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版本:v2.8

etcd 节点故障排除

本文介绍了对具有 etcd 角色的节点进行故障排除的命令和提示。

检查 etcd 容器是否正在运行

etcd 容器的状态应该是 UpUp 后面显示的时间指的是容器运行的时间。

docker ps -a -f=name=etcd$

输出示例:

CONTAINER ID   IMAGE                                 COMMAND                  CREATED          STATUS          PORTS     NAMES
d26adbd23643 rancher/mirrored-coreos-etcd:v3.5.7 "/usr/local/bin/etcd…" 30 minutes ago Up 30 minutes etcd

etcd 容器日志记录

容器的日志记录可能包含问题的信息。

docker logs etcd
日志解释
health check for peer xxx could not connect: dial tcp IP:2380: getsockopt: connection refused无法连接到端口 2380 上显示的地址。检查 etcd 容器是否在显示地址的主机上运行。
xxx is starting a new election at term xetcd 集群失去了集群仲裁数量,并正在尝试建立一个新的 leader。运行 etcd 的大多数节点关闭/无法访问时,可能会发生这种情况。
connection error: desc = "transport: Error while dialing dial tcp 0.0.0.0:2379: i/o timeout"; Reconnecting to {0.0.0.0:2379 0 <nil>}主机防火墙正在阻止网络通信。
rafthttp: request cluster ID mismatch具有 etcd 实例日志 rafthttp: request cluster ID mismatch 的节点正在尝试加入已经添加另一个对等节点(peer)的集群。你需要从集群中删除该节点,然后再重新添加。
rafthttp: failed to find member集群状态(/var/lib/etcd)包含加入集群的错误信息。你需要从集群中删除该节点,清理状态目录,然后再重新添加。

etcd 集群和连接检查

运行 etcd 的主机的地址配置决定了 etcd 监听的地址。如果为运行 etcd 的主机配置了内部地址,则需要显式指定 etcdctl 的端点。如果任何命令的响应是 Error: context deadline exceeded,则 etcd 实例不健康(仲裁丢失或实例未正确加入集群)。

检查所有节点上的 etcd 成员

输出应包含具有 etcd 角色的所有节点,而且所有节点上的输出应该是相同的。

命令:

docker exec etcd etcdctl member list

输出示例:

xxx, started, etcd-xxx, https://IP:2380, https://IP:2379,https://IP:4001
xxx, started, etcd-xxx, https://IP:2380, https://IP:2379,https://IP:4001
xxx, started, etcd-xxx, https://IP:2380, https://IP:2379,https://IP:4001

检查端点状态

RAFT TERM 的值应该是相等的,而且 RAFT INDEX 相差不能太大。

命令:

docker exec -e ETCDCTL_ENDPOINTS=$(docker exec etcd etcdctl member list | cut -d, -f5 | sed -e 's/ //g' | paste -sd ',') etcd etcdctl endpoint status --write-out table

输出示例:

+-----------------+------------------+---------+---------+-----------+-----------+------------+
| ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+-----------------+------------------+---------+---------+-----------+-----------+------------+
| https://IP:2379 | 333ef673fc4add56 | 3.5.7 | 24 MB | false | 72 | 66887 |
| https://IP:2379 | 5feed52d940ce4cf | 3.5.7 | 24 MB | true | 72 | 66887 |
| https://IP:2379 | db6b3bdb559a848d | 3.5.7 | 25 MB | false | 72 | 66887 |
+-----------------+------------------+---------+---------+-----------+-----------+------------+

检查端点健康

命令:

docker exec -e ETCDCTL_ENDPOINTS=$(docker exec etcd etcdctl member list | cut -d, -f5 | sed -e 's/ //g' | paste -sd ',') etcd etcdctl endpoint health

输出示例:

https://IP:2379 is healthy: successfully committed proposal: took = 2.113189ms
https://IP:2379 is healthy: successfully committed proposal: took = 2.649963ms
https://IP:2379 is healthy: successfully committed proposal: took = 2.451201ms

