Comment # 26 on bug 1171770 from Richard Brown

(In reply to Richard Brown from comment #25)
> (In reply to Rafael Fern�ndez L�pez from comment #22)
> > I have the impression that `net.ipv6.conf.all.forwarding = 0` being set by
> > `/etc/sysctl.d/70-yast.conf` has an impact here.
> > 
> > I did override this setting by creating a `/etc/sysctl.d/91-kubeadm.conf`
> > file with contents:
> > 
> > ```
> > net.ipv4.ip_forward = 1
> > net.ipv6.conf.all.forwarding = 1
> > ```
> > 
> > After rebooting the node, everything works fine. As Richard mentioned,
> > removing `/etc/sysctl.d/70-yast.conf` altogether and rebooting also makes
> > the trick.
> > 
> > This makes me think that the override in `/usr/lib/sysctl.d/90-kubeadm.conf`
> > is not enough, it currently has:
> > 
> > ```
> > # The file is provided as part of the kubernetes-kubeadm package
> > net.ipv4.ip_forward = 1
> > ```
> > 
> > From what I see, it should include `net.ipv6.conf.all.forwarding = 1` as
> > well. I cannot explain why this is happening in a better way right now
> > though.
> 
> I tried this before making my post, and it didn't work for me..but I trust
> your observation also so I'm putting it in a patch for kubernetes1.18 and
> kubernetes1.17 and testing those packages :)
> 
> thanks!

Put the change in the package, and confirmed - it does not work to add
`net.ipv6.conf.all.forwarding = 1`

However, I can confirm, if I copy 90-kubeadm.conf to /etc/sysctl.d, then it
works.

This means something is incorrectly parsing/not parsing /usr/share/sysctl.d

Now we just need to figure out what