K8S集群中etcd备份及恢复【转】

etcd是kubernetes集群极为重要的一块服务，存储了kubernetes集群所有的数据信息，如Namespace、Pod、Service、路由等状态信息。如果etcd集群发生灾难或者 etcd 集群数据丢失，都会影响k8s集群数据的恢复。因此，通过备份etcd数据来实现kubernetes集群的灾备环境十分重要。

 

一、etcd集群备份

etcd不同版本的 etcdctl 命令不一样，但大致差不多，这里备份使用 napshot save进行快照备份。

需要注意几点：

• 备份操作在etcd集群的其中一个节点执行就可以。
• 这里使用的是etcd v3的api，因为从 k8s 1.13 开始，k8s不再支持 v2 版本的 etcd，即k8s的集群数据都存在了v3版本的etcd中。故备份的数据也只备份了使用v3添加的etcd数据，v2添加的etcd数据是没有做备份的。
• 本案例使用的是二进制部署的k8s v1.18.6 + Calico 容器环境（下面命令中的"ETCDCTL_API=3 etcdctl" 等同于 "etcdctl"）

 

1）开始备份之前，先来查看下etcd数据

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etcd 数据目录 [root@k8s-master01 ~] # cat /opt/k8s/bin/environment.sh |grep "ETCD_DATA_DIR=" export  ETCD_DATA_DIR= "/data/k8s/etcd/data"        etcd WAL 目录 [root@k8s-master01 ~] # cat /opt/k8s/bin/environment.sh |grep "ETCD_WAL_DIR=" export  ETCD_WAL_DIR= "/data/k8s/etcd/wal"   [root@k8s-master01 ~] # ls /data/k8s/etcd/data/ member [root@k8s-master01 ~] # ls /data/k8s/etcd/data/member/ snap [root@k8s-master01 ~] # ls /data/k8s/etcd/wal/ 0000000000000000-0000000000000000.wal  0.tmp

　　

2）执行etcd集群数据备份

在etcd集群的其中一个节点执行备份操作，然后将备份文件拷贝到其他节点上。

 

先在etcd集群的每个节点上创建备份目录

1	# mkdir -p /data/etcd_backup_dir

在etcd集群其中个一个节点（这里在k8s-master01）上执行备份：

1	[root@k8s-master01 ~] # ETCDCTL_API=3 etcdctl --cacert=/etc/kubernetes/cert/ca.pem --cert=/etc/etcd/cert/etcd.pem --key=/etc/etcd/cert/etcd-key.pem --endpoints=https://172.16.60.231:2379 snapshot save /data/etcd_backup_dir/etcd-snapshot-`date +%Y%m%d`.db

将备份文件拷贝到其他的etcd节点

1 2	[root@k8s-master01 ~] # rsync -e "ssh -p22" -avpgolr /data/etcd_backup_dir/etcd-snapshot-20200820.db root@k8s-master02:/data/etcd_backup_dir/ [root@k8s-master01 ~] # rsync -e "ssh -p22" -avpgolr /data/etcd_backup_dir/etcd-snapshot-20200820.db root@k8s-master03:/data/etcd_backup_dir/

　　

可以将上面k8s-master01节点的etcd备份命令放在脚本里，结合crontab进行定时备份：

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[root@k8s-master01 ~] # cat /data/etcd_backup_dir/etcd_backup.sh #!/usr/bin/bash   date ; CACERT= "/etc/kubernetes/cert/ca.pem" CERT= "/etc/etcd/cert/etcd.pem" EKY= "/etc/etcd/cert/etcd-key.pem" ENDPOINTS= "172.16.60.231:2379"   ETCDCTL_API=3  /opt/k8s/bin/etcdctl  \ --cacert= "${CACERT}"  --cert= "${CERT}"  --key= "${EKY}"  \ --endpoints=${ENDPOINTS} \ snapshot save  /data/etcd_backup_dir/etcd-snapshot- ` date  +%Y%m%d`.db   # 备份保留30天 find  /data/etcd_backup_dir/  -name  "*.db"  -mtime +30 - exec  rm  -f {} \;   # 同步到其他两个etcd节点 /bin/rsync  -e  "ssh -p5522"  -avpgolr --delete  /data/etcd_backup_dir/  root@k8s-master02: /data/etcd_backup_dir/ /bin/rsync  -e  "ssh -p5522"  -avpgolr --delete  /data/etcd_backup_dir/  root@k8s-master03: /data/etcd_backup_dir/

　　

设置crontab定时备份任务，每天凌晨5点执行备份：

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[root@k8s-master01 ~] # chmod 755 /data/etcd_backup_dir/etcd_backup.sh [root@k8s-master01 ~] # crontab -l #etcd集群数据备份 0 5 * * *  /bin/bash  -x  /data/etcd_backup_dir/etcd_backup .sh >  /dev/null  2>&1

