ping command fails in Db2 cluster

1. Find the respective db2ucluster resource name and create a db2ucluster environment variable:

   oc get db2ucluster --all-namespaces

   db2ucluster=db2ucluster_resource_name

2. Configure namespace and statefulset variables:

   namespace=$(oc get db2ucluster --all-namespaces | grep ${db2ucluster} | awk {'print $1'})

   statefulset=$(oc get sts -n ${namespace} | grep ${db2ucluster}-db2u | awk {'print $1'})

3. To determine if the db2ucluster deployment is restricted: true, run the following command:

   oc get db2ucluster ${db2ucluster} -o yaml | grep -i restricted

   ---

   The command returns restricted: true

   Run the following patch command:

   oc exec -it ${statefulset}-0 -- /bin/bash -c "touch /db2u/tmp/.pause_probe"

   ---

   The command returns restricted: false or nothing

   Proceed to the next step.

   ---

4. Wait for the formation status of the Db2 StatefulSet to become OK before proceeding to the next step. To obtain the status, run the following command:

   oc get formations.db2u.databases.ibm.com ${db2ucluster} -n ${namespace} -o go-template='{{range .status.components}}{{printf "%s,%s,%s\n" .kind .name .status.state}}{{end}}' | column -s, -t

   Look for the following result:

   StatefulSet ${db2ucluster}-db2u OK

5. There are two different commands to patch the StatefulSet. To determine which command to use, run the following command:

   oc get sts ${statefulset} -o yaml | grep sysctl

   ---

   The command does not return an output

   Run the following patch command:

   oc patch sts ${statefulset} -n ${namespace} -p '{"spec": {"template":{"spec":{"securityContext":{"sysctls":[{"name": "net.ipv4.ping_group_range","value": "0 2147483647"}]}}}}}'

   ---

   The command returns an output such as sysctls: and nothing else

   Run the following patch command:

   oc patch sts ${statefulset} -n ${namespace} --type json -p '[{"op":"add","path":"/spec/template/spec/securityContext/sysctls/-","value":{"name":"net.ipv4.ping_group_range","value":"0 2147483647"}}]'

   ---

   The db2u-0 pod will enter a terminating state and restart. Wait for the db2u-0 pod to become 1/1 Running state before proceeding to the next step.

6. To ensure that the db2u-0 pod completed the entry point, the end of the pod log includes a timestamp similar to the following:

   
   =========================================
   ### STARTTIME=20220817154656 ###"
   ### ENDTIME=20220817155051     ###"
   ### TIMEDIFF=395 s ###"
   =========================================
   + exit 0

oc get sts ${statefulset} -n ${namespace} -o yaml | grep "net.ipv4.ping_group_range"

- name: net.ipv4.ping_group_range

sysctls:
- name: net.ipv4.ping_group_range
  value: 0 2147483647