# MTU in calico

**URL:** <https://discuss.kubernetes.io/t/mtu-in-calico/15618>\
**Category:** microk8s\
**Tags:** network\
**Created:** [April 21, 2021, 11:17am UTC](https://discuss.kubernetes.io/t/mtu-in-calico/15618 "2021-04-21T11:17:08Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![rubick](https://avatars.discourse-cdn.com/v4/letter/r/4bbf92/32.png) [@rubick](https://discuss.kubernetes.io/u/rubick)\
**Post date:** [April 21, 2021, 11:17am UTC](https://discuss.kubernetes.io/t/mtu-in-calico/15618/1 "2021-04-21T11:17:08Z")

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Hello,  
I want to change the MTU used by my pods.  
Following [Configure MTU to maximize network performance](https://docs.projectcalico.org/networking/mtu) I am able to do that by changing the veth\_mtu. However, I found that the vxlan.calico interface on the bare-metal machine that hosts the pods is still 1410, which hurts performance.  
I also tried to edit the `mtu` field using `kubectl edit cm calico-config -n kube-system` but to no avail.  
Any suggestions? Thank you

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**Author:** ![balchua1](https://sea2.discourse-cdn.com/flex016/user_avatar/discuss.kubernetes.io/balchua1/32/5372_2.png) [@balchua1](https://discuss.kubernetes.io/u/balchua1)\
**Post date:** [April 21, 2021, 1:01pm UTC](https://discuss.kubernetes.io/t/mtu-in-calico/15618/2 "2021-04-21T13:01:19Z")

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You did restart the `calico-node`

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<div class="post-metadata">

**Author:** ![rubick](https://avatars.discourse-cdn.com/v4/letter/r/4bbf92/32.png) [@rubick](https://discuss.kubernetes.io/u/rubick)\
**Post date:** [April 21, 2021, 1:25pm UTC](https://discuss.kubernetes.io/t/mtu-in-calico/15618/3 "2021-04-21T13:25:44Z")

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> [@balchua1](#):
>
> calico-nod

Hello, yes I have restarted the whole microk8s service with `microk8s stop && microk8s start`.  
Is what I did correct? Thank you

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**Author:** ![balchua1](https://sea2.discourse-cdn.com/flex016/user_avatar/discuss.kubernetes.io/balchua1/32/5372_2.png) [@balchua1](https://discuss.kubernetes.io/u/balchua1)\
**Post date:** [April 21, 2021, 1:43pm UTC](https://discuss.kubernetes.io/t/mtu-in-calico/15618/4 "2021-04-21T13:43:40Z")

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Yup. That will do.

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<div class="post-metadata">

**Author:** ![balchua1](https://sea2.discourse-cdn.com/flex016/user_avatar/discuss.kubernetes.io/balchua1/32/5372_2.png) [@balchua1](https://discuss.kubernetes.io/u/balchua1)\
**Post date:** [April 21, 2021, 9:27pm UTC](https://discuss.kubernetes.io/t/mtu-in-calico/15618/5 "2021-04-21T21:27:05Z")

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I forgot to ask, did you change the mtu of the host’s network interface you are using?

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**Author:** ![rubick](https://avatars.discourse-cdn.com/v4/letter/r/4bbf92/32.png) [@rubick](https://discuss.kubernetes.io/u/rubick)\
**Post date:** [April 22, 2021, 5:21am UTC](https://discuss.kubernetes.io/t/mtu-in-calico/15618/6 "2021-04-22T05:21:25Z")

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Hi @balchua1 this was indeed my issue. I manage to change the MTU in the pod by changing the `veth_mtu` field, but not the MTU on the virtual interface on the host.  
Apparently, I have to change the env `FELIX_VXLANMTU` for that to happen, by editing the calico-node daemonset.  
If you have any other way of doing it please let me know.