k8s 集群中的etcd故障解决

一次在k8s集群中创建实例发现etcd集群状态出现连接失败状况,导致创建实例失败。于是排查了一下原因。

问题来源

下面是etcd集群健康状态:

[root@docker01 ~]# cd /opt/kubernetes/ssl/
[root@docker01 ssl]# /opt/kubernetes/bin/etcdctl \
> --ca-file=ca.pem --cert-file=server.pem --key-file=server-key.pem \
> --endpoints="https://10.0.0.99:2379,https://10.0.0.100:2379,https://10.0.0.111:2379" \
> cluster-health
member 1bd4d12de986e887 is healthy: got healthy result from https://10.0.0.99:2379
member 45396926a395958b is healthy: got healthy result from https://10.0.0.100:2379
failed to check the health of member c2c5804bd87e2884 on https://10.0.0.111:2379: Get https://10.0.0.111:2379/health: net/http: TLS handshake timeout
member c2c5804bd87e2884 is unreachable: [https://10.0.0.111:2379] are all unreachable
cluster is healthy
[root@docker01 ssl]# 

可以明显看到etcd节点03出现问题。

这个时候到节点03上来重启etcd服务如下:

[root@docker03 ~]# systemctl restart etcd
Job for etcd.service failed because the control process exited with error code. See "systemctl status etcd.service" and "journalctl -xe" for details.
[root@docker03 ~]# journalctl -xe
Mar 24 22:24:32 docker03 etcd[1895]: setting maximum number of CPUs to 1, total number of available CPUs is 1
Mar 24 22:24:32 docker03 etcd[1895]: the server is already initialized as member before, starting as etcd member...
Mar 24 22:24:32 docker03 etcd[1895]: peerTLS: cert = /opt/kubernetes/ssl/server.pem, key = /opt/kubernetes/ssl/server-key.pem, ca = , trusted-ca = /opt/kubernetes/ssl
Mar 24 22:24:32 docker03 etcd[1895]: listening for peers on https://10.0.0.111:2380
Mar 24 22:24:32 docker03 etcd[1895]: The scheme of client url http://127.0.0.1:2379 is HTTP while peer key/cert files are presented. Ignored key/cert files.
Mar 24 22:24:32 docker03 etcd[1895]: listening for client requests on 127.0.0.1:2379
Mar 24 22:24:32 docker03 etcd[1895]: listening for client requests on 10.0.0.111:2379
Mar 24 22:24:32 docker03 etcd[1895]: member c2c5804bd87e2884 has already been bootstrapped
Mar 24 22:24:32 docker03 systemd[1]: etcd.service: main process exited, code=exited, status=1/FAILURE
Mar 24 22:24:32 docker03 systemd[1]: Failed to start Etcd Server.
-- Subject: Unit etcd.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit etcd.service has failed.
-- 
-- The result is failed.
Mar 24 22:24:32 docker03 systemd[1]: Unit etcd.service entered failed state.
Mar 24 22:24:32 docker03 systemd[1]: etcd.service failed.
Mar 24 22:24:33 docker03 systemd[1]: etcd.service holdoff time over, scheduling restart.
Mar 24 22:24:33 docker03 systemd[1]: start request repeated too quickly for etcd.service
Mar 24 22:24:33 docker03 systemd[1]: Failed to start Etcd Server.
-- Subject: Unit etcd.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit etcd.service has failed.
-- 
-- The result is failed.
Mar 24 22:24:33 docker03 systemd[1]: Unit etcd.service entered failed state.
Mar 24 22:24:33 docker03 systemd[1]: etcd.service failed.

并没有成功启动服务,可以看到提示信息:member c2c5804bd87e2884 has already been bootstrapped

查看资料说是:
One of the member was bootstrapped via discovery service. You must remove the previous data-dir to clean up the member information. Or the member will ignore the new configuration and start with the old configuration. That is why you see the mismatch.
大概意思:
其中一个成员是通过discovery service引导的。必须删除以前的数据目录来清理成员信息。否则成员将忽略新配置,使用旧配置。这就是为什么你看到了不匹配。
看到了这里,问题所在也就很明确了,启动失败的原因在于data-dir (/var/lib/etcd/default.etcd)中记录的信息与 etcd启动的选项所标识的信息不太匹配造成的。

问题解决

第一种方式我们可以通过修改启动参数解决这类错误。既然 data-dir 中已经记录信息,我们就没必要在启动项中加入多于配置。具体修改--initial-cluster-state参数:

[root@docker03 ~]# cat /usr/lib/systemd/system/etcd.service
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target

[Service]
Type=notify
EnvironmentFile=-/opt/kubernetes/cfg/etcd
ExecStart=/opt/kubernetes/bin/etcd \
--name=${ETCD_NAME} \
--data-dir=${ETCD_DATA_DIR} \
--listen-peer-urls=${ETCD_LISTEN_PEER_URLS} \
--listen-client-urls=${ETCD_LISTEN_CLIENT_URLS},http://127.0.0.1:2379 \
--advertise-client-urls=${ETCD_ADVERTISE_CLIENT_URLS} \
--initial-advertise-peer-urls=${ETCD_INITIAL_ADVERTISE_PEER_URLS} \
--initial-cluster=${ETCD_INITIAL_CLUSTER} \
--initial-cluster-token=${ETCD_INITIAL_CLUSTER} \
--initial-cluster-state=existing \  # 将new这个参数修改成existing,启动正常!
--cert-file=/opt/kubernetes/ssl/server.pem \
--key-file=/opt/kubernetes/ssl/server-key.pem \
--peer-cert-file=/opt/kubernetes/ssl/server.pem \
--peer-key-file=/opt/kubernetes/ssl/server-key.pem \
--trusted-ca-file=/opt/kubernetes/ssl/ca.pem \
--peer-trusted-ca-file=/opt/kubernetes/ssl/ca.pem
Restart=on-failure
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

我们将 --initial-cluster-state=new 修改成  --initial-cluster-state=existing,再次重新启动就ok了。

第二种方式删除所有etcd节点的 data-dir 文件(不删也行),重启各个节点的etcd服务,这个时候,每个节点的data-dir的数据都会被更新,就不会有以上故障了。

第三种方式是复制其他节点的data-dir中的内容,以此为基础上以 --force-new-cluster 的形式强行拉起一个,然后以添加新成员的方式恢复这个集群。

这是目前的几种解决办法

posted @ 2019-03-26 15:43  ThreeCode  阅读(21126)  评论(0编辑  收藏