检查端口 TCP/2379 上的连接

命令:

for endpoint in $(docker exec etcd etcdctl member list | cut -d, -f5); do
echo "Validating connection to ${endpoint}/health"
docker run --net=host -v $(docker inspect kubelet --format '{{ range .Mounts }}{{ if eq .Destination "/etc/kubernetes" }}{{ .Source }}{{ end }}{{ end }}')/ssl:/etc/kubernetes/ssl:ro appropriate/curl -s -w "\n" --cacert $(docker inspect -f '{{range $index, $value := .Config.Env}}{{if eq (index (split $value "=") 0) "ETCDCTL_CACERT" }}{{range $i, $part := (split $value "=")}}{{if gt $i 1}}{{print "="}}{{end}}{{if gt $i 0}}{{print $part}}{{end}}{{end}}{{end}}{{end}}' etcd) --cert $(docker inspect -f '{{range $index, $value := .Config.Env}}{{if eq (index (split $value "=") 0) "ETCDCTL_CERT" }}{{range $i, $part := (split $value "=")}}{{if gt $i 1}}{{print "="}}{{end}}{{if gt $i 0}}{{print $part}}{{end}}{{end}}{{end}}{{end}}' etcd) --key $(docker inspect -f '{{range $index, $value := .Config.Env}}{{if eq (index (split $value "=") 0) "ETCDCTL_KEY" }}{{range $i, $part := (split $value "=")}}{{if gt $i 1}}{{print "="}}{{end}}{{if gt $i 0}}{{print $part}}{{end}}{{end}}{{end}}{{end}}' etcd) "${endpoint}/health"
done

输出示例:

Validating connection to https://IP:2379/health
{"health": "true"}
Validating connection to https://IP:2379/health
{"health": "true"}
Validating connection to https://IP:2379/health
{"health": "true"}

检查端口 TCP/2380 上的连接

命令:

for endpoint in $(docker exec etcd etcdctl member list | cut -d, -f4); do
echo "Validating connection to ${endpoint}/version";
docker run --net=host -v $(docker inspect kubelet --format '{{ range .Mounts }}{{ if eq .Destination "/etc/kubernetes" }}{{ .Source }}{{ end }}{{ end }}')/ssl:/etc/kubernetes/ssl:ro appropriate/curl --http1.1 -s -w "\n" --cacert $(docker inspect -f '{{range $index, $value := .Config.Env}}{{if eq (index (split $value "=") 0) "ETCDCTL_CACERT" }}{{range $i, $part := (split $value "=")}}{{if gt $i 1}}{{print "="}}{{end}}{{if gt $i 0}}{{print $part}}{{end}}{{end}}{{end}}{{end}}' etcd) --cert $(docker inspect -f '{{range $index, $value := .Config.Env}}{{if eq (index (split $value "=") 0) "ETCDCTL_CERT" }}{{range $i, $part := (split $value "=")}}{{if gt $i 1}}{{print "="}}{{end}}{{if gt $i 0}}{{print $part}}{{end}}{{end}}{{end}}{{end}}' etcd) --key $(docker inspect -f '{{range $index, $value := .Config.Env}}{{if eq (index (split $value "=") 0) "ETCDCTL_KEY" }}{{range $i, $part := (split $value "=")}}{{if gt $i 1}}{{print "="}}{{end}}{{if gt $i 0}}{{print $part}}{{end}}{{end}}{{end}}{{end}}' etcd) "${endpoint}/version"
done

输出示例:

Validating connection to https://IP:2380/version
{"etcdserver":"3.5.7","etcdcluster":"3.5.0"}
Validating connection to https://IP:2380/version
{"etcdserver":"3.5.7","etcdcluster":"3.5.0"}
Validating connection to https://IP:2380/version
{"etcdserver":"3.5.7","etcdcluster":"3.5.0"}

etcd 告警

etcd 会触发告警(例如空间不足时)。

命令:

docker exec etcd etcdctl alarm list

触发 NOSPACE 告警的输出示例:

memberID:x alarm:NOSPACE
memberID:x alarm:NOSPACE
memberID:x alarm:NOSPACE

etcd 空间错误

相关的错误消息是 etcdserver: mvcc: database space exceededapplying raft message exceeded backend quota。告警 NOSPACE 会被触发。

解决:

压缩键空间

命令:

rev=$(docker exec etcd etcdctl endpoint status --write-out json | egrep -o '"revision":[0-9]*' | egrep -o '[0-9]*')
docker exec etcd etcdctl compact "$rev"

输出示例:

compacted revision xxx

对所有 etcd 成员进行碎片整理

命令:

docker exec -e ETCDCTL_ENDPOINTS=$(docker exec etcd etcdctl member list | cut -d, -f5 | sed -e 's/ //g' | paste -sd ',') etcd etcdctl defrag

