Problem
When deploying DKP 2.x in an on premise environment with IPv6 disabled from the kernel, it is possible that the step would fail where the Konvoy Image Builder (KIB) attempts to modify net.ipv6.conf.all.forwarding by setting the value in the file /proc/sys/net/ipv6/conf/all/forwarding.
The provisioning would stop at this failure with the message:
TASK [networking : set net.ipv6.conf.all.forwarding to 1] **********************
fatal: [10.121.0.77]: FAILED! => {"changed": false, "msg": "Failed to reload sysctl: sysctl: cannot stat /proc/sys/net/ipv6/conf/all/forwarding: No such file or directory\n"}
Solution
The fix had been backported to older versions of KIB wherein it checks if the file is present before attempting to modify [1]. Make sure you have the correct and latest version of KIB for your deployment as stated in the Konvoy Image Builder documentation [2].
If you are experiencing this and would need manual intervention, you can perform the following steps after you have created your bootstrap cluster:
docker pull mesosphere/konvoy-image-builder:v1.24.3
kind load docker-image mesosphere/konvoy-image-builder:v1.24.3 -n konvoy-capi-bootstrapper
kubectl patch deployment cappp-controller-manager -n cappp-system --type "json" -p '[{"op":"add","path":"/spec/template/spec/containers/0/args/-","value": "--konvoy-image-builder-version=v1.24.3"}]'
Note that you should use the latest minor version that corresponds with your DKP installation as stated in the documentation [2].