Storage driver

[SitoCH]

Hello, first of all, thank you for this repository: works great and straightforward. I just have a question about the default storage driver, why the default is devicemapper? I had some bad experiences with it on other OS and I've seen in your code that we can override it with overlay. Did you try overlay and you had problems? To override it I just have to put it in the config.yaml, right?

Thank you

Sito

[rhuss]

There is no particular reason for using devicemapper AFAIR, but it could be that I had some issues with overlay at the time (tbh, I don't remember ;-).

As you said, to override, just add a

docker:
  storage_driver: overlay2

to config.yml.

[SitoCH]

Perfect, I'll try that. One of the nodes had it's Docker volumes corrupted after an hard shutdown and I remember that I had the same issue on CentOS with the devicemapper driver. After I switched to overlay I never had these problems again so I'll try this also on the Raspberry's cluster.

[SitoCH]

I switched to overlay2 and it seems to be more reliable. The strange thing is that I had to change the option right in the mail.yml role because Ansible seems to ignore the values in the config.yml. The other thing that I had to modify was the kubeadm command, at the moment it doesn't officially supports overlay2 so I had to force it with --skip-preflight-checks:

command: kubeadm init --config /etc/kubernetes/kubeadm.yml --skip-preflight-checks
command: kubeadm join --token={{ kubeadm_token }} --skip-preflight-checks master:6443 

[SitoCH]

The problem is overlay2, using overlay everything works fine out of the box.

[robertpeteuil]

SitoCH - I had the same problem & resolution.

Based on the Docker website, it appears that Overlay2 is only supported on Debian Stretch (9). This can be seen on the drivers per Distro chart on this page

[rhuss]

@SitoCH @robertpeteuil So is the suggestion to switch to "overlay" in https://github.com/Project31/ansible-kubernetes-openshift-pi3/blob/master/roles/base/tasks/apt.yml#L44 ?

[SitoCH]

Yes, switching to overlay is the best choice. I'm using it successfully and even with a series of hard shutdowns everything kept running fine. Overlay2 isn't supported and when I tried devicemapper I had random corrupted volumes.

[rhuss]

Thanks for the info, just switched to overlay.