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k8s初级实战10--备份etcd集群
- 1 基础概念
- 2 常见用法
- 2.1 备份etcd
- 2.2 还原etcd
- 3 注意事项
- 4 说明
1 基础概念
Etcd 是 CoreOS 基于 Raft 开发的分布式 key-value 存储，可用于服务发现、共享配置以及一致性保障（如数据库选主、分布式锁等）。Etcd 是兼具一致性和高可用性的键值数据库，可以作为保存 Kubernetes 所有集群数据的后台数据库。
2 常见用法
2.1 备份etcd
- 拷贝etcdctl 到 /usr/bin
# docker cp k8s_etcd_etcd-kmaster_kube-system_8d474956e7bbb5b3129a652bc831f31f_3:/usr/local/bin/etcdctl /usr/bin # etcdctl version etcdctl version: 3.4.13 API version: 3.4 - 创建目录并备份etcd
# mkdir /etcd_backup/ # ETCDCTL_API=3 etcdctl --endpoints https://192.168.2.131:2379 \ --cacert=/etc/kubernetes/pki/etcd/ca.crt \ --cert=/etc/kubernetes/pki/etcd/peer.crt \ --key=/etc/kubernetes/pki/etcd/peer.key \ snapshot save /etcd_backup/snapshot.db 输出： {"level":"info","ts":1610252289.038325,"caller":"snapshot/v3_snapshot.go:119","msg":"created temporary db file","path":"/etcd_backup/snapshot.db.part"} {"level":"info","ts":"2021-01-10T04:18:09.045Z","caller":"clientv3/maintenance.go:200","msg":"opened snapshot stream; downloading"} {"level":"info","ts":1610252289.045765,"caller":"snapshot/v3_snapshot.go:127","msg":"fetching snapshot","endpoint":"https://192.168.2.131:2379"} {"level":"info","ts":"2021-01-10T04:18:09.107Z","caller":"clientv3/maintenance.go:208","msg":"completed snapshot read; closing"} {"level":"info","ts":1610252289.131032,"caller":"snapshot/v3_snapshot.go:142","msg":"fetched snapshot","endpoint":"https://192.168.2.131:2379","size":"4.9 MB","took":0.092062186} {"level":"info","ts":1610252289.131579,"caller":"snapshot/v3_snapshot.go:152","msg":"saved","path":"/etcd_backup/snapshot.db"} Snapshot saved at /etcd_backup/snapshot.db查看备份状态： # ETCDCTL_API=3 etcdctl --endpoints https://192.168.2.131:2379 \ --cacert=/etc/kubernetes/pki/etcd/ca.crt \ --cert=/etc/kubernetes/pki/etcd/peer.crt \ --key=/etc/kubernetes/pki/etcd/peer.key \ --write-out=table snapshot status /etcd_backup/snapshot.db 输出： +---------+----------+------------+------------+ | HASH | REVISION | TOTAL KEYS | TOTAL SIZE | +---------+----------+------------+------------+ | 5e57128 | 34397 | 1724 | 4.9 MB | +---------+----------+------------+------------+ - 定时备份
编写执行脚本 cat << EOF > etcd_backup.sh #!/bin/bash IP=192.168.2.131 BACKUP=/etcd_backup/ export ETCDCTL_API=3 mkdir -p $BACKUP etcdctl --endpoints=https://$IP:2379 \ --cacert=/etc/kubernetes/pki/etcd/ca.crt \ --cert=/etc/kubernetes/pki/etcd/peer.crt \ --key=/etc/kubernetes/pki/etcd/peer.key \ snapshot save $BACKUP/snap-$(date +%Y%m%d%H%M).db EOF编写定时任务 crontab -e 0 0 * * * /bin/sh /root/etcd_backup.sh
2.2 还原etcd
- 查看etcd是否健康
