mirror of https://github.com/linkerd/linkerd2.git
332c4efa8c
## Problem
When the IPv6 stack in Linux is disabled, the proxy will crash at startup.
## Repro
In a Linux machine, disable IPv6 networking through the `net.ipv6.conf.*` sysctl kernel tunables, and restart the system:
- In /etc/sysctl.conf add:
```
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
```
- In /etc/default/grub set:
```
GRUB_CMDLINE_LINUX="ipv6.disable=1"
```
- Don't forget to update grub before rebooting:
```
sudo update-grub
```
In a default k3d cluster, install Linkerd. You should see the following error in any proxy log:
```
thread 'main' panicked at /__w/linkerd2-proxy/linkerd2-proxy/linkerd/app/src/lib.rs:245:14:
Failed to bind inbound listener: Os { code: 97, kind: Uncategorized, message: "Address family not supported by protocol" }
```
## Cause
Even if a k8s cluster didn't support IPv6, we were counting on the nodes having an IPv6 stack, which allowed us to bind to the inbound proxy to [::] (although not to [::1] for the outbound proxy, as seen in GKE). This was the case in the major cloud providers we tested, but it turns out there are folks running nodes with IPv6 disabled and so we have to cater that case as well.
## Fix
The current change undoes some of the changes from
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