Kubernetes-3.3:ETCD集群搭建及使用(https认证+数据备份恢复)
环境介绍
基于CentOS Linux release 7.9.2009 (Core)
ip | hostname | role |
---|---|---|
172.17.0.4 | cd782d0a790b | etcd1 |
172.17.0.3 | 83d43a1203f6 | etcd2 |
172.17.0.2 | 99dac45f202c | etcd3 |
## 先添加 yum 仓库
## docker-ce
yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
## epel
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
安装docker-ce
yum install -y yum-utils device-mapper-persistent-data lvm2 docker-ce
安装go,非必须(如果编译安装,则要有go环境)
yum install golang
其他
yum -y install ansible git iproute
开始构建etcd集群(yum 安装)
yum -y install etcd
## 查看版本
[root@cd782d0a790b data]# etcdctl -v
etcdctl version: 3.3.11
API version: 2
1、基于http协议构建集群
编辑配置文件
cat /etc/etcd/etcd.conf
## etcd存储路径
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
## 用于监听集群内所有etcd通讯的URL列表
ETCD_LISTEN_PEER_URLS="http://172.17.0.4:2380"
## 用于监听客户端通讯的URL列表
ETCD_LISTEN_CLIENT_URLS="http://172.17.0.4:2379,http://127.0.0.1:2379"
## 集群名字
ETCD_NAME="etcd1"
## 触发快照到硬盘的已提交事务的数量
ETCD_SNAPSHOT_COUNT="10000"
## 心跳间隔时间,单位毫秒
ETCD_HEARTBEAT_INTERVAL="250"
## 选举的超时时间,单位毫秒
ETCD_ELECTION_TIMEOUT="5000"
## 列出本机的通信 URL 以便通告给集群的其他成员
ETCD_INITIAL_ADVERTISE_PEER_URLS="http://172.17.0.4:2380"
## 列出本机的客户端连接URL,通告给集群中的其他成员
ETCD_ADVERTISE_CLIENT_URLS="http://172.17.0.4:2379"
## 启动初始化集群配置
ETCD_INITIAL_CLUSTER="etcd1=http://172.17.0.4:2380,etcd2=http://172.17.0.3:2380,etcd3=http://172.17.0.2:2380"
## 在启动期间用于 etcd 集群的初始化集群记号
ETCD_INITIAL_CLUSTER_TOKEN="k8s_etcd"
## 初始化集群状态,一般在新创建集群时填new,如果是加入某个已有的集群,则填写existing
ETCD_INITIAL_CLUSTER_STATE="new"
## 代理模式设置
ETCD_PROXY="off"
## 是否开始自动压缩,0表示关闭自动压缩。
ETCD_AUTO_COMPACTION_RETENTION="8"
## METRICS接口,用于提供给监控对接的
ETCD_METRICS="basic"
注意:三个配置文件大体内容基本相似,需要注意的是ETCD_NAME和本机的ip地址要随之更改
加入systemctl管理
cat /usr/lib/systemd/system/etcd.service
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target
[Service]
Type=notify
WorkingDirectory=/var/lib/etcd/
EnvironmentFile=-/etc/etcd/etcd.conf
User=etcd
# set GOMAXPROCS to number of processors
ExecStart=/bin/bash -c "GOMAXPROCS=$(nproc) /usr/bin/etcd --name=\"${ETCD_NAME}\" --data-dir=\"${ETCD_DATA_DIR}\" --listen-client-urls=\"${ETCD_LISTEN_CLIENT_URLS}\""
Restart=on-failure
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
启动服务,检查健康状态
## 三台都启动
systemctl start etcd
## 查看集群
[root@cd782d0a790b /]# etcdctl member list
d02233d35f3c4b94: name=etcd3 peerURLs=http://172.17.0.2:2380 clientURLs=http://172.17.0.2:2379 isLeader=false
e302fd1dad15f911: name=etcd1 peerURLs=http://172.17.0.4:2380 clientURLs=http://172.17.0.4:2379 isLeader=true
ef7057d9f69d96ad: name=etcd2 peerURLs=http://172.17.0.3:2380 clientURLs=http://172.17.0.3:2379 isLeader=false
## 检查健康状态
[root@cd782d0a790b /]# etcdctl cluster-health
member d02233d35f3c4b94 is healthy: got healthy result from http://172.17.0.2:2379
