Snap install fails on long hostnames

[mxm-tr]

Summary

The snap install of microk8s fails when generating certificates on long hostnames, it fails with the following error message:

+ chown 0:0 /var/snap/microk8s/6541/certs/kubelet.key
+ chmod 0600 /var/snap/microk8s/6541/certs/kubelet.key
+ /snap/microk8s/6541/usr/bin/openssl req -new -sha256 -subj /CN=system:node:test-microk8s-snap-with-very-very-very-very-very-long-hostname/O=system:nodes -key /var/snap/microk8s/6541/certs/kubelet.key -addext 'subjectAltName = DNS:test-microk8s-snap-with-very-very-very-very-very-long-hostname, IP:57.128.88.67, IP:2001:41d0:304:500::323'
problems making Certificate Request
140456057689792:error:0D07A097:asn1 encoding routines:ASN1_mbstring_ncopy:string too long:../crypto/asn1/a_mbstr.c:107:maxsize=64

What Should Happen Instead?

We should be able to install the snap on servers with a hostname longer than 64, the value set for ub-common-name-length defined in rfc5280

Reproduction Steps

1. Configure a server with a long hostname (>64 chars)
2. Run snap install:

ubuntu@test-microk8s-snap-with-very-very-very-very-very-long-hostname:~$ sudo snap install microk8s --classic`

Introspection Report

NA: microk8s is not installed

Can you suggest a fix?

• Override the hostname of the server with a shorter version, and configure the alias in /etc/hosts?

• Or something else

Are you interested in contributing with a fix?

yes

[neoaggelos]

Hi @mxm-tr

MicroK8s uses the output of the hostname internally, so the only practical fix would be to ensure that the hostname does not exceed that limit.

One way to do it is to use hostnamectl set-hostname shorter-hostname

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.