mirror of https://github.com/k3s-io/k3s
Merge pull request #34696 from wojtek-t/restore_etcd_from_backup
Automatic merge from submit-queue Restore etcd from backup The new script performs disaster recovery of etcd from backup. https://github.com/kubernetes/kubernetes/issues/20504 @alex-mohr @lavalamp @kubernetes/goog-gkepull/6/head
Kubernetes Submit Queue
GitHub
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#!/bin/bash
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# Copyright 2016 The Kubernetes Authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# This script performs disaster recovery of etcd from the backup data.
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# Assumptions:
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# - backup was done using etcdctl command:
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# a) in case of etcd2
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# $ etcdctl backup --data-dir=<dir>
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# produced .snap and .wal files
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# b) in case of etcd3
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# $ etcdctl --endpoints=<address> snapshot save
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# produced .db file
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# - version.txt file is in the current directy (if it isn't it will be
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# defaulted to "2.2.1/etcd2"). Based on this file, the script will
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# decide to which version we are restoring (procedures are different
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# for etcd2 and etcd3).
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# - in case of etcd2 - *.snap and *.wal files are in current directory
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# - in case of etcd3 - *.db file is in the current directory
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# - the script is run as root
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#
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# The script doesn't support restoring event etcd.
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set -o errexit
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set -o nounset
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set -o pipefail
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# Version file contains information about current version in the format:
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# <etcd binary version>/<etcd api mode> (e.g. "3.0.12/etcd3").
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#
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# If the file doesn't exist we assume "2.2.1/etcd2" configuration is
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# the current one and create a file with such configuration.
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# The restore procedure is chosen based on this information.
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VERSION_FILE="version.txt"
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if [ ! -f "${VERSION_FILE}" ]; then
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echo "2.2.1/etcd2" > "${VERSION_FILE}"
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fi
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VERSION_CONTENTS="$(cat ${VERSION_FILE})"
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ETCD_VERSION="$(echo $VERSION_CONTENTS | cut -d '/' -f 1)"
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ETCD_API="$(echo $VERSION_CONTENTS | cut -d '/' -f 2)"
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# Name is used only in case of etcd3 mode, to appropriate set the metadata
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# for the etcd data.
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# NOTE: NAME HAS TO BE EQUAL TO WHAT WE USE IN --name flag when starting etcd.
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NAME="${NAME:-etcd-$(hostname)}"
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# Port on which etcd is exposed.
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etcd_port=2379
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event_etcd_port=4002
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# Wait until both etcd instances are up
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wait_for_etcd_up() {
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port=$1
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# TODO: As of 3.0.x etcd versions, all 2.* and 3.* versions return
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# {"health": "true"} on /health endpoint in healthy case.
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# However, we should come with a regex for it to avoid future break.
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health_ok="{\"health\": \"true\"}"
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for i in $(seq 120); do
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# TODO: Is it enough to look into /health endpoint?
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health=$(curl --silent http://127.0.0.1:${port}/health)
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if [ "${health}" == "${health_ok}" ]; then
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return 0
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fi
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sleep 1
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done
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return 1
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}
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# Wait until apiserver is up.
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wait_for_cluster_healthy() {
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for i in $(seq 120); do
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cs_status=$(kubectl get componentstatuses -o template --template='{{range .items}}{{with index .conditions 0}}{{.type}}:{{.status}}{{end}}{{"\n"}}{{end}}') || true
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componentstatuses=$(echo "${cs_status}" | grep -c 'Healthy:') || true
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healthy=$(echo "${cs_status}" | grep -c 'Healthy:True') || true
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if [ "${componentstatuses}" -eq "${healthy}" ]; then
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return 0
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fi
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sleep 1
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done
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return 1
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}
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# Wait until etcd and apiserver pods are down.
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wait_for_etcd_and_apiserver_down() {
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for i in $(seq 120); do
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etcd=$(docker ps | grep etcd | grep -v etcd-empty-dir | wc -l)
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apiserver=$(docker ps | grep apiserver | wc -l)
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# TODO: Theoretically it is possible, that apiserver and or etcd
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# are currently down, but Kubelet is now restarting them and they
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# will reappear again. We should avoid it.
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if [ "${etcd}" -eq "0" -a "${apiserver}" -eq "0" ]; then
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return 0
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fi
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sleep 1
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done
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return 1
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}
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# Move the manifest files to stop etcd and kube-apiserver
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# while we swap the data out from under them.
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MANIFEST_DIR="/etc/kubernetes/manifests"
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MANIFEST_BACKUP_DIR="/etc/kubernetes/manifests-backups"
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mkdir -p "${MANIFEST_BACKUP_DIR}"
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# If those files were already moved (e.g. during previous
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# try of backup) don't fail on it.
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mv "${MANIFEST_DIR}/kube-apiserver.manifest" "${MANIFEST_BACKUP_DIR}" || true
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mv "${MANIFEST_DIR}/etcd.manifest" "${MANIFEST_BACKUP_DIR}" || true
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mv "${MANIFEST_DIR}/etcd-events.manifest" "${MANIFEST_BACKUP_DIR}" || true
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# Wait for the pods to be stopped
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echo "Waiting for etcd and kube-apiserver to be down"
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if ! wait_for_etcd_and_apiserver_down; then
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# Couldn't kill etcd and apiserver.