member e302fd1dad15f911 is healthy: got healthy result from http://172.17.0.4:2379
member ef7057d9f69d96ad is healthy: got healthy result from http://172.17.0.3:2379
以上为默认的 API version: 2,可以将 API version 改为 3,再次查看
export ETCDCTL_API=3
HOST_1=172.17.0.2
HOST_2=172.17.0.3
HOST_3=172.17.0.4
ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379
## 查看list
[root@cd782d0a790b /]# etcdctl --endpoints=$ENDPOINTS member list
d02233d35f3c4b94, started, etcd3, http://172.17.0.2:2380, http://172.17.0.2:2379
e302fd1dad15f911, started, etcd1, http://172.17.0.4:2380, http://172.17.0.4:2379
ef7057d9f69d96ad, started, etcd2, http://172.17.0.3:2380, http://172.17.0.3:2379
## 检查health
[root@cd782d0a790b /]# etcdctl --endpoints=$ENDPOINTS endpoint health
172.17.0.2:2379 is healthy: successfully committed proposal: took = 7.5093ms
172.17.0.4:2379 is healthy: successfully committed proposal: took = 5.5682ms
172.17.0.3:2379 is healthy: successfully committed proposal: took = 8.0291ms
## 查看status
[root@cd782d0a790b /]# etcdctl --write-out=table --endpoints=$ENDPOINTS endpoint status
+-----------------+------------------+---------+---------+-----------+-----------+------------+
| ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+-----------------+------------------+---------+---------+-----------+-----------+------------+
| 172.17.0.2:2379 | d02233d35f3c4b94 | 3.3.11 | 16 kB | false | 129 | 12 |
| 172.17.0.3:2379 | ef7057d9f69d96ad | 3.3.11 | 16 kB | false | 129 | 12 |
| 172.17.0.4:2379 | e302fd1dad15f911 | 3.3.11 | 20 kB | true | 129 | 12 |
+-----------------+------------------+---------+---------+-----------+-----------+------------+
具体更多操作可以查看etcd官网demo:https://etcd.io/docs/v3.4/demo/
2、基于https构建集群
首先需要生成证书,下载证书生成工具
curl -s -L -o /usr/local/bin/cfssl https://pkg.cfssl.org/R1.2/cfssl_linux-amd64
curl -s -L -o /usr/local/bin/cfssljson https://pkg.cfssl.org/R1.2/cfssljson_linux-amd64
curl -s -L -o /usr/local/bin/cfssl-certinfo https://pkg.cfssl.org/R1.2/cfssl-certinfo_linux-amd64
chmod +x /usr/local/bin/cfssl*
开始生成证书
## CA机构配置,有效期10年
[root@cd782d0a790b cert]# cat > ca-config.json << EOF
{
"signing": {
"default": {
"expiry": "87600h"
},
"profiles": {
"etcd": {
"expiry": "87600h",
"usages": [
"signing",
"key encipherment",
"server auth",
"client auth"
]
}
}
}
}
EOF
"字段说明"
"ca-config.json":可以定义多个 profiles,分别指定不同的过期时间、使用场景等参数;后续在签名证书时使用某个 profile;
"signing":表示该证书可用于签名其它证书;生成的 ca.pem 证书中 CA=TRUE;
"server auth":表示client可以用该 CA 对server提供的证书进行验证;
"client auth":表示server可以用该 CA 对client提供的证书进行验证;
## CA机构配置,机构名称Comman Name,所在地Country国家, State省, Locality市
[root@cd782d0a790b cert]# cat > ca-csr.json << EOF
{
"CN": "etcd CA",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "CN",
"ST": "Beijing",
"L": "Beijing"
}
]
}
EOF
## 向ca机构申请:证书注册 (中国,北京省,北京市),每个节点用相同的证书,所以要填写所有主机ip
[root@cd782d0a790b cert]# cat > server-csr.json << EOF