输出示例:

Finished defragmenting etcd member[https://IP:2379]
Finished defragmenting etcd member[https://IP:2379]
Finished defragmenting etcd member[https://IP:2379]

检查端点状态

命令:

docker exec -e ETCDCTL_ENDPOINTS=$(docker exec etcd etcdctl member list | cut -d, -f5 | sed -e 's/ //g' | paste -sd ',') etcd etcdctl endpoint status --write-out table

输出示例:

+-----------------+------------------+---------+---------+-----------+-----------+------------+
| ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+-----------------+------------------+---------+---------+-----------+-----------+------------+
| https://IP:2379 | e973e4419737125 | 3.5.7 | 553 kB | false | 32 | 2449410 |
| https://IP:2379 | 4a509c997b26c206 | 3.5.7 | 553 kB | false | 32 | 2449410 |
| https://IP:2379 | b217e736575e9dd3 | 3.5.7 | 553 kB | true | 32 | 2449410 |
+-----------------+------------------+---------+---------+-----------+-----------+------------+

解除告警

如果压缩和整理碎片后确定数据库大小下降了,则需要解除告警来允许 etcd 再次写入。

命令:

docker exec etcd etcdctl alarm list
docker exec etcd etcdctl alarm disarm
docker exec etcd etcdctl alarm list

输出示例:

docker exec etcd etcdctl alarm list
memberID:x alarm:NOSPACE
memberID:x alarm:NOSPACE
memberID:x alarm:NOSPACE
docker exec etcd etcdctl alarm disarm
docker exec etcd etcdctl alarm list

配置日志级别

备注

你无法再动态更改 etcd v3.5 或更高版本中的日志级别。

etcd v3.5 及更高版本

要配置 etcd 的日志级别,请编辑集群 YAML:

services:
etcd:
extra_args:
log-level: "debug"

etcd v3.4 及更早版本

在早期的 etcd 版本中,你可以使用 API 动态更改日志级别。使用以下命令来配置调试日志:

docker run --net=host -v $(docker inspect kubelet --format '{{ range .Mounts }}{{ if eq .Destination "/etc/kubernetes" }}{{ .Source }}{{ end }}{{ end }}')/ssl:/etc/kubernetes/ssl:ro appropriate/curl -s -XPUT -d '{"Level":"DEBUG"}' --cacert $(docker exec etcd printenv ETCDCTL_CACERT) --cert $(docker exec etcd printenv ETCDCTL_CERT) --key $(docker exec etcd printenv ETCDCTL_KEY) $(docker exec etcd printenv ETCDCTL_ENDPOINTS)/config/local/log

要将日志级别重置回默认值 (INFO),你可以使用以下命令。

命令:

docker run --net=host -v $(docker inspect kubelet --format '{{ range .Mounts }}{{ if eq .Destination "/etc/kubernetes" }}{{ .Source }}{{ end }}{{ end }}')/ssl:/etc/kubernetes/ssl:ro appropriate/curl -s -XPUT -d '{"Level":"INFO"}' --cacert $(docker exec etcd printenv ETCDCTL_CACERT) --cert $(docker exec etcd printenv ETCDCTL_CERT) --key $(docker exec etcd printenv ETCDCTL_KEY) $(docker exec etcd printenv ETCDCTL_ENDPOINTS)/config/local/log

etcd 内容

如果要查看 etcd 的内容,你可以查看流事件,也可以直接查询 etcd。详情请参阅以下示例。

查看流事件

命令:

docker exec etcd etcdctl watch --prefix /registry

如果你只想查看受影响的键(而不是二进制数据),你可以将 | grep -a ^/registry 尾附到该命令来过滤键。

直接查询 etcd

命令:

docker exec etcd etcdctl get /registry --prefix=true --keys-only

你可以使用以下命令来处理数据,从而获取每个键的计数摘要:

docker exec etcd etcdctl get /registry --prefix=true --keys-only | grep -v ^$ | awk -F'/' '{ if ($3 ~ /cattle.io/) {h[$3"/"$4]++} else { h[$3]++ }} END { for(k in h) print h[k], k }' | sort -nr

更换不健康的 etcd 节点

如果你 etcd 集群中的某个节点变得不健康,在将新的 etcd 节点添加到集群之前,我们建议你修复或删除故障/不健康的节点。