二、etcd集群恢复

etcd集群备份操作只需要在其中的一个etcd节点上完成，然后将备份文件拷贝到其他节点。
但etcd集群恢复操作必须要所有的etcd节点上完成！

1）模拟etcd集群数据丢失
删除三个etcd集群节点的data数据 (或者直接删除data目录)

1	# rm -rf /data/k8s/etcd/data/*

 

查看k8s集群状态：

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[root@k8s-master01 ~] # kubectl get cs NAME                 STATUS      MESSAGE                                                                                           ERROR etcd-2               Unhealthy   Get https: //172 .16.60.233:2379 /health : dial tcp 172.16.60.233:2379: connect: connection refused etcd-1               Unhealthy   Get https: //172 .16.60.232:2379 /health : dial tcp 172.16.60.232:2379: connect: connection refused etcd-0               Unhealthy   Get https: //172 .16.60.231:2379 /health : dial tcp 172.16.60.231:2379: connect: connection refused scheduler            Healthy     ok controller-manager   Healthy     ok

　　

由于此时etcd集群的三个节点服务还在，过一会儿查看集群状态恢复正常：

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[root@k8s-master01 ~] # kubectl get cs NAME                 STATUS    MESSAGE             ERROR controller-manager   Healthy   ok scheduler            Healthy   ok etcd-0               Healthy   { "health" : "true" } etcd-2               Healthy   { "health" : "true" } etcd-1               Healthy   { "health" : "true" }   [root@k8s-master01 ~] # ETCDCTL_API=3 etcdctl --endpoints="https://172.16.60.231:2379,https://172.16.60.232:2379,https://172.16.60.233:2379" --cert=/etc/etcd/cert/etcd.pem --key=/etc/etcd/cert/etcd-key.pem --cacert=/etc/kubernetes/cert/ca.pem endpoint health https: //172 .16.60.231:2379 is healthy: successfully committed proposal: took = 9.918673ms https: //172 .16.60.233:2379 is healthy: successfully committed proposal: took = 10.985279ms https: //172 .16.60.232:2379 is healthy: successfully committed proposal: took = 13.422545ms   [root@k8s-master01 ~] # ETCDCTL_API=3 etcdctl --endpoints="https://172.16.60.231:2379,https://172.16.60.232:2379,https://172.16.60.233:2379" --cert=/etc/etcd/cert/etcd.pem --key=/etc/etcd/cert/etcd-key.pem --cacert=/etc/kubernetes/cert/ca.pem member list --write-out=table +------------------+---------+------------+----------------------------+----------------------------+------------+ |        ID        | STATUS  |    NAME    |         PEER ADDRS         |        CLIENT ADDRS        | IS LEARNER | +------------------+---------+------------+----------------------------+----------------------------+------------+ | 1d1d7edbba38c293 | started | k8s-etcd03 | https: //172 .16.60.233:2380 | https: //172 .16.60.233:2379 |       false  | | 4c0cfad24e92e45f | started | k8s-etcd02 | https: //172 .16.60.232:2380 | https: //172 .16.60.232:2379 |       false  | | 79cf4f0a8c3da54b | started | k8s-etcd01 | https: //172 .16.60.231:2380 | https: //172 .16.60.231:2379 |       false  | +------------------+---------+------------+----------------------------+----------------------------+------------+

　　

如上发现，etcd集群三个节点的leader都是false，即没有选主。此时需要重启三个节点的etcd服务：

1	# systemctl restart etcd

　　

重启后，再次查看发现etcd集群已经选主成功，集群状态正常！

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[root@k8s-master01 ~] # ETCDCTL_API=3 etcdctl -w table --cacert=/etc/kubernetes/cert/ca.pem   --cert=/etc/etcd/cert/etcd.pem   --key=/etc/etcd/cert/etcd-key.pem   --endpoints="https://172.16.60.231:2379,https://172.16.60.232:2379,https://172.16.60.233:2379" endpoint status +----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+ |          ENDPOINT          |        ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS | +----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+ | https: //172 .16.60.231:2379 | 79cf4f0a8c3da54b |   3.4.9 |  1.6 MB |       true  |       false  |         5 |      24658 |              24658 |        | | https: //172 .16.60.232:2379 | 4c0cfad24e92e45f |   3.4.9 |  1.6 MB |      false  |       false  |         5 |      24658 |              24658 |        | | https: //172 .16.60.233:2379 | 1d1d7edbba38c293 |   3.4.9 |  1.7 MB |      false  |       false  |         5 |      24658 |              24658 |        | +----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+

　　

但是，k8s集群数据其实已经丢失了。namespace命名空间下的pod等资源都没有了。此时就需要通过etcd集群备份文件来恢复，即通过上面的etcd集群快照文件恢复。

