From 37f00a38827ddd775513b46b548cc507ff4f74b3 Mon Sep 17 00:00:00 2001 From: Dalton Hubble Date: Thu, 18 Jun 2020 23:47:35 -0700 Subject: [PATCH] Reduce Calcio MTU on Fedora CoreOS Azure * Change the Calico VXLAN interface for MTU from 1450 to 1410 * VXLAN on Azure should support MTU 1450. However, there is history where performance measures have shown that 1410 is needed to have expected performance. Flatcar Linux has the same MTU 1410 override and note * FCOS 31.20200323.3.2 was known to perform fine with 1450, but now in 31.20200517.3.0 the right value seems to be 1410 --- CHANGES.md | 1 + azure/fedora-coreos/kubernetes/bootstrap.tf | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/CHANGES.md b/CHANGES.md index f35e44fe..af856a57 100644 --- a/CHANGES.md +++ b/CHANGES.md @@ -26,6 +26,7 @@ Notable changes between versions. #### Azure * Use `strict` Fedora CoreOS Config (FCC) snippet parsing ([#755](https://github.com/poseidon/typhoon/pull/755)) +* Reduce Calico vxlan interface MTU to maintain performance ([#767](https://github.com/poseidon/typhoon/pull/766)) #### AWS diff --git a/azure/fedora-coreos/kubernetes/bootstrap.tf b/azure/fedora-coreos/kubernetes/bootstrap.tf index 76391f6e..6e8d6e79 100644 --- a/azure/fedora-coreos/kubernetes/bootstrap.tf +++ b/azure/fedora-coreos/kubernetes/bootstrap.tf @@ -10,8 +10,9 @@ module "bootstrap" { networking = var.networking # only effective with Calico networking + # we should be able to use 1450 MTU, but in practice, 1410 was needed network_encapsulation = "vxlan" - network_mtu = "1450" + network_mtu = "1410" pod_cidr = var.pod_cidr service_cidr = var.service_cidr