canal 不知道因为什么原因挂掉了，重启的话，adapter 端日志也显示启动正常，找了半天是因为 canalserver 端的配置出现问题，conf 目录下的 meta.dat 文件读取的文件不存在，错误日志是这样的：

2019-09-15 23:59:21.853 [destination = testcore , address = /172.18.108.67:3306 , EventParser] WARN  c.a.o.c.p.inbound.mysql.rds.RdsBinlogEventParserProxy - ---> begin to find start position, it will be long time for reset or first position
2019-09-15 23:59:21.854 [destination = testcore , address = /172.18.108.67:3306 , EventParser] WARN  c.a.o.c.p.inbound.mysql.rds.RdsBinlogEventParserProxy - prepare to find start position just last position
 {"identity":{"slaveId":-1,"sourceAddress":{"address":"172.18.108.67","port":3306}},"postion":	{"gtid":"","included":false,"journalName":"mysql-bin.000030","position":832575421,"serverId":10867,"timestamp":1567176390000}}
2019-09-15 23:59:21.855 [destination = testcore , address = /172.18.108.67:3306 , EventParser] WARN  c.a.o.c.p.inbound.mysql.rds.RdsBinlogEventParserProxy - ---> find start position successfully, EntryPosition[included=false,journalName=mysql-bin.000030,position=832575421,serverId=10867,gtid=,timestamp=1567176390000] cost : 2ms , the next step is binlog dump
2019-09-15 23:59:21.857 [destination = testcore , address = /172.18.108.67:3306 , EventParser] ERROR c.a.o.canal.parse.inbound.mysql.dbsync.DirectLogFetcher - I/O error while reading from client socket
java.io.IOException: Received error packet: errno = 1236, sqlstate = HY000 errmsg = Could not find first log file name in binary log index file
    at com.alibaba.otter.canal.parse.inbound.mysql.dbsync.DirectLogFetcher.fetch(DirectLogFetcher.java:102) ~[canal.parse-1.1.3.jar:na]
    at com.alibaba.otter.canal.parse.inbound.mysql.MysqlConnection.dump(MysqlConnection.java:235) [canal.parse-1.1.3.jar:na]
    at com.alibaba.otter.canal.parse.inbound.AbstractEventParser$3.run(AbstractEventParser.java:257) [canal.parse-1.1.3.jar:na]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_111]
2019-09-15 23:59:21.857 [destination = testcore , address = /172.18.108.67:3306 , EventParser] ERROR 	c.a.o.c.p.inbound.mysql.rds.RdsBinlogEventParserProxy - dump address /172.18.108.67:3306 has an error, retrying. caused by 
java.io.IOException: Received error packet: errno = 1236, sqlstate = HY000 errmsg = Could not find first log file name in binary log index file
    at com.alibaba.otter.canal.parse.inbound.mysql.dbsync.DirectLogFetcher.fetch(DirectLogFetcher.java:102) ~[canal.parse-1.1.3.jar:na]
    at com.alibaba.otter.canal.parse.inbound.mysql.MysqlConnection.dump(MysqlConnection.java:235) ~[canal.parse-1.1.3.jar:na]
    at com.alibaba.otter.canal.parse.inbound.AbstractEventParser$3.run(AbstractEventParser.java:257) ~[canal.parse-1.1.3.jar:na]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_111]
2019-09-15 23:59:21.857 [destination = testcore , address = /172.18.108.67:3306 , EventParser] ERROR com.alibaba.otter.canal.common.alarm.LogAlarmHandler - destination:testcore[java.io.IOException: Received error packet: errno = 1236, sqlstate = HY000 errmsg = Could not find first log file name in binary log index file
    at com.alibaba.otter.canal.parse.inbound.mysql.dbsync.DirectLogFetcher.fetch(DirectLogFetcher.java:102)
    at com.alibaba.otter.canal.parse.inbound.mysql.MysqlConnection.dump(MysqlConnection.java:235)
    at com.alibaba.otter.canal.parse.inbound.AbstractEventParser$3.run(AbstractEventParser.java:257)
    at java.lang.Thread.run(Thread.java:745)

]

需要把 meta.dat 文件删除，然后重启 canalserver ，重新匹配日志文件读取才正常。