You can do SSH to Edge & DLR Control VM & using CLI you will be able to check the logs. Even you have use NSX Manager Central CLI to check the relevant logs.
What kind of log you are expecting to look for, cause it depends on what type of logging you have enabled.
As mentioned by rajeevsrikant you can:
1. SSH into the Edge VM and do a show log
2. Use Central CLI from NSX Manager and do a show edge <edge-ID> log
3. or download a tech support log
This is also explained on NSX doc below
VMware Documentation Library - NSX Logs Relevant to Routing
ESG/DLR Control VM Logs
There are two ways to access log files on the ESG and DLR Control VMs—to display them using a CLI or to download the tech support bundle, using the CLI or UI.
The CLI command to display logs is show log [ follow | reverse ].
To download tech-support bundle:
- From the CLI, enter enable mode, then run the export tech-support <[ scp | ftp ]> <URI> command.
- From the vSphere Web Client, select the Download Tech Support Logs option in the Actions menu.
While not strictly logs, there are a number of files that can be helpful in understanding and troubleshooting NSX routing.
- The control plane agent configuration, /etc/vmware/netcpa/config-by-vsm.xml contains the information about the following components:
- Controllers, IP addresses, TCP ports, certificate thumbprints, SSL enable/disable
- dvUplinks on the DVS enabled with VXLAN (teaming policy, names, UUID)
- DLR instances the host knows about (DLR ID, name)
- The control plane agent configuration, /etc/vmware/netcpa/netcpa.xml contains various configuration options for netcpa, including logging level (which by default is info).
- Control plane certificate files: /etc/vmware/ssl/rui-for-netcpa.*
- Two files: host certificate and host private key
- Used for authenticating host connections to Controllers
VMware Documentation Library - Checking Logical Routing—Log Files from Hosts
You could also use a centralised syslog server and send all your logs to the syslog server for example to vRealize Log Insight
If you have NSX License, you are eligible for vRealize Log Insight license
Log Insight for NSX Frequently Asked Questions (FAQ) - VMware Cloud Management
"VMware announced that all users with a NSX 6.2.3 (and beyond) license are now entitled to vRealize Log Insight for NSX at no additional charge. Read the full NSX 6.2.3 announcement here. "
To configure syslog server settings on NSX, see below docs:
- NSX Manager & NSX Edge (including Control VM) - VMware Documentation Library-Configuring a Syslog Server
- NSX Controller - Configuring syslog server for VMware NSX for vSphere 6.x controllers (2092228) | VMware KB
