Using container commands - Db2uInstance

You can restore a snapshot backup of your Db2 database by putting your database in maintenance mode and restoring your volume snapshots.

About this task

Important: In running these steps, you might be at risk of losing your data unless you take the mentioned precautions.
Note: The LDAP service provided by Db2/Db2 Warehouse is only used if enabled. If you are not using the LDAP service provided by Db2/Db2 Warehouse, you do not need to run any commands involving LDAP_DEPLOY.

Procedure

  1. Put your Db2uInstance in maintenance mode: 
    DB2U_INSTANCE=$(oc get db2uinstance --no-headers | head -n1 | awk '{print $1}'); echo $DB2U_INSTANCE
    oc annotate db2uinstance $DB2U_INSTANCE db2u.databases.ibm.com/maintenance-pause-reconcile=true --overwrite
  2. Scale down your deployment: 
    NUM_REPLICAS=$(oc get db2uengine ${DB2U_ENGINE} -ojsonpath={.spec.replicas})
    DB2U_ENGINE=$(oc get db2uengine --selector="app=${DB2U_INSTANCE},type=engine" --no-headers | awk '{print $1}'); echo $DB2U_ENGINE
    ETCD_STS=$(oc get sts --selector="app=${DB2U_INSTANCE},component=etcd" --no-headers | awk '{print $1}'); echo $ETCD_STS
    oc patch db2uengine ${DB2U_ENGINE} --type merge --patch '{"spec": {
"replicas": 0} }'
    oc scale sts ${ETCD_STS} --replicas=0
    LDAP_DEPLOY=$(oc get sts --selector="app=${DB2U_INSTANCE},role=ldap" --no-headers | awk '{print $1}'); echo $LDAP_DEPLOY
    oc scale deploy ${LDAP_DEPLOY} --replicas=0
  3. Copy the existing persistent volume claim (PVC) definitions: 
    oc label pvc c-${DB2U_INSTANCE}-meta app=${DB2U_INSTANCE}
    oc label pvc c-${DB2U_INSTANCE}-backup app=${DB2U_INSTANCE}
    oc label pvc c-${DB2U_INSTANCE}-share app=${DB2U_INSTANCE}
    for PVC in $(oc get pvc -l app=$DB2U_INSTANCE --no-headers | awk '{print $1}'); do oc get pvc $PVC -oyaml > ${PVC}_copy.yaml ; done
  4. Set your existing PVs reclaim policy to retain in case something goes wrong: 
    for PV in $(oc get pv --no-headers | grep $DB2U_INSTANCE | awk '{print $1}'); do oc patch pv $PV -p "{\"spec\":{\"persistentVolumeReclaimPolicy\":\"Retain\"}}" ; done
    Important: Manually verify that each PV is set to retain or you are at risk of losing your data.
  5. Delete the existing PVCs: 
    oc delete pvc -l app=${DB2U_INSTANCE}
    CAUTION:
    Do this step only if you are confident that you are able to restore your volume snapshots, and your PV reclaim policies are set to retain. If you are unsure, try the next step instead by restoring your volume snapshots to dummy PVCs with different names first.
  6. Restore your volume snapshot to PVCs with the same name and namespace that you copied in step 3.
    The steps will differ depending on your provider:
  7. Scale up your deployment: 
    oc scale sts ${ETCD_STS} --replicas=1
    oc patch db2uengine ${DB2U_ENGINE} --type merge --patch '{"spec": { "replicas": '${NUM_REPLICAS}' } }'
    oc scale deploy ${LDAP_DEPLOY} --replicas=1
  8. Bring the database out of write-suspend after restoring: 
    CATALOG_POD=$(oc get po -l name=dashmpp-head-0,app=${DB2U_INSTANCE} --no-headers | awk '{print $1}')
    oc exec -it ${CATALOG_POD} -- manage_snapshots --action restore
  9. Exit maintenance mode: 
    oc annotate db2uinstance $DB2U_INSTANCE db2u.databases.ibm.com/maintenance-pause-reconcile- --overwrite