# ETCDCTL_API=3 etcdctl \ --endpoints https://192.168.2.131:2379 \ --cacert=/etc/kubernetes/pki/etcd/ca.crt \ --cert=/etc/kubernetes/pki/etcd/peer.crt \ --key=/etc/kubernetes/pki/etcd/peer.key endpoint health 输出： https://192.168.2.131:2379 is healthy: successfully committed proposal: took = 8.306439ms - 查看etcd的成员列表
# ETCDCTL_API=3 etcdctl \ --endpoints https://192.168.2.131:2379 \ --cacert=/etc/kubernetes/pki/etcd/ca.crt \ --cert=/etc/kubernetes/pki/etcd/peer.crt \ --key=/etc/kubernetes/pki/etcd/peer.key member list 输出： 9cb4eb07d38510b5, started, kmaster, https://192.168.2.131:2380, https://192.168.2.131:2379, false - 查看 etcd pod 的yaml配置
# kubectl -n kube-system get pod etcd-kmaster -o yaml - 删除 etcd 的数据目录
# mv /var/lib/etcd/ /var/lib/etcd-bak 再次查看健康状态，提示unhealthy {"level":"warn","ts":"2021-01-10T05:00:38.988Z","caller":"clientv3/retry_interceptor.go:62","msg":"retrying of unary invoker failed","target":"endpoint://client-a1e6e93c-6091-447b-ae77-2ed622d92ab2/192.168.2.131:2379","attempt":0,"error":"rpc error: code = DeadlineExceeded desc = latest balancer error: all SubConns are in TransientFailure, latest connection error: connection error: desc = \"transport: Error while dialing dial tcp 192.168.2.131:2379: connect: connection refused\""} https://192.168.2.131:2379 is unhealthy: failed to commit proposal: context deadline exceeded Error: unhealthy cluster - 还原 etcd
# ETCDCTL_API=3 etcdctl snapshot restore /etcd_backup/snapshot.db \ --cacert=/etc/kubernetes/pki/etcd/ca.crt \ --cert=/etc/kubernetes/pki/etcd/peer.crt \ --key=/etc/kubernetes/pki/etcd/peer.key \ --name=kmaster \ --data-dir=/var/lib/etcd \ --skip-hash-check \ --initial-advertise-peer-urls=https://192.168.2.131:2380 \ --initial-cluster=kmaster=https://192.168.2.131:2380 输出： {"level":"info","ts":1610254983.838928,"caller":"snapshot/v3_snapshot.go:296","msg":"restoring snapshot","path":"/etcd_backup/snapshot.db","wal-dir":"/var/lib/etcd/member/wal","data-dir":"/var/lib/etcd","snap-dir":"/var/lib/etcd/member/snap"} {"level":"info","ts":1610254983.8676407,"caller":"mvcc/kvstore.go:380","msg":"restored last compact revision","meta-bucket-name":"meta","meta-bucket-name-key":"finishedCompactRev","restored-compact-revision":33324} {"level":"info","ts":1610254983.880514,"caller":"membership/cluster.go:392","msg":"added member","cluster-id":"65567032c1db9f01","local-member-id":"0","added-peer-id":"9cb4eb07d38510b5","added-peer-peer-urls":["https://192.168.2.131:2380"]} {"level":"info","ts":1610254983.9191227,"caller":"snapshot/v3_snapshot.go:309","msg":"restored snapshot","path":"/etcd_backup/snapshot.db","wal-dir":"/var/lib/etcd/member/wal","data-dir":"/var/lib/etcd","snap-dir":"/var/lib/etcd/member/snap"} 确认已经恢复： # ls /var/lib/etcd member # 查看健康状态 https://192.168.2.131:2379 is healthy: successfully committed proposal: took = 7.854868ms
3 注意事项
- 在实际使用中，如果忘记了etcdctl的使用命令，可以通过-h 面临来查看命令所需的参数
# kubectl -n kube-system exec -it etcd-MasterNodeName -- etcdctl -h
4 说明
任务->管理集群->为 Kubernetes 运行 etcd 集群
feiskyer/kubernetes-handbook/blob/master/components/etcd
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