{
"CN": "etcd",
"hosts": [
"172.17.0.2",
"172.17.0.3",
"172.17.0.4"
],
"names": [
{
"C": "CN",
"ST": "BeiJing",
"L": "BeiJing",
"O":"aa.com",
"CN":"beijing.aa.com"
}
]
}
EOF
请求文件全部编辑好后:
## 生成ca证书和key
cfssl gencert -initca ca-csr.json | cfssljson -bare ca -
## 生成etcd证书和key,注意这里的-profile的值必须和ca-config中的profiles的值一样
cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=etcd server-csr.json | cfssljson -bare server
## 生成证书如下
[root@cd782d0a790b ssl]# ls *.pem
ca-key.pem ca.pem server-key.pem server.pem
## 赋值读权限
chmod 644 *.pem
以上情况是客户端、服务端、集群内peer通信都是用同一个证书,实际情况中,可以把它分为多个,设置不同的功能,不同的到期时间,例如如下:
## ca证书生成,在此定义了几种不同的证书类型
[root@cd782d0a790b cert]# cat > ca-config.json << EOF
{
"signing": {
"default": {
"expiry": "168h"
},
"profiles": {
"server": {
"expiry": "8760h",
"usages": [
"signing",
"key encipherment",
"server auth"
]
},
"client": {
"expiry": "8760h",
"usages": [
"signing",
"key encipherment",
"client auth"
]
},
"peer": {
"expiry": "8760h",
"usages": [
"signing",
"key encipherment",
"server auth",
"client auth"
]
}
}
}
}
EOF
"类型说明"
在其中定义3个profile
"server" 作为服务器与客户端通信时的服务器证书
"client" 作为服务器与客户端通信时的客户端证书
"peer" 作为服务器间通信时用的证书,既认证服务器也认证客户端
cat > ca-csr.json << EOF
{
"CN": "etcd CA",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "CN",
"ST": "Beijing",
"L": "Beijing"
}
]
}
EOF
## 这种是单独的,各自使用自己的peer证书,注意名字要不同,所有的机器都要执行一次
[root@cd782d0a790b cert]# cat > etcd1-csr.json << EOF
{
"CN": "etcd1",
"hosts": [
"172.17.0.2"
],
"names": [
{
"C": "CN",
"ST": "BeiJing",
"L": "BeiJing",
"O":"aa.com",
"CN":"beijing.aa.com"
}
]
}
EOF
请求文件全部编辑好后:
## 生成ca证书和key
cfssl gencert -initca ca-csr.json | cfssljson -bare ca -
## 生成etcd证书和key,注意这里的-profile的值必须和ca-config中的profiles的值一样
for i in `seq 1 5`;do cfssl gencert -ca=ca.pem -ca-key=ca-key.pem -config=ca-config.json -profile=peer etcd${i}-csr.json | cfssljson -bare etcd${i};done
[root@cd782d0a790b ssl]# ls
ca-config.json ca.csr etcd1-key.pem etcd2-csr.json etcd2.pem etcd3.csr etcd4-key.pem etcd5-csr.json etcd5.pem
ca-csr.json ca.pem etcd1.csr etcd2-key.pem etcd3-csr.json etcd3.pem etcd4.csr etcd5-key.pem server.pem
ca-key.pem etcd1-csr.json etcd1.pem etcd2.csr etcd3-key.pem etcd4-csr.json etcd4.pem etcd5.csr
## 赋值读权限
chmod 644 *.pem
如果是每个服务器单独的证书,下边etcd的配置,包括查看、检查状态时,所指定的证书,都指定本机的即可
修改etcd.conf配置
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://172.17.0.4:2380"
ETCD_LISTEN_CLIENT_URLS="https://172.17.0.4:2379,https://127.0.0.1:2379"
ETCD_NAME="etcd1"
ETCD_SNAPSHOT_COUNT="10000"
ETCD_HEARTBEAT_INTERVAL="250"
ETCD_ELECTION_TIMEOUT="5000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://172.17.0.4:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://172.17.0.4:2379"
ETCD_INITIAL_CLUSTER="etcd1=https://172.17.0.4:2380,etcd2=https://172.17.0.3:2380,etcd3=https://172.17.0.2:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd"
