HAproxy always got Layer7 timeout error

MySQL & MariaDB Percona XtraDB Cluster 5.x
1

HI ,all.Today we got haproxy erro.health checking alway got issue.
Oct 24 10:45:22 localhost haproxy[6645]: Server mysqlcluster_back/172.29.9.43 is DOWN, reason: Layer7 timeout, check duration: 10000ms. 2 active and 0 backup servers left. 52 sessions active, 0 requeued, 0 remaining in queue.
Oct 24 10:45:23 localhost haproxy[6645]: 172.29.9.168:52607 [24/Oct/2017:09:44:52.703] mysqlcluster_front mysqlcluster_back/172.29.9.43 1/0/3631004 141694 – 126/126/126/51/0 0/0
Oct 24 10:45:32 localhost haproxy[6645]: Server mysqlcluster_back/172.29.9.41 is DOWN, reason: Layer7 timeout, check duration: 10001ms. 1 active and 0 backup servers left. 1 sessions active, 0 requeued, 0 remaining in queue.

did the wsrep flow issue? below was noed 1 statu:
mysql> SHOW global status LIKE ‘wsrep%’;
±-----------------------------±-------------------------------------+
| Variable_name | Value |
±-----------------------------±-------------------------------------+
| wsrep_local_state_uuid | 71ff9701-81a2-11e7-aa25-5f865e134a58 |
| wsrep_protocol_version | 5 |
| wsrep_last_committed | 3856332 |
| wsrep_replicated | 1028082 |
| wsrep_replicated_bytes | 15409655941 |
| wsrep_repl_keys | 35038492 |
| wsrep_repl_keys_bytes | 304259744 |
| wsrep_repl_data_bytes | 11031049224 |
| wsrep_repl_other_bytes | 0 |
| wsrep_received | 2926806 |
| wsrep_received_bytes | 100038333458 |
| wsrep_local_commits | 1027658 |
| wsrep_local_cert_failures | 70 |
| wsrep_local_replays | 3 |
| wsrep_local_send_queue | 0 |
| wsrep_local_send_queue_avg | 0.000119 |
| wsrep_local_recv_queue | 0 |
| wsrep_local_recv_queue_avg | 5.928093 |
| wsrep_local_cached_downto | 3844334 |
| wsrep_flow_control_paused_ns | 17185811253435 |
| wsrep_flow_control_paused | 0.002885 |
| wsrep_flow_control_sent | 28 |
| wsrep_flow_control_recv | 48 |
| wsrep_cert_deps_distance | 25.061500 |
| wsrep_apply_oooe | 0.006056 |
| wsrep_apply_oool | 0.000286 |
| wsrep_apply_window | 1.020095 |
| wsrep_commit_oooe | 0.000000 |
| wsrep_commit_oool | 0.000038 |
| wsrep_commit_window | 1.015331 |
| wsrep_local_state | 4 |
| wsrep_local_state_comment | Synced |
| wsrep_cert_index_size | 3700 |
| wsrep_causal_reads | 466723080 |
| wsrep_cert_interval | 0.527902 |
| wsrep_incoming_addresses | , |
| wsrep_cluster_conf_id | 9 |
| wsrep_cluster_size | 3 |
| wsrep_cluster_state_uuid | 71ff9701-81a2-11e7-aa25-5f865e134a58 |
| wsrep_cluster_status | Primary |
| wsrep_connected | ON |
| wsrep_local_bf_aborts | 1961 |
| wsrep_local_index | 2 |
| wsrep_provider_name | Galera |
| wsrep_provider_vendor | Codership Oy <info@codership.com> |
| wsrep_provider_version | 3.5(r178) |
| wsrep_ready | ON |

2

Oct 24 10:44:45 osspclu1 xinetd[2126]: EXIT: mysqlchk status=0 pid=21217 duration=0(sec)
Oct 24 10:44:57 osspclu1 xinetd[2126]: START: mysqlchk pid=21225 from=::ffff:172.29.100.103
Oct 24 10:44:57 osspclu1 xinetd[2126]: EXIT: mysqlchk status=0 pid=21225 duration=0(sec)
Oct 24 10:45:09 osspclu1 xinetd[2126]: START: mysqlchk pid=21233 from=::ffff:172.29.100.103
Oct 24 10:45:09 osspclu1 xinetd[2126]: EXIT: mysqlchk status=0 pid=21233 duration=0(sec)
Oct 24 10:45:21 osspclu1 xinetd[2126]: START: mysqlchk pid=21244 from=::ffff:172.29.100.103
Oct 24 10:45:43 osspclu1 xinetd[2126]: START: mysqlchk pid=21254 from=::ffff:172.29.100.103
Oct 24 10:45:51 osspclu1 xinetd[2126]: EXIT: mysqlchk signal=13 pid=21244 duration=30(sec)
Oct 24 10:46:05 osspclu1 xinetd[2126]: START: mysqlchk pid=21264 from=::ffff:172.29.100.103
Oct 24 10:46:13 osspclu1 xinetd[2126]: EXIT: mysqlchk signal=13 pid=21254 duration=30(sec)
Oct 24 10:46:27 osspclu1 xinetd[2126]: START: mysqlchk pid=21274 from=::ffff:172.29.100.103
Oct 24 10:46:35 osspclu1 xinetd[2126]: EXIT: mysqlchk signal=13 pid=21264 duration=30(sec)
Oct 24 10:46:49 osspclu1 xinetd[2126]: START: mysqlchk pid=21285 from=::ffff:172.29.100.103
Oct 24 10:46:57 osspclu1 xinetd[2126]: EXIT: mysqlchk signal=13 pid=21274 duration=30(sec)
Oct 24 10:47:08 osspclu1 xinetd[2126]: EXIT: mysqlchk signal=13 pid=21285 duration=19(sec)
Oct 24 10:47:11 osspclu1 xinetd[2126]: START: mysqlchk pid=21296 from=::ffff:172.29.100.103
Oct 24 10:47:12 osspclu1 xinetd[2126]: EXIT: mysqlchk status=0 pid=21296 duration=1(sec)
Oct 24 10:47:24 osspclu1 xinetd[2126]: START: mysqlchk pid=21305 from=::ffff:172.29.100.103
Oct 24 10:47:24 osspclu1 xinetd[2126]: EXIT: mysqlchk status=0 pid=21305 duration=0(sec)
Oct 24 10:47:36 osspclu1 xinetd[2126]: START: mysqlchk pid=21313 from=::ffff:172.29.100.103
Oct 24 10:47:36 osspclu1 xinetd[2126]: EXIT: mysqlchk status=0 pid=21313 duration=0(sec)
Oct 24 10:47:48 osspclu1 xinetd[2126]: START: mysqlchk pid=21321 from=::ffff:172.29.100.103
Oct 24 10:47:48 osspclu1 xinetd[2126]: EXIT: mysqlchk status=0 pid=21321 duration=0(sec)
Oct 24 10:48:00 osspclu1 xinetd[2126]: START: mysqlchk pid=21331 from=::ffff:172.29.100.103