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xinetd‘对方重置连接’

tag-icon • tag-icon xinetd percona-xtradb-cluster clustercheck
xinetd‘对方重置连接’

我在用着percona-clustercheck（Percona 的 XtraDB Cluster 包附带）和 xinetd，当我尝试 curl clustercheck 服务时出现错误。

/usr/bin/clustercheck：

#!/bin/bash 
#
# Script to make a proxy (ie HAProxy) capable of monitoring Percona XtraDB Cluster nodes properly
#
# Author: Olaf van Zandwijk <[email protected]>
# Documentation and download: https://github.com/olafz/percona-clustercheck
#
# Based on the original script from Unai Rodriguez 
#

MYSQL_USERNAME="clustercheckuser" 
MYSQL_PASSWORD="clustercheckpassword!" 
ERR_FILE="/dev/null" 
AVAILABLE_WHEN_DONOR=0

#
# Perform the query to check the wsrep_local_state
#
WSREP_STATUS=`mysql --user=${MYSQL_USERNAME} --password=${MYSQL_PASSWORD} -e "SHOW STATUS LIKE 'wsrep_local_state';" 2>${ERR_FILE} | awk '{if (NR!=1){print $2}}' 2>${ERR_FILE}` 

if [[ "${WSREP_STATUS}" == "4" ]] || [[ "${WSREP_STATUS}" == "2" && ${AVAILABLE_WHEN_DONOR} == 1 ]]
then 
    # Percona XtraDB Cluster node local state is 'Synced' => return HTTP 200
    /bin/echo -en "HTTP/1.1 200 OK\r\n" 
    /bin/echo -en "Content-Type: text/plain\r\n" 
    /bin/echo -en "\r\n" 
    /bin/echo -en "Percona XtraDB Cluster Node is synced.\r\n" 
    /bin/echo -en "\r\n" 
    exit 0
else 
    # Percona XtraDB Cluster node local state is not 'Synced' => return HTTP 503
    /bin/echo -en "HTTP/1.1 503 Service Unavailable\r\n" 
    /bin/echo -en "Content-Type: text/plain\r\n" 
    /bin/echo -en "\r\n" 
    /bin/echo -en "Percona XtraDB Cluster Node is not synced.\r\n" 
    /bin/echo -en "\r\n"
    exit 1 
fi

/etc/xinetd.mysqlchk：

# default: on
# description: mysqlchk
service mysqlchk
{
# this is a config for xinetd, place it in /etc/xinetd.d/
  disable = no
  flags = REUSE
  socket_type = stream
  port = 9200
  wait = no
  user = nobody
  server = /usr/bin/clustercheck
  log_on_failure += USERID
  only_from = 10.0.0.0/8 127.0.0.1
  # recommended to put the IPs that need
  # to connect exclusively (security purposes)
  per_source = UNLIMITED
}

当尝试卷曲服务时，我得到了有效的响应（HTTP 200，文本），但最后出现了“对等方重置连接”通知：

HTTP/1.1 200 OK
Content-Type: text/plain

Percona XtraDB Cluster Node is synced.

curl: (56) Recv failure: Connection reset by peer

不幸的是，Amazon ELB 似乎将此视为一次失败的检查，而不是一次成功的检查。

如何才能让 clustercheck 正常退出，以使 curl 不会看到连接失败？

答案1

添加Content-Length: 0会使客户端忽略内容，即使有内容（如本例中所示）。因此这可能会破坏其他检查软件。在您的例子中，Content-Length: 42同步节点的内容长度为 42 字节（因此添加），未同步节点的内容长度为 46 字节。

# curl localhost:9200
Percona XtraDB Cluster Node is synced.

我将推送更新的脚本，以便它也将在新版本的 Percona XtraDB Cluster 包中得到修复。

答案2

我Content-Length: 0在 clustercheck 响应中添加了一个标头，这似乎对 Amazon 的健康检查起了作用。如果有人有更好的做法，请告诉我

答案3

我解决了类似的问题使用

echo -en "HTTP/1.1 200 OK\r\n" | cat

反而

echo -en "HTTP/1.1 200 OK\r\n"

答案4

我还注意到您正在 localhost 上使用脚本。您还可以在命令行上执行 clustercheck 并检查返回值。

如果是同步节点：

# /usr/bin/clustercheck > /dev/null
# echo $?
0

如果节点未同步：

# /usr/bin/clustercheck > /dev/null
# echo $?
1

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