
       * [-l|--label node_label]   : The node label to use for dedicated Cp4D deployments.
       * [-f|--file yaml_output]   : The NodeTuningOperator CR YAML output file. Default /tmp/Db2UnodeTuningCR.yaml.
       * [-c|--create]             : Create the NodeTuningOperator CR ${cr_name} using the generated CR yaml file.
       * [-d|--delete]             : Delete the NodeTuningOperator CR ${cr_name}.
       * [-h|--help]               : Display the help text of the script.
   USAGE
   }
   
   [[ $# -lt 1 ]] && { usage && exit 1; }
   
   while [[ $# -gt 0 ]]; do
       case "$1" in
           -f|--file) shift; tuned_cr_yaml=$1
           ;;
           -m|--mem-limit) shift; mem_limit_Gi=$1
           ;;
           -l|--label) shift; node_label=$1
           ;;
           -c|--create) create_cr="true"
           ;;
           -d|--delete) delete_cr="true"
           ;;
           -h|--help) usage && exit 0
           ;;
           *) usage && exit 1
           ;;
   	esac
   	shift
   done
   
   ((ram_in_BYTES=mem_limit_Gi * 1073741824))
   ((ram_GB=ram_in_BYTES / (1024 * 1024 * 1024)))
   ((IPCMNI_LIMIT=32 * 1024))
   tr ' ' '\n' < /proc/cmdline | grep -q ipcmni_extend && ((IPCMNI_LIMIT=8 * 1024 * 1024))
   
   #
   ### =============== functions ================ ###
   #
   # Compute the required kernel IPC parameter values
   compute_kernel_ipc_params() {
       local PAGESZ=$(getconf PAGESIZE)
   
       # Global vars
       ((shmmni=256 * ram_GB))
       shmmax=${ram_in_BYTES}
       ((shmall=2 * (ram_in_BYTES / PAGESZ)))
       ((msgmni=1024 * ram_GB))
       msgmax=65536
       msgmnb=${msgmax}
       SEMMSL=250
       SEMMNS=256000
       SEMOPM=32
       SEMMNI=${shmmni}
   
       # RH bugzilla https://access.redhat.com/solutions/4968021. Limit SEMMNI, shmmni and msgmni to the max
       # supported by the Linux kernel -- 32k (default) or 8M if kernel boot parameter 'ipcmni_extend' is set.
       ((SEMMNI=SEMMNI < IPCMNI_LIMIT ? SEMMNI : IPCMNI_LIMIT))
       ((shmmni=shmmni < IPCMNI_LIMIT ? shmmni : IPCMNI_LIMIT))
       ((msgmni=msgmni < IPCMNI_LIMIT ? msgmni : IPCMNI_LIMIT))
   }
   
   # Generate NodeTuning Operator YAML file
   gen_tuned_cr_yaml() {
       # Generate YAML file for NodeTuning CR and save as ${tuned_cr_yaml}
       cat <<-EOF > ${tuned_cr_yaml}
   apiVersion: tuned.openshift.io/v1
   kind: Tuned
   metadata:
     name: ${cr_name}
     namespace: ${cr_namespace}
   spec:
     profile:
     - name: ${cr_profile_name}
       data: |
         [main]
         summary=Tune IPC Kernel parameters on OpenShift nodes running Db2U engine PODs
         include=openshift-node
   
         [sysctl]
         kernel.shmmni = ${shmmni}
         kernel.shmmax = ${shmmax}
         kernel.shmall = ${shmall}
         kernel.sem = ${SEMMSL} ${SEMMNS} ${SEMOPM} ${SEMMNI}
         kernel.msgmni = ${msgmni}
         kernel.msgmax = ${msgmax}
         kernel.msgmnb = ${msgmnb}
   
     recommend:
     - match:
       - label: node-role.kubernetes.io/worker
   EOF
   
       # Add the optional dedicated label into match array
       if [[ -n "${node_label}" ]]; then
           cat <<-EOF >> ${tuned_cr_yaml}
       - label: icp4data
         value: ${node_label}
   EOF
       fi
   
       # Add the priority and profile keys
       cat <<-EOF >> ${tuned_cr_yaml}
       priority: 10
       profile: ${cr_profile_name}
   EOF
   
       [[ "${create_cr}" == "true" ]] && return
       cat <<-MSG
   ===============================================================================
   * Successfully generated the Node Tuning Operator Custom Resource Definition as
     ${tuned_cr_yaml} YAML with Db2U specific IPC sysctl settings.
   
   * Please run 'oc create -f ${tuned_cr_yaml}' on the master node to
     create the Node Tuning Operator CR to apply those customized sysctl values.
   ===============================================================================
   MSG
   }
   
   create_tuned_cr() {
       echo "Creating the Node Tuning Operator Custom Resource for Db2U IPC kernel parameter tuning ..."
       oc create -f ${tuned_cr_yaml}
       sleep 2
   
       # List the NodeTuning CR and describe
       oc -n ${cr_namespace} get Tuned/${cr_name}
       echo ""
   
       echo "The CR of the Node Tuning Operator deployed"
       echo "--------------------------------------------"
       oc -n ${cr_namespace} describe Tuned/${cr_name}
       echo ""
   }
   
   delete_tuned_cr() {
       echo "Deleting the Node Tuning Operator Custom Resource used for Db2U IPC kernel parameter tuning ..."
       oc -n ${cr_namespace} get Tuned/${cr_name} --no-headers -ojsonpath='{.kind}' | grep -iq tuned || \
           { echo "No matching CR found ..." && exit 0; }
       oc -n ${cr_namespace} delete Tuned/${cr_name}
       echo ""
       sleep 2
   
       # Get the list of containerized tuned PODs (DaemonSet) deployed on the cluster
       local tuned_pods=( $(oc -n ${cr_namespace} get po --selector openshift-app=tuned --no-headers -ojsonpath='{.items[*].metadata.name}') )
       # Remove the tuned profile directory deployed on those PODs
       for p in "${tuned_pods[@]}"; do
           echo "Removing the installed tuned profile ${cr_profile_name} on POD: $p"
           oc -n ${cr_namespace} exec -it $p -- bash -c "rm -fr /etc/tuned/${cr_profile_name}"
       done
       echo ""
   }
   
   #
   ### ================== Main ==================== ###
   #
   
   [[ "${delete_cr}" == "true" ]] && { delete_tuned_cr && exit 0; }
   
   compute_kernel_ipc_params
   
   gen_tuned_cr_yaml
   
   [[ "${create_cr}" == "true" ]] && create_tuned_cr

2. Make the script executable:

   chmod +x  /root/script/crtNodeTuneCR.sh

3. Run the script to create the TuneD custom resource:

   ./root/script/crtNodeTuneCR.sh