Fix etcd script to delete other files when there is no space left on device

[24sama]

What type of PR is this?

/kind bug

What this PR does / why we need it:

Fix etcd script to delete other files when there is no space left on device.
There is a very extreme scenario but also very deadly, this script incorrectly deletes / directory files when the node does not have space to create a directory.

1. And for the existing cluster installed by kk, suggest manually editing the script:

$ vi /usr/local/bin/kube-scripts/etcd-backup.sh

2. modify the script like the below:
   1. add set -o xxx
   2. replace the : after the cd command with &&

#!/bin/bash

set -o errexit
set -o nounset
set -o pipefail

ETCDCTL_PATH='/usr/local/bin/etcdctl'
ENDPOINTS='https://192.168.100.3:2379'
ETCD_DATA_DIR="/var/lib/etcd"
BACKUP_DIR="/var/backups/kube_etcd/etcd-$(date +%Y-%m-%d-%H-%M-%S)"
KEEPBACKUPNUMBER='6'
ETCDBACKUPSCIPT='/usr/local/bin/kube-scripts'

ETCDCTL_CERT="/etc/ssl/etcd/ssl/admin-node1.pem"
ETCDCTL_KEY="/etc/ssl/etcd/ssl/admin-node1-key.pem"
ETCDCTL_CA_FILE="/etc/ssl/etcd/ssl/ca.pem"

[ ! -d $BACKUP_DIR ] && mkdir -p $BACKUP_DIR

export ETCDCTL_API=2;$ETCDCTL_PATH backup --data-dir $ETCD_DATA_DIR --backup-dir $BACKUP_DIR

sleep 3

{
export ETCDCTL_API=3;$ETCDCTL_PATH --endpoints="$ENDPOINTS" snapshot save $BACKUP_DIR/snapshot.db \
                                   --cacert="$ETCDCTL_CA_FILE" \
                                   --cert="$ETCDCTL_CERT" \
                                   --key="$ETCDCTL_KEY"
} > /dev/null 

sleep 3

cd $BACKUP_DIR/../ && ls -lt |awk '{if(NR > '$KEEPBACKUPNUMBER'){print "rm -rf "$9}}'|sh

3. reload the new script:

$ systemctl daemon-reload

Which issue(s) this PR fixes:

Fixes #

Special notes for reviewers:

Does this PR introduced a user-facing change?

Additional documentation, usage docs, etc.:

[ks-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: 24sama

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[pixiake]

/lgtm

[ks-ci-bot]

LGTM label has been added.

Git tree hash: 22864033defb2c9691ca295c8a0173cd0836a05e