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[root@k8s-master01 ~] # kubectl get ns NAME              STATUS   AGE default           Active   9m47s kube-node-lease   Active   9m39s kube-public       Active   9m39s kube-system       Active   9m47s [root@k8s-master01 ~] # kubectl get pods -n kube-system No resources found  in  kube-system namespace. [root@k8s-master01 ~] # kubectl get pods --all-namespaces No resources found

　　

2）etcd集群数据恢复，即kubernetes集群数据恢复

在etcd数据恢复之前，先依次关闭所有master节点的kube-aposerver服务，所有etcd节点的etcd服务：

1 2	# systemctl stop kube-apiserver # systemctl stop etcd

　　

特别注意：在进行etcd集群数据恢复之前，一定要先将所有etcd节点的data和wal旧工作目录删掉，这里指的是/data/k8s/etcd/data文件夹跟/data/k8s/etcd/wal文件夹，可能会导致恢复失败（恢复命令执行时报错数据目录已存在）。

1	# rm -rf /data/k8s/etcd/data && rm -rf /data/k8s/etcd/wal

　　

在每个etcd节点执行恢复操作：

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172.16.60.231节点 ------------------------------------------------------- ETCDCTL_API=3 etcdctl \ --name=k8s-etcd01 \ --endpoints= "https://172.16.60.231:2379"  \ --cert= /etc/etcd/cert/etcd .pem \ --key= /etc/etcd/cert/etcd-key .pem \ --cacert= /etc/kubernetes/cert/ca .pem \ --initial-cluster-token=etcd-cluster-0 \ --initial-advertise-peer-urls=https: //172 .16.60.231:2380 \ --initial-cluster=k8s-etcd01=https: //172 .16.60.231:2380,k8s-etcd02=https: //172 .16.60.232:2380,k8s-etcd03=https: //192 .168.137.233:2380 \ --data- dir = /data/k8s/etcd/data  \ --wal- dir = /data/k8s/etcd/wal  \ snapshot restore  /data/etcd_backup_dir/etcd-snapshot-20200820 .db     172.16.60.232节点 ------------------------------------------------------- ETCDCTL_API=3 etcdctl \ --name=k8s-etcd02 \ --endpoints= "https://172.16.60.232:2379"  \ --cert= /etc/etcd/cert/etcd .pem \ --key= /etc/etcd/cert/etcd-key .pem \ --cacert= /etc/kubernetes/cert/ca .pem \ --initial-cluster-token=etcd-cluster-0 \ --initial-advertise-peer-urls=https: //172 .16.60.232:2380 \ --initial-cluster=k8s-etcd01=https: //172 .16.60.231:2380,k8s-etcd02=https: //172 .16.60.232:2380,k8s-etcd03=https: //192 .168.137.233:2380 \ --data- dir = /data/k8s/etcd/data  \ --wal- dir = /data/k8s/etcd/wal  \ snapshot restore  /data/etcd_backup_dir/etcd-snapshot-20200820 .db     192.168.137.233节点 ------------------------------------------------------- ETCDCTL_API=3 etcdctl \ --name=k8s-etcd03 \ --endpoints= "https://192.168.137.233:2379"  \ --cert= /etc/etcd/cert/etcd .pem \ --key= /etc/etcd/cert/etcd-key .pem \ --cacert= /etc/kubernetes/cert/ca .pem \ --initial-cluster-token=etcd-cluster-0 \ --initial-advertise-peer-urls=https: //192 .168.137.233:2380 \ --initial-cluster=k8s-etcd01=https: //172 .16.60.231:2380,k8s-etcd02=https: //172 .16.60.232:2380,k8s-etcd03=https: //192 .168.137.233:2380 \ --data- dir = /data/k8s/etcd/data  \ --wal- dir = /data/k8s/etcd/wal  \ snapshot restore  /data/etcd_backup_dir/etcd-snapshot-20200820 .db

　　

依次启动所有etcd节点的etcd服务：

1 2	# systemctl start etcd # systemctl status etcd

　　

