Haproxy + percona 5.7 xtradb error - haproxy

Question

i configure
Hello, I configure haproxy by digitalocean manual, roundrobin for percona 5.7 bases, but on the haproxy server, when I try to connect to the database I getting error.
On the haproxy server:
mysql -h 127.0.0.1 -u haproxy_root -p -e "SHOW DATABASES"
And i get error:
ERROR 2013 (HY000): Lost connection to MySQL server at 'reading initial communication packet', system error: 2
Haproxy config:
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
If I connect directly to the database 192.168.0.101, everything works, I get a response from the database, but when I make the request through to haproxy 127.0.0.1 I get this error:
ERROR 2013 (HY000): Lost connection to MySQL server at 'reading
initial communication packet', system error: 2
My xinetd config on mysql:
# 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
}
If i telnet to PXC node on port 9200, i got:
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

The most common reason for this is that all nodes in the cluster is down. If you have enabled your HAProxy stats, check that all nodes are up. If not, you mysqlchk service is likely not being able to connect to the cluster nodes properly.
Check your mysqlchk xinetd service should have the proper server_args configured. Once these are set, restart xinetd, and telnet to port 9200 to validate
[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"
}
UPDATE:
A more thorough procedure, including making sure mysqlchk is configured, can be found here https://www.percona.com/doc/percona-xtradb-cluster/5.6/howtos/virt_sandbox.html