ETCD_INITIAL_CLUSTER_STATE="new"
ETCD_PROXY="off"
## etcd 客户端与服务端通信的证书和key
ETCD_CERT_FILE="/data/cert/ssl/etcd1.pem"
ETCD_KEY_FILE="/data/cert/ssl/etcd1-key.pem"
ETCD_CLIENT_CERT_AUTH="true"
## ca证书
ETCD_TRUSTED_CA_FILE="/data/cert/ssl/ca.pem"
## etcd 集群内部通信证书和key
ETCD_PEER_CERT_FILE="/data/cert/ssl/etcd1.pem"
ETCD_PEER_KEY_FILE="/data/cert/ssl/etcd1-key.pem"
ETCD_PEER_CLIENT_CERT_AUTH="true"
ETCD_PEER_TRUSTED_CA_FILE="/data/cert/ssl/ca.pem"
ETCD_AUTO_COMPACTION_RETENTION="8"
ETCD_METRICS="basic"
将http全部更改为https,然后指定证书的路径的路径
重启服务
systemctl restart etcd
## 重启时,报类似错误
request sent was ignored (cluster ID mismatch: peer[61c68880c0fd8e67]=47ca0413c1aaf745, local=755bf44e2e1770ae)
或
publish error: etcdserver: request timed out
## 因为之前启动过http的etcd集群,已经有数据保存,由于这些脏数据引起的,所有节点全部数据删除后,重启即可
rm -rf /var/lib/etcd/default.etcd/*
检查状态
export ETCDCTL_API=3
HOST_1=https://172.17.0.2
HOST_2=https://172.17.0.3
HOST_3=https://172.17.0.4
ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379
## list
etcdctl --endpoints=$ENDPOINTS --cacert="/data/cert/ssl/ca.pem" --cert="/data/cert/ssl/etcd1.pem" --key="/data/cert/ssl/etcd1-key.pem" member list --write-out=table
+------------------+---------+-------+-------------------------+-------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+------------------+---------+-------+-------------------------+-------------------------+
| 37ab29a4575d84d2 | started | etcd3 | https://172.17.0.2:2380 | https://172.17.0.2:2379 |
| 3e6a29fd4717a78b | started | etcd2 | https://172.17.0.3:2380 | https://172.17.0.3:2379 |
| 653155eddc689793 | started | etcd1 | https://172.17.0.4:2380 | https://172.17.0.4:2379 |
+------------------+---------+-------+-------------------------+-------------------------+
## status
etcdctl --endpoints=$ENDPOINTS --cacert="/data/cert/ssl/ca.pem" --cert="/data/cert/ssl/etcd1.pem" --key="/data/cert/ssl/etcd1-key.pem" endpoint status --write-out=table
+-------------------------+------------------+---------+---------+-----------+-----------+------------+
| ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+-------------------------+------------------+---------+---------+-----------+-----------+------------+
| https://172.17.0.2:2379 | 37ab29a4575d84d2 | 3.3.11 | 20 kB | false | 1064 | 139 |
| https://172.17.0.3:2379 | 3e6a29fd4717a78b | 3.3.11 | 20 kB | true | 1064 | 139 |
| https://172.17.0.4:2379 | 653155eddc689793 | 3.3.11 | 20 kB | false | 1064 | 139 |
+-------------------------+------------------+---------+---------+-----------+-----------+------------+
3、ETCD集群中添加节点
member add 添加
## add
etcdctl --endpoints=$ENDPOINTS --cacert="/data/cert/ssl/ca.pem" --cert="/data/cert/ssl/etcd1.pem" --key="/data/cert/ssl/etcd1-key.pem" member add etcd4 --peer-urls=https://172.17.0.5:2380
