Migrate EBS Volume based PVs across AWS availability zones

migrate-pv-to-zone.sh

#!/bin/bash

set -eu

NAMESPACE=$1
PVCNAME=$2
TARGETZONE=$3
DEPLOYMENTOBJ=$4
PVNAME=$(oc -n $NAMESPACE get pvc $PVCNAME --template={{.spec.volumeName}})
VOLUMEID=$(oc -n $NAMESPACE get pv $PVNAME --template={{.spec.awsElasticBlockStore.volumeID}} | cut -d/ -f 4)
REPLICAS=$(oc -n $NAMESPACE get $DEPLOYMENTOBJ --template={{.spec.replicas}})

cat <<EOF
Summary

 Namespace ---------- $NAMESPACE
 Deployment object -- $DEPLOYMENTOBJ
 PVC Name ----------- $PVCNAME
 PV Name ------------ $PVNAME
 Target Zone -------- $TARGETZONE
 Volume Id ---------- $VOLUMEID
 Original Replicas -- $REPLICAS

EOF

read -p 'Press ENTER to continue'
echo

if [ $REPLICAS -gt 0 ]; then
    echo -n "Scaling down $DEPLOYMENTOBJ: $REPLICAS -> 0"
    oc -n $NAMESPACE scale --replicas=0 $DEPLOYMENTOBJ
    while [ "$(oc -n $NAMESPACE get $DEPLOYMENTOBJ --template={{.status.replicas}})" != "0" ]; do
        echo
    done

    while sleep 0.1; do
        echo
        oc -n $NAMESPACE get pod
        read -p "Press ENTER to continue" -t 3 || continue
        break
    done

fi

DESCRIPTION="snapshot-migration-${NAMESPACE}_${PVCNAME}_${VOLUMEID}"

echo -n "Creating snapshot... "
SNAPSHOTID=$(aws ec2  create-snapshot  --volume-id $VOLUMEID --description $DESCRIPTION --output text --query SnapshotId)
aws ec2 wait snapshot-completed --filter Name=snapshot-id,Values=$SNAPSHOTID
echo $SNAPSHOTID

echo -n "Creating volume... "
TAGSPEC="ResourceType=volume,Tags=[{Key=Name,Value=kubernetes-dynamic-$PVNAME},{Key=kubernetes.io/created-for/pv/name,Value=$PVNAME},{Key=kubernetes.io/created-for/pvc/name,Value=$PVCNAME},{Key=kubernetes.io/created-for/pvc/namespace,Value=$NAMESPACE}]"
VOLUMEID=$(aws ec2 create-volume \
    --availability-zone $TARGETZONE \
    --snapshot-id $SNAPSHOTID \
    --volume-type gp2 \
    --output text \
    --query VolumeId \
    --tag-specifications "$TAGSPEC")
echo $VOLUMEID

echo Updating $DEPLOYMENTOBJ...
oc label pv/$PVNAME failure-domain.beta.kubernetes.io/zone=$TARGETZONE --overwrite
oc patch -p "{\"spec\":{\"awsElasticBlockStore\":{\"volumeID\":\"aws://$TARGETZONE/$VOLUMEID\"}}}" pv/$PVNAME

if [ $REPLICAS -gt 0 ]; then
    echo "Scaling back $DEPLOYMENTOBJ: 0 -> $REPLICAS"
    oc -n $NAMESPACE scale --replicas=$REPLICAS $DEPLOYMENTOBJ
fi