K8S集群灾备环境部署
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
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
# 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:
[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
[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:
[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:
[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)
# rm -rf /data/k8s/etcd/data/*
查看k8s集群状态:
[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:
[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:
# 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!
[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。
[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:
# 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)。
# rm -rf /data/k8s/etcd/data && rm -rf /data/k8s/etcd/wal
在每个etcd节点执行恢复操作:
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:
# 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)
[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:
# systemctl start kube-apiserver # systemctl status kube-apiserver
查看kubernetes集群状态:
[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:
[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。
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