Haproxy + percona 5.7 xtradb错误

Question

我配置了Hello，我通过数字海洋手册配置haproxy，为Percona5.7基础配置roundrobin，但是在haproxy服务器上，当我试图连接到数据库时会出错。

在haproxy服务器上：

mysql -h 127.0.0.1 -u haproxy_root -p -e "SHOW DATABASES"

我得到了错误：

ERROR 2013 (HY000): Lost connection to MySQL server at 'reading initial communication packet', system error: 2

Haproxy配置：

    lobal
        log 127.0.0.1   local0
        log 127.0.0.1   local1 notice
        #log loghost    local0 info
        maxconn 1024
        #chroot /usr/share/haproxy
        user haproxy
        group haproxy
        daemon
        #debug
        #quiet


defaults
        log     global
        mode    http
        option  tcplog
        option  dontlognull
        retries 3
        option redispatch
        maxconn 1024
        timeout connect 5000ms
        timeout client 50000ms
        timeout server 50000ms

listen galera_cluster
        bind 127.0.0.1:3306
        mode tcp
        option  httpchk
        balance leastconn
        server galera-node01 192.168.0.101:3306 check port 9200
        server galera-node02 192.168.0.102:3306 check port 9200
        server galera-node03 192.168.0.103:3306 check port 9200

如果我直接连接到数据库192.168.0.101，一切正常，我会从数据库得到一个响应，但是当我通过haproxy 127.0.0.1发出请求时，会得到以下错误：

ERROR 2013 (HY000)：在“读取初始通信包”时丢失与MySQL服务器的连接，系统错误:2

我在mysql上的xinetd配置：

# 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
        type            = UNLISTED
        port            = 9200
        wait            = no
        user            = nobody
        server          = /usr/bin/clustercheck
        server_args = percona percona
        log_on_failure  += USERID
        only_from       = 0.0.0.0/0
        #
        # Passing arguments to clustercheck
        # <user> <pass> <available_when_donor=0|1> <log_file> <available_when_readonly=0|1> <defaults_extra_file>"
        # Recommended: server_args   = user pass 1 /var/log/log-file 0 /etc/my.cnf.local"
        # Compatibility: server_args = user pass 1 /var/log/log-file 1 /etc/my.cnf.local"
        # 55-to-56 upgrade: server_args = user pass 1 /var/log/log-file 0 /etc/my.cnf.extra"
        #
        # recommended to put the IPs that need
        # to connect exclusively (security purposes)
        per_source      = UNLIMITED
}

如果我在9200端口上向PXC节点发了电话，就会得到：

telnet 192.168.0.101 9200
Trying 192.168.0.101...
Connected to 192.168.0.101.
Escape character is '^]'.
HTTP/1.1 503 Service Unavailable
Content-Type: text/plain
Connection: close
Content-Length: 57

Percona XtraDB Cluster Node is not synced or non-PRIM.
Connection closed by foreign host.

Answer 1

最常见的原因是集群中的所有节点都关闭了。如果启用了HAProxy统计数据，请检查所有节点是否已启动。否则，mysqlchk服务很可能无法正确连接到群集节点。

检查mysqlchk xinetd服务应该配置了正确的server_args。设置这些后，重新启动xinetd，并将telnet重新启动到端口9200以进行验证。

[root@node02 log]# cat /etc/xinetd.d/mysqlchk
# default: on
# description: mysqlchk
service mysqlchk
{
# this is a config for xinetd, place it in /etc/xinetd.d/
        ...
        server          = /usr/bin/clustercheck
        server_args = percona percona
        ...
        # Passing arguments to clustercheck
        # <user> <pass> <available_when_donor=0|1> <log_file> <available_when_readonly=0|1> <defaults_extra_file>"
        # Recommended: server_args   = user pass 1 /var/log/log-file 0 /etc/my.cnf.local"
}

更新：

一个更彻底的过程，包括确保mysqlchk配置，可以在这里找到sandbox.html。