Member 71f4582f1c4ba901 added to cluster a89c967de8e14b61
ETCD_NAME="etcd4"
ETCD_INITIAL_CLUSTER="etcd3=https://172.17.0.2:2380,etcd2=https://172.17.0.3:2380,etcd1=https://172.17.0.4:2380,etcd4=https://172.17.0.5:2380"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://172.17.0.5:2380"
ETCD_INITIAL_CLUSTER_STATE="existing"
## list
etcdctl --endpoints=$ENDPOINTS --cacert="/data/cert/ssl/ca.pem" --cert="/data/cert/ssl/etcd1.pem" --key="/data/cert/ssl/etcd1-key.pem" member list --write-out=table
+------------------+-----------+-------+-------------------------+-------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+------------------+-----------+-------+-------------------------+-------------------------+
| 37ab29a4575d84d2 | started | etcd3 | https://172.17.0.2:2380 | https://172.17.0.2:2379 |
| 3e6a29fd4717a78b | started | etcd2 | https://172.17.0.3:2380 | https://172.17.0.3:2379 |
| 653155eddc689793 | started | etcd1 | https://172.17.0.4:2380 | https://172.17.0.4:2379 |
| e321a980939fe867 | unstarted | | https://172.17.0.5:2380 | |
+------------------+-----------+-------+-------------------------+-------------------------+
注意:添加节点时,必须把集群状态修复完毕,才能继续添加下一个,否则报错类似:Error: etcdserver: unhealthy cluster
最终etcd4的配置文件如下
ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
ETCD_LISTEN_PEER_URLS="https://172.17.0.5:2380"
ETCD_LISTEN_CLIENT_URLS="https://172.17.0.5:2379,https://127.0.0.1:2379"
ETCD_NAME="etcd4"
ETCD_SNAPSHOT_COUNT="10000"
ETCD_HEARTBEAT_INTERVAL="250"
ETCD_ELECTION_TIMEOUT="5000"
ETCD_INITIAL_ADVERTISE_PEER_URLS="https://172.17.0.5:2380"
ETCD_ADVERTISE_CLIENT_URLS="https://172.17.0.5:2379"
ETCD_INITIAL_CLUSTER="etcd1=https://172.17.0.4:2380,etcd2=https://172.17.0.3:2380,etcd3=https://172.17.0.2:2380,etcd4=https://172.17.0.5:2380"
ETCD_INITIAL_CLUSTER_TOKEN="etcd"
ETCD_INITIAL_CLUSTER_STATE="existing"
ETCD_PROXY="off"
ETCD_CERT_FILE="/data/cert/ssl/etcd4.pem"
ETCD_KEY_FILE="/data/cert/ssl/etcd4-key.pem"
ETCD_CLIENT_CERT_AUTH="true"
ETCD_TRUSTED_CA_FILE="/data/cert/ssl/ca.pem"
ETCD_PEER_CERT_FILE="/data/cert/ssl/etcd4.pem"
ETCD_PEER_KEY_FILE="/data/cert/ssl/etcd4-key.pem"
ETCD_PEER_CLIENT_CERT_AUTH="true"
ETCD_PEER_TRUSTED_CA_FILE="/data/cert/ssl/ca.pem"
ETCD_AUTO_COMPACTION_RETENTION="8"
ETCD_METRICS="basic"
启动etcd4,查看集群状态
systemctl start etcd
export ETCDCTL_API=3
HOST_1=https://172.17.0.2
HOST_2=https://172.17.0.3
HOST_3=https://172.17.0.4
HOST_4=https://172.17.0.5
ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379,$HOST_4:2379
## list
etcdctl --endpoints=$ENDPOINTS --cacert="/data/cert/ssl/ca.pem" --cert="/data/cert/ssl/etcd1.pem" --key="/data/cert/ssl/etcd1-key.pem" member list --write-out=table
