ETCD 简介
ETCD
是用于共享配置和服务发现的分布式,一致性的KV存储系统。ETCD是CoreOS公司发起的一个开源项目,授权协议为Apache。
ETCD 使用场景
ETCD 有很多使用场景,包括但不限于:
- 配置管理
- 服务注册于发现
- 选主
- 应用调度
- 分布式队列
- 分布式锁
ETCD 存储 k8s 所有数据信息
ETCD 是k8s集群极为重要的一块服务,存储了集群所有的数据信息。同理,如果发生灾难或者 etcd 的数据丢失,都会影响集群数据的恢复。所以,本文重点讲如何备份和恢复数据。
ETCD 一些查询操作
- 查看集群状态
$ ETCDCTL_API=3 etcdctl --cacert=/opt/kubernetes/ssl/ca.pem --cert=/opt/kubernetes/ssl/server.pem --key=/opt/kubernetes/ssl/server-key.pem --endpoints=https://192.168.1.36:2379,https://192.168.1.37:2379,https://192.168.1.38:2379 endpoint health
https://192.168.1.36:2379 is healthy: successfully committed proposal: took = 1.698385ms
https://192.168.1.37:2379 is healthy: successfully committed proposal: took = 1.577913ms
https://192.168.1.38:2379 is healthy: successfully committed proposal: took = 5.616079ms
- 获取某个 key 信息
$ ETCDCTL_API=3 etcdctl --cacert=/opt/kubernetes/ssl/ca.pem --cert=/opt/kubernetes/ssl/server.pem --key=/opt/kubernetes/ssl/server-key.pem --endpoints=https://192.168.1.36:2379,https://192.168.1.37:2379,https://192.168.1.38:2379 get /registry/apiregistration.k8s.io/apiservices/v1.apps
- 获取 etcd 版本信息
$ ETCDCTL_API=3 etcdctl --cacert=/opt/kubernetes/ssl/ca.pem --cert=/opt/kubernetes/ssl/server.pem --key=/opt/kubernetes/ssl/server-key.pem --endpoints=https://192.168.1.36:2379,https://192.168.1.37:2379,https://192.168.1.38:2379 version
- 获取 ETCD 所有的 key
$ ETCDCTL_API=3 etcdctl --cacert=/opt/kubernetes/ssl/ca.pem --cert=/opt/kubernetes/ssl/server.pem --key=/opt/kubernetes/ssl/server-key.pem --endpoints=https://192.168.1.36:2379,https://192.168.1.37:2379,https://192.168.1.38:2379 get / --prefix --keys-only
环境
主机 | IP |
k8s-master1 | 192.168.1.36 |
k8s-master2 | 192.168.1.37 |
k8s-master3 | 192.168.1.38 |
- ETCD version 3.2.12
- Kubernetes version v1.15.6 二进制安装
备份
注意
:ETCD 不同的版本的 etcdctl 命令不一样,但大致差不多,本文备份使用 napshot save
, 每次备份一个节点
就行。
命令备份
(k8s-master1 机器上备份):
$ ETCDCTL_API=3 etcdctl --cacert=/opt/kubernetes/ssl/ca.pem --cert=/opt/kubernetes/ssl/server.pem --key=/opt/kubernetes/ssl/server-key.pem --endpoints=https://192.168.1.36:2379 snapshot save /data/etcd_backup_dir/etcd-snapshot-`date +%Y%m%d`.db
备份脚本
(k8s-master1 机器上备份):
#!/usr/bin/env bash
date;
CACERT="/opt/kubernetes/ssl/ca.pem"
CERT="/opt/kubernetes/ssl/server.pem"
EKY="/opt/kubernetes/ssl/server-key.pem"
ENDPOINTS="192.168.1.36:2379"
ETCDCTL_API=3 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 {} \;
恢复
准备工作
- 停止所有 Master 上
kube-apiserver
服务
$ systemctl stop kube-apiserver
# 确认 kube-apiserver 服务是否停止
$ ps -ef | grep kube-apiserver
- 停止集群中所有 ETCD 服务
$ systemctl stop etcd
- 移除所有 ETCD 存储目录下数据
$ mv /var/lib/etcd/default.etcd /var/lib/etcd/default.etcd.bak
- 拷贝 ETCD 备份快照
# 从 k8s-master1 机器上拷贝备份
$ scp /data/etcd_backup_dir/etcd-snapshot-20191222.db root@k8s-master2:/data/etcd_backup_dir/
$ scp /data/etcd_backup_dir/etcd-snapshot-20191222.db root@k8s-master3:/data/etcd_backup_dir/
恢复备份
# k8s-master1 机器上操作
$ ETCDCTL_API=3 etcdctl snapshot restore /data/etcd_backup_dir/etcd-snapshot-20191222.db \
--name etcd-0 \
--initial-cluster "etcd-0=https://192.168.1.36:2380,etcd-1=https://192.168.1.37:2380,etcd-2=https://192.168.1.38:2380" \
--initial-cluster-token etcd-cluster \
--initial-advertise-peer-urls https://192.168.1.36:2380 \
--data-dir=/var/lib/etcd/default.etcd
# k8s-master2 机器上操作
$ ETCDCTL_API=3 etcdctl snapshot restore /data/etcd_backup_dir/etcd-snapshot-20191222.db \
--name etcd-1 \
--initial-cluster "etcd-0=https://192.168.1.36:2380,etcd-1=https://192.168.1.37:2380,etcd-2=https://192.168.1.38:2380" \
--initial-cluster-token etcd-cluster \
--initial-advertise-peer-urls https://192.168.1.37:2380 \
--data-dir=/var/lib/etcd/default.etcd
# k8s-master3 机器上操作
$ ETCDCTL_API=3 etcdctl snapshot restore /data/etcd_backup_dir/etcd-snapshot-20191222.db \
--name etcd-2 \
--initial-cluster "etcd-0=https://192.168.1.36:2380,etcd-1=https://192.168.1.37:2380,etcd-2=https://192.168.1.38:2380" \
--initial-cluster-token etcd-cluster \
--initial-advertise-peer-urls https://192.168.1.38:2380 \
--data-dir=/var/lib/etcd/default.etcd
上面三台 ETCD 都恢复完成后,依次登陆三台机器启动 ETCD
$ systemctl start etcd
三台 ETCD 启动完成,检查 ETCD 集群状态
$ ETCDCTL_API=3 etcdctl --cacert=/opt/kubernetes/ssl/ca.pem --cert=/opt/kubernetes/ssl/server.pem --key=/opt/kubernetes/ssl/server-key.pem --endpoints=https://192.168.1.36:2379,https://192.168.1.37:2379,https://192.168.1.38:2379 endpoint health
三台 ETCD 全部健康,分别到每台 Master 启动 kube-apiserver
$ systemctl start kube-apiserver
检查 Kubernetes 集群是否恢复正常
$ kubectl get cs
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
注意
:备份ETCD集群时,只需要备份一个ETCD就行,恢复时,拿同一份备份数据恢复。
参考链接