Only bind to IPv6 addresses when disableIPv6=false #12938
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
## 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 7cbe2f5 (for the proxy config), 7cbe2f5 (for the policy controller) and 6603409 (for linkerd-cni), binding back again to 0.0.0.0 unless `disableIPv6` is false.
adleong
approved these changes
Aug 5, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
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 a default k3d cluster, install Linkerd. You should see the following error in any proxy log:
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 7cbe2f5 (for the proxy config), 7cbe2f5 (for the policy controller) and 6603409 (for linkerd-cni), binding back again to 0.0.0.0 unless
disableIPv6is false.