edit the grastate.dat file manually and set safe_to_bootstrap to 1

1、嘗試重啟mysql資料庫時報錯
[root@galera01 ~]# /etc/init.d/mysqld start  --wsrep-new-cluster
MySQL Daemon failed to start.
Starting mysqld:  [FAILED]

2、檢視啟動報錯日誌
2017-07-24T02:45:41.972508Z 0 [ERROR] WSREP: It may not be safe to bootstrap the cluster from this node. It was not the last one to leave the cluster and may not contain all the
 updates. To force cluster bootstrap with this node, edit the grastate.dat file manually and set safe_to_bootstrap to 1 .
2017-07-24T02:45:41.972511Z 0 [ERROR] WSREP: wsrep::connect(gcomm://192.168.56.111,192.168.56.112,192.168.56.113) failed: 7
2017-07-24T02:45:41.972513Z 0 [ERROR] Aborting

2017-07-24T02:45:41.972516Z 0 [Note] Giving 0 client threads a chance to die gracefully
2017-07-24T02:45:41.972519Z 0 [Note] WSREP: Service disconnected.
2017-07-24T02:45:42.972895Z 0 [Note] WSREP: Some threads may fail to exit.
2017-07-24T02:45:42.972937Z 0 [Note] Binlog end
2017-07-24T02:45:42.973014Z 0 [Note] /usr/sbin/mysqld: Shutdown complete

3、嘗試先啟動其他節點，相同報錯
從錯誤日誌提示報錯提示，當前節點不是叢集中最後離開的節點，也就是說當前節點可能未能包含所有的更新。
如果強制啟動當前節點，需要修改grastate.dat檔案將safe_to_bootstrap的值置為1。
嘗試先啟動其他節點，相同報錯。

4、修改grastate.dat檔案
該檔案主要描述GALERA保持的狀態資訊，按指引修改safe_to_bootstrap的值置為1。
# cat grastate.dat
# GALERA saved state
version: 2.1
uuid:    df4a1da6-701a-11e7-87fe-e6c3a440d1ec
seqno:   -1
safe_to_bootstrap: 1               ---由原來的0修改為1再次啟動

# /etc/init.d/mysqld start  --wsrep-new-cluster
Starting mysqld:  [  OK  ]
5、mysql叢集啟動成功

mysql> show global status like 'wsrep%';
+------------------------------+-------------------------------------------------------------+
| Variable_name                | Value                                                       |
+------------------------------+-------------------------------------------------------------+
| wsrep_local_state_uuid       | df4a1da6-701a-11e7-87fe-e6c3a440d1ec                        |
| wsrep_protocol_version       | 7                                                           |
| wsrep_last_committed         | 0                                                           |
| wsrep_replicated             | 0                                                           |
| wsrep_replicated_bytes       | 0                                                           |
| wsrep_repl_keys              | 0                                                           |
| wsrep_repl_keys_bytes        | 0                                                           |
| wsrep_repl_data_bytes        | 0                                                           |
| wsrep_repl_other_bytes       | 0                                                           |
| wsrep_received               | 10                                                          |
| wsrep_received_bytes         | 752                                                         |
| wsrep_local_commits          | 0                                                           |
| wsrep_local_cert_failures    | 0                                                           |
| wsrep_local_replays          | 0                                                           |
| wsrep_local_send_queue       | 0                                                           |
| wsrep_local_send_queue_max   | 1                                                           |
| wsrep_local_send_queue_min   | 0                                                           |
| wsrep_local_send_queue_avg   | 0.000000                                                    |
| wsrep_local_recv_queue       | 0                                                           |
| wsrep_local_recv_queue_max   | 1                                                           |
| wsrep_local_recv_queue_min   | 0                                                           |
| wsrep_local_recv_queue_avg   | 0.000000                                                    |
| wsrep_local_cached_downto    | 18446744073709551615                                        |
| wsrep_flow_control_paused_ns | 0                                                           |
| wsrep_flow_control_paused    | 0.000000                                                    |
| wsrep_flow_control_sent      | 0                                                           |
| wsrep_flow_control_recv      | 0                                                           |
| wsrep_cert_deps_distance     | 0.000000                                                    |
| wsrep_apply_oooe             | 0.000000                                                    |
| wsrep_apply_oool             | 0.000000                                                    |
| wsrep_apply_window           | 0.000000                                                    |
| wsrep_commit_oooe            | 0.000000                                                    |
| wsrep_commit_oool            | 0.000000                                                    |
| wsrep_commit_window          | 0.000000                                                    |
| wsrep_local_state            | 4                                                           |
| wsrep_local_state_comment    | Synced                                                      |
| wsrep_cert_index_size        | 0                                                           |
| wsrep_causal_reads           | 0                                                           |
| wsrep_cert_interval          | 0.000000                                                    |
| wsrep_incoming_addresses     | 192.168.56.111:3306,192.168.56.112:3306,192.168.56.113:3306 |
| wsrep_desync_count           | 0                                                           |
| wsrep_evs_delayed            |                                                             |
| wsrep_evs_evict_list         |                                                             |
| wsrep_evs_repl_latency       | 0/0/0/0/0                                                   |
| wsrep_evs_state              | OPERATIONAL                                                 |
| wsrep_gcomm_uuid             | df49c18f-701a-11e7-aaaa-9659aa7ef9f8                        |
| wsrep_cluster_conf_id        | 3                                                           |
| wsrep_cluster_size           | 3                                                           |
| wsrep_cluster_state_uuid     | df4a1da6-701a-11e7-87fe-e6c3a440d1ec                        |
| wsrep_cluster_status         | Primary                                                     |
| wsrep_connected              | ON                                                          |
| wsrep_local_bf_aborts        | 0                                                           |
| wsrep_local_index            | 0                                                           |
| wsrep_provider_name          | Galera                                                      |
| wsrep_provider_vendor        | Codership Oy                            |
| wsrep_provider_version       | 3.20(r7e383f7)                                              |
| wsrep_ready                  | ON                                                          |
+------------------------------+-------------------------------------------------------------+
57 rows in set (0.00 sec)

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