GitHub user lexmora closed a discussion: VXLAN: Loss of Connectivity Between
Two VMs After Idle Time on KVM Hosts – CloudStack 4.20
**Description:**
Hello,
I hope you're doing well, I've recently returned to using CloudStack after a
few years, and I'm currently facing a VXLAN connectivity issue **between two
virtual machine**s deployed on different KVM hosts.
**Issue Summary:**
- Two VM's are deployed on separate KVM Hosts.
- VXLAN bridges and interfaces are correctly created by CLoudStack.
- Initial connectivity work fine -- VM's can ping each other and the gateway
(Virtual Router).
- After stopping traffic between them and waiting appoximately 5 minutes, **the
VMs can no loger communicate with each other.**
- The issue affects both directions (bi'directional connectivity loss).
- The _bridge fdb show_ command no longer shows the remote MAC addresses
associated with the VXLAN interface.
- This leads to traffic being dropped, and ping fails to resume.
**Temporary Workaround:**
The only way to restore traffic is by manually bringing down and up the
physical interface on the bond carrying the VXLAN traffic.
**Environment Details:**
- 3 KVM Hosts (Kernel 6.2.0)
- CloudStack version 4.20.0.0
- Advaced Zone
- Traffic types configured:
- Management: VLAN
- Storage: VLAN
- Guest: VXLAN
- public VLAN
- VXLAN is configured using multicast
- Native Linux bridge is in use (not OVS)
- IGMP Snooping is disable on the physical switches
Concers and Question:
Why does VXLAN stop learning or maintaining remote VM MAC addresses after idle
time?
is this a know issue with VXLAN multicast setup?
Are there kernel or bridge parameters that should be adjusted (e.g., aging
time)?
Thanks you in advance for your help and support
GitHub link: https://github.com/apache/cloudstack/discussions/10929
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