Basically, EXOS switch does not generate any debug level logs.
Any changes in the routing table is logged with debug level, so you will not see them.
To enable log debug mode, below command is needed.
enable log debug-mode
But still you should add which log component to be logged on ems configuration.
Checking out log counters will lead you what component you'd like to add.
For an example, below is a log counters of RtMgr.WalkInfoAdd on which I think you're intersted.
* EXTR-8F-EXSi-LAB-Core.51 # show log counters RtMgr.WalkInfoAdd
Component SubComponent Condition Severity Occurred I Ntfd Last Notified Time
----------- ------------ ----------------------- ------------- -------- - ---- ----------------------
RtMgr WalkInfoAdd Debug-Data 91 Y 49 11/23/2018 10:28:35.20
If you see counters increased here, you can add that component with a CLI command below.
configure log filter DefaultFilter add events RtMgr.WalkInfoAdd Then you will see some related logs like,
11/23/2018 10:28:35.20 Walker added RT Dest=10.254.8.0/24 via 10.254.8.1 vr=2; rtFlags=U------um--f-(0x3c01) NotifFlgs=-----------------O(0x1) rtOrigin=Direct rtMetric=1 rtTTL=0 ifIndex=0xf4246 clntId=0x20056 State=0x0 for vr=2 walker-entries=3 walker-index=4 walker-maxEntries=8 state=011/23/2018 10:28:35.20 Walker added RT Dest=10.223.31.0/24 via 10.223.31.1 vr=2; rtFlags=-------um----(0xc00) NotifFlgs=-----------------O(0x1) rtOrigin=Direct rtMetric=1 rtTTL=0 ifIndex=0xf427a clntId=0x20056 State=0x0 for vr=2 walker-entries=2 walker-index=3 walker-maxEntries=8 state=0