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echo "Downing etcd and apiserver failed"
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exit 1
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fi
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# Create the sort of directory structure that etcd expects.
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# If this directory already exists, remove it.
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BACKUP_DIR="/var/tmp/backup"
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rm -rf "${BACKUP_DIR}"
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if [ "${ETCD_API}" == "etcd2" ]; then
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echo "Preparing etcd backup data for restore"
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# In v2 mode, we simply copy both snap and wal files to a newly created
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# directory. After that, we start etcd with --force-new-cluster option
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# that (according to the etcd documentation) is required to recover from
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# a backup.
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mkdir -p "${BACKUP_DIR}/member/snap"
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mkdir -p "${BACKUP_DIR}/member/wal"
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# If the cluster is relatively new, there can be no .snap file.
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mv *.snap "${BACKUP_DIR}/member/snap/" || true
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mv *.wal "${BACKUP_DIR}/member/wal/"
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# TODO(jsz): This won't work with HA setups (e.g. do we need to set --name flag)?
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image=$(docker run -d -v ${BACKUP_DIR}:/var/etcd/data \
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--net=host -p ${etcd_port}:${etcd_port} \
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"gcr.io/google_containers/etcd:${ETCD_VERSION}" /bin/sh -c \
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"/usr/local/bin/etcd --data-dir /var/etcd/data --force-new-cluster")
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if [ "$?" -ne "0" ]; then
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echo "Docker container didn't started correctly"
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exit 1
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fi
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if ! wait_for_etcd_up "${etcd_port}"; then
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echo "Etcd didn't come back correctly"
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exit 1
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fi
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# Kill that etcd instance.
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docker kill "${image}"
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elif [ "${ETCD_API}" == "etcd3" ]; then
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echo "Preparing etcd snapshot for restore"
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mkdir -p "${BACKUP_DIR}"
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number_files=$(find . -maxdepth 1 -type f -name "*.db" | wc -l)
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if [ "${number_files}" -ne "1" ]; then
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echo "Incorrect number of *.db files - expected 1"
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exit 1
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fi
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mv *.db "${BACKUP_DIR}/"
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snapshot="$(ls ${BACKUP_DIR})"
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# Run etcdctl snapshot restore command and wait until it is finished.
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# setting with --name in the etcd manifest file and then it seems to work.
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# TODO(jsz): This command may not work in case of HA.
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image=$(docker run -d -v ${BACKUP_DIR}:/var/tmp/backup --env ETCDCTL_API=3 \
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"gcr.io/google_containers/etcd:${ETCD_VERSION}" /bin/sh -c \
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"/usr/local/bin/etcdctl snapshot restore ${BACKUP_DIR}/${snapshot} --name ${NAME} --initial-cluster ${NAME}=http://localhost:2380; mv /${NAME}.etcd/member /var/tmp/backup/")
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if [ "$?" -ne "0" ]; then
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echo "Docker container didn't started correctly"
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exit 1
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fi
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echo "Prepare container exit code: $(docker wait ${image})"
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rm -f "${BACKUP_DIR}/${snapshot}"
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fi
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# Also copy version.txt file.
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cp "${VERSION_FILE}" "${BACKUP_DIR}"
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# Find out if we are running GCI vs CVM.
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export CVM=$(curl "http://metadata/computeMetadata/v1/instance/attributes/" -H "Metadata-Flavor: Google" |& grep -q gci; echo $?)
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if [[ "$CVM" == "1" ]]; then
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export MNT_DISK="/mnt/master-pd"
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else
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export MNT_DISK="/mnt/disks/master-pd"
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fi
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# Save the corrupted data (clean directory if it is already non-empty).
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rm -rf "${MNT_DISK}/var/etcd-corrupted"
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mkdir -p "${MNT_DISK}/var/etcd-corrupted"
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mv /var/etcd/data "${MNT_DISK}/var/etcd-corrupted"
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# Replace the corrupted data dir with the resotred data.
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mv "${BACKUP_DIR}" /var/etcd/data
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# Start etcd and kube-apiserver again.
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echo "Restarting etcd and apiserver from restored snapshot"
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mv "${MANIFEST_BACKUP_DIR}"/* "${MANIFEST_DIR}/"
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rm -rf "${MANIFEST_BACKUP_DIR}"
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# Verify that etcd is back.
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echo "Waiting for etcd to come back"
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if ! wait_for_etcd_up "${etcd_port}"; then
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echo "Etcd didn't come back correctly"
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exit 1
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fi
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# Verify that event etcd is back.
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echo "Waiting for event etcd to come back"
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if ! wait_for_etcd_up "${event_etcd_port}"; then
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echo "Event etcd didn't come back correctly"
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exit 1
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fi
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# Verify that kube-apiserver is back and cluster is healthy.
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echo "Waiting for apiserver to come back"
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if ! wait_for_cluster_healthy; then
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echo "Apiserver didn't come back correctly"
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exit 1
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fi
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echo "Cluster successfully restored!"
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