k8s集群备份与恢复

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介绍

k8s集群的备份与恢复，主要就是etcd集群的备份与恢复。

ETCD一些基础查询操作

查看集群状态

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二进制：
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://10.16.2.17:2379,https://10.16.2.18:2379,https://10.16.2.19:2379 endpoint health


阿里kubeadm：
ETCDCTL_API=3 etcdctl --cacert=/etc/kubernetes/pki/etcd/ca.pem --cert=/etc/kubernetes/pki/etcd/etcd-client.pem --key=/etc/kubernetes/pki/etcd/etcd-client-key.pem --endpoints=https://192.168.34.130:2379,https://192.168.34.131:2379,https://192.168.34.132:2379,https://192.168.34.133:2379,https://192.168.34.134:2379 endpoint health

获取某个key信息

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二进制：
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://10.16.2.17:2379,https://10.16.2.18:2379,https://10.16.2.19:2379 get /registry/apiregistration.k8s.io/apiservices/v1.apps

阿里kubeadm：
ETCDCTL_API=3 etcdctl --cacert=/etc/kubernetes/pki/etcd/ca.pem --cert=/etc/kubernetes/pki/etcd/etcd-client.pem --key=/etc/kubernetes/pki/etcd/etcd-client-key.pem --endpoints=https://192.168.34.130:2379,https://192.168.34.131:2379,https://192.168.34.132:2379,https://192.168.34.133:2379,https://192.168.34.134:2379 get /registry/apiregistration.k8s.io/apiservices/v1.apps

获取etcd版本信息

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二进制：
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://10.16.2.17:2379,https://10.16.2.18:2379,https://10.16.2.19:2379 version

阿里kubeadm：
ETCDCTL_API=3 etcdctl --cacert=/etc/kubernetes/pki/etcd/ca.pem --cert=/etc/kubernetes/pki/etcd/etcd-client.pem --key=/etc/kubernetes/pki/etcd/etcd-client-key.pem --endpoints=https://192.168.34.130:2379,https://192.168.34.131:2379,https://192.168.34.132:2379,https://192.168.34.133:2379,https://192.168.34.134:2379  version

获取etcd所有key

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二进制：
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://10.16.2.17:2379,https://10.16.2.18:2379,https://10.16.2.19:2379 get / --prefix --keys-only

阿里kubeadm：
ETCDCTL_API=3 etcdctl --cacert=/etc/kubernetes/pki/etcd/ca.pem --cert=/etc/kubernetes/pki/etcd/etcd-client.pem --key=/etc/kubernetes/pki/etcd/etcd-client-key.pem --endpoints=https://192.168.34.130:2379,https://192.168.34.131:2379,https://192.168.34.132:2379,https://192.168.34.133:2379,https://192.168.34.134:2379  get / --prefix --keys-only

备份

本文备份使用 napshot save , 每次备份一个节点就行。 

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二进制举例
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://10.16.2.17:2379  snapshot save /data/etcd_backup_dir/etcd-snapshot-`date +%Y%m%d`.db

恢复

停止kube-apiserver 服务，确保apiserver 服务已经停止运行 

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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 

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systemctl stop etcd

移除 ETCD 数据 

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mv /data/k8s/etcd/data /data/k8s/etcd/data.bak   
mv /data/k8s/etcd/wal  /data/k8s/etcd/wal.bak

拷贝 ETCD 备份快照 

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scp /var/lib/etcd_backup/etcd-snapshot-20200414.db root@master2:/data/etcd_backup_dir/
scp /var/lib/etcd_backup/etcd-snapshot-20200414.db root@master3:/data/etcd_backup_dir/

所有master上按照各自etcd的启动文件，恢复。

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ETCDCTL_API=3 etcdctl snapshot restore /data/etcd_backup_dir/etcd-snapshot-20200414.db \
  --name bjxg-sy-test \
  --initial-cluster "bjxg-sy-test=https://10.16.2.17:2380" \
  --initial-cluster-token etcd-cluster-0 \
  --initial-advertise-peer-urls https://10.16.2.17:2380 \
  --data-dir=/data/k8s/etcd/data --wal-dir=/data/k8s/etcd/wal

查恢复的name，cluster-token等 

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[root@etcd_backup_dir]# systemctl status etcd
● etcd.service - Etcd Server
   Loaded: loaded (/etc/systemd/system/etcd.service; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2020-04-14 11:44:42 CST; 2h 38min ago
     Docs: https://github.com/coreos
 Main PID: 25729 (etcd)
    Tasks: 15
   Memory: 55.6M
   CGroup: /system.slice/etcd.service
           └─25729 /opt/k8s/bin/etcd --data-dir=/data/k8s/etcd/data --wal-dir=/data/k8s/etcd/wal ........
           
           
从 /etc/systemd/system/etcd.service文件里面读取信息

启动etcd，kube-apiserver 

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systemctl start etcd
systemctl start kube-apiserver

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： 

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

参考链接

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https://www.jianshu.com/p/8b483ed49f26
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