检查 ETCD 集群状态（如下，发现etcd集群里已经成功选主了）

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[root@k8s-master01 ~] # ETCDCTL_API=3 etcdctl --endpoints="https://172.16.60.231:2379,https://172.16.60.232:2379,https://172.16.60.233:2379" --cert=/etc/etcd/cert/etcd.pem --key=/etc/etcd/cert/etcd-key.pem --cacert=/etc/kubernetes/cert/ca.pem endpoint health https: //172 .16.60.232:2379 is healthy: successfully committed proposal: took = 12.837393ms https: //172 .16.60.233:2379 is healthy: successfully committed proposal: took = 13.306671ms https: //172 .16.60.231:2379 is healthy: successfully committed proposal: took = 13.602805ms   [root@k8s-master01 ~] # ETCDCTL_API=3 etcdctl -w table --cacert=/etc/kubernetes/cert/ca.pem   --cert=/etc/etcd/cert/etcd.pem   --key=/etc/etcd/cert/etcd-key.pem   --endpoints="https://172.16.60.231:2379,https://172.16.60.232:2379,https://172.16.60.233:2379" endpoint status +----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+ |          ENDPOINT          |        ID        | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS | +----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+ | https: //172 .16.60.231:2379 | 79cf4f0a8c3da54b |   3.4.9 |  9.0 MB |      false  |       false  |         2 |         13 |                 13 |        | | https: //172 .16.60.232:2379 | 4c0cfad24e92e45f |   3.4.9 |  9.0 MB |       true  |       false  |         2 |         13 |                 13 |        | | https: //172 .16.60.233:2379 | 5f70664d346a6ebd |   3.4.9 |  9.0 MB |      false  |       false  |         2 |         13 |                 13 |        | +----------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+

　　

再依次启动所有master节点的kube-apiserver服务：

1 2	# systemctl start kube-apiserver # systemctl status kube-apiserver

　　

查看kubernetes集群状态：

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[root@k8s-master01 ~] # kubectl get cs NAME                 STATUS      MESSAGE                                  ERROR controller-manager   Healthy     ok scheduler            Healthy     ok etcd-2               Unhealthy   HTTP probe failed with statuscode: 503 etcd-1               Unhealthy   HTTP probe failed with statuscode: 503 etcd-0               Unhealthy   HTTP probe failed with statuscode: 503   由于etcd服务刚重启，需要多刷几次状态就会正常： [root@k8s-master01 ~] # kubectl get cs NAME                 STATUS    MESSAGE             ERROR controller-manager   Healthy   ok scheduler            Healthy   ok etcd-2               Healthy   { "health" : "true" } etcd-0               Healthy   { "health" : "true" } etcd-1               Healthy   { "health" : "true" }

　　

查看kubernetes的资源情况：

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[root@k8s-master01 ~] # kubectl get ns NAME              STATUS   AGE default           Active   7d4h kevin             Active   5d18h kube-node-lease   Active   7d4h kube-public       Active   7d4h kube-system       Active   7d4h   [root@k8s-master01 ~] # kubectl get pods --all-namespaces NAMESPACE     NAME                                       READY   STATUS              RESTARTS   AGE default       dnsutils-ds-22q87                          0 /1      ContainerCreating   171        7d3h default       dnsutils-ds-bp8tm                          0 /1      ContainerCreating   138        5d18h default       dnsutils-ds-bzzqg                          0 /1      ContainerCreating   138        5d18h default       dnsutils-ds-jcvng                          1 /1      Running             171        7d3h default       dnsutils-ds-xrl2x                          0 /1      ContainerCreating   138        5d18h default       dnsutils-ds-zjg5l                          1 /1      Running             0          7d3h default       kevin-t-84cdd49d65-ck47f                   0 /1      ContainerCreating   0          2d2h default       nginx-ds-98rm2                             1 /1      Running             2          7d3h default       nginx-ds-bbx68                             1 /1      Running             0          7d3h default       nginx-ds-kfctv                             0 /1      ContainerCreating   1          5d18h default       nginx-ds-mdcd9                             0 /1      ContainerCreating   1          5d18h default       nginx-ds-ngqcm                             1 /1      Running             0          7d3h default       nginx-ds-tpcxs                             0 /1      ContainerCreating   1          5d18h kevin         nginx-ingress-controller-797ffb479-vrq6w   0 /1      ContainerCreating   0          5d18h kevin          test -nginx-7d4f96b486-qd4fl                0 /1      ContainerCreating   0          2d1h kevin          test -nginx-7d4f96b486-qfddd                0 /1      Running             0          2d1h kube-system   calico-kube-controllers-578894d4cd-9rp4c   1 /1      Running             1          7d3h kube-system   calico-node-d7wq8                          0 /1      PodInitializing     1          7d3h

在etcd集群数据恢复后，pod容器也会慢慢恢复到running状态。至此，kubernetes整个集群已经通过etcd备份数据恢复了。

 

三、最后总结

Kubernetes 集群备份主要是备份 ETCD 集群。而恢复时，主要考虑恢复整个顺序：

停止kube-apiserver --> 停止ETCD --> 恢复数据 --> 启动ETCD --> 启动kube-apiserve

 

特别注意：

• 备份ETCD集群时，只需要备份一个ETCD数据，然后同步到其他节点上。
• 恢复ETCD数据时，拿其中一个节点的备份数据恢复即可

转自

K8S集群灾备环境部署 - 散尽浮华 - 博客园
https://www.cnblogs.com/kevingrace/p/14616824.html