+------------------+---------+-------+-------------------------+-------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+------------------+---------+-------+-------------------------+-------------------------+
| 37ab29a4575d84d2 | started | etcd3 | https://172.17.0.2:2380 | https://172.17.0.2:2379 |
| 3e6a29fd4717a78b | started | etcd2 | https://172.17.0.3:2380 | https://172.17.0.3:2379 |
| 653155eddc689793 | started | etcd1 | https://172.17.0.4:2380 | https://172.17.0.4:2379 |
| e321a980939fe867 | started | etcd4 | https://172.17.0.5:2380 | https://172.17.0.5:2379 |
+------------------+---------+-------+-------------------------+-------------------------+
## status
etcdctl --endpoints=$ENDPOINTS --cacert="/data/cert/ssl/ca.pem" --cert="/data/cert/ssl/etcd1.pem" --key="/data/cert/ssl/etcd1-key.pem" endpoint status --write-out=table
+-------------------------+------------------+---------+---------+-----------+-----------+------------+
| ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+-------------------------+------------------+---------+---------+-----------+-----------+------------+
| https://172.17.0.2:2379 | 37ab29a4575d84d2 | 3.3.11 | 20 kB | false | 1066 | 159 |
| https://172.17.0.3:2379 | 3e6a29fd4717a78b | 3.3.11 | 20 kB | false | 1066 | 159 |
| https://172.17.0.4:2379 | 653155eddc689793 | 3.3.11 | 20 kB | true | 1066 | 159 |
| https://172.17.0.5:2379 | e321a980939fe867 | 3.3.11 | 20 kB | false | 1066 | 159 |
+-------------------------+------------------+---------+---------+-----------+-----------+------------+
4、备份及恢复ETCD集群数据
备份
## 环境配置
export ETCDCTL_API=3
kubectl get nodes -o wide
HOST_1=https://10.36.234.169
HOST_2=https://10.36.234.180
HOST_3=https://10.36.235.19
ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379
## 备份
etcdctl --endpoints=$ENDPOINTS --cacert="/etc/ssl/etcd/ssl/ca.pem" --cert="/etc/ssl/etcd/ssl/member-gzbh-intelmbx043.gzbh.baidu.com.pem" --key="/etc/ssl/etcd/ssl/member-gzbh-intelmbx043.gzbh.baidu.com-key.pem" snapshot save my.db
Snapshot saved at my.db
## 查看
[root@gzbh-intelmbx043 etcd_data]# ls
my.db
恢复
## 停止etcd服务
systemctl stop etcd
## 删除原数据(如原数据重要,记得备份!)
rm -rf /var/lib/etcd
## 恢复,如果是多台机器集群模式,每个机器都要导入
etcdctl --endpoints=https://10.61.187.39:2379 --cacert="/etc/ssl/etcd/ssl/ca.pem" --cert="/etc/ssl/etcd/ssl/member-yq01-aip-aikefu06e1a866.yq01.baidu.com.pem" --key="/etc/ssl/etcd/ssl/member-yq01-aip-aikefu06e1a866.yq01.baidu.com-key.pem" snapshot restore my.db --name=etcd1 --initial-cluster etcd1=https://10.61.187.39:2380 --initial-cluster-token etcd_test --initial-advertise-peer-urls https://10.61.187.39:2380 --data-dir=/var/lib/etcd/
2021-05-25 16:05:02.784608 I | mvcc: restore compact to 6104817
2021-05-25 16:05:02.802119 I | etcdserver/membership: added member 67745b5848ce7e3c [https://10.61.187.39:2380] to cluster 1256ee7f1ba66254
## 启动服务即可
systemctl start etcd
需要注意:数据的备份和恢复是个敏感操作,一定要谨慎!