MicroK8s installation is failing when using launch configurations (1.27.2)

[f-bn]

Summary

Hello :)

I would like to setup a small MicroK8s cluster using the new "launch configurations" feature available since version 1.27. However, this doesn't work well when I want to automate the deployment using a config file delivered by Ansible before installing the snap.

Some informations about my setup :

• OS : Ubuntu 22.04 LTS
• Snap version : 2.59.4
• MicroK8s channel : 1.27/stable

Here is my config file :

root@mk8s01:~# cat /etc/microk8s.yaml
---
version: 0.1.0
persistentClusterToken: my-token # I use a 32 characters length token
extraKubeAPIServerArgs:
  --authorization-mode: RBAC,Node
extraKubeletArgs:
  --cluster-dns: 10.152.183.10
  --cluster-domain: cluster.local
addons:
- name: dns
- name: rbac
- name: metrics-server

Here is the error message I got :

root@mk8s01:~# snap install microk8s --classic --channel=1.27/stable
error: cannot perform the following tasks:
- Run install hook of "microk8s" snap if present (run hook "install":
-----
+ source /snap/microk8s/5372/actions/common/utils.sh
++ [[ /snap/microk8s/5372/meta/hooks/install == \/\s\n\a\p\/\m\i\c\r\o\k\8\s\/\5\3\7\2\/\a\c\t\i\o\n\s\/\c\o\m\m\o\n\/\u\t\i\l\s\.\s\h ]]
+ '[' -f /var/snap/microk8s/5372/var/lock/installed.lock ']'
++ /snap/microk8s/5372/bin/uname -m
+ ARCH=x86_64
+ export LD_LIBRARY_PATH=/snap/microk8s/5372/lib:/snap/microk8s/5372/usr/lib:/snap/microk8s/5372/lib/x86_64-linux-gnu:/snap/microk8s/5372/usr/lib/x86_64-linux-gnu
+ LD_LIBRARY_PATH=/snap/microk8s/5372/lib:/snap/microk8s/5372/usr/lib:/snap/microk8s/5372/lib/x86_64-linux-gnu:/snap/microk8s/5372/usr/lib/x86_64-linux-gnu
+ export PATH=/snap/microk8s/5372/usr/sbin:/snap/microk8s/5372/usr/bin:/snap/microk8s/5372/sbin:/snap/microk8s/5372/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/bin:/usr/local/bin
+ PATH=/snap/microk8s/5372/usr/sbin:/snap/microk8s/5372/usr/bin:/snap/microk8s/5372/sbin:/snap/microk8s/5372/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/bin:/usr/local/bin
+ export OPENSSL_CONF=/snap/microk8s/5372/etc/ssl/openssl.cnf
+ OPENSSL_CONF=/snap/microk8s/5372/etc/ssl/openssl.cnf
+ is_strict
+ cat /snap/microk8s/5372/meta/snap.yaml
+ grep -q strict
+ grep confinement
+ return 1
+ cat /proc/1/environ
+ grep container=lxc
+ cp -r --preserve=mode /snap/microk8s/5372/default-args /var/snap/microk8s/5372/args
+ mv /var/snap/microk8s/5372/args/certs.d/localhost__32000 /var/snap/microk8s/5372/args/certs.d/localhost:32000
+ '[' -e /var/lib/kubelet ']'
+ ln -s /var/snap/microk8s/common/var/lib/kubelet /var/lib/kubelet
+ echo '`/var/lib/kubelet` linked to /var/snap/microk8s/common'
`/var/lib/kubelet` linked to /var/snap/microk8s/common
+ mkdir /var/snap/microk8s/5372/certs
+ cp /snap/microk8s/5372/certs/csr.conf.template /var/snap/microk8s/5372/certs/csr.conf.template
+ mkdir -p /var/snap/microk8s/common/etc/launcher
+ for config_file in "/etc/microk8s.yaml" "$SNAP_USER_COMMON/.microk8s.yaml" "$SNAP_COMMON/.microk8s.yaml" "$SNAP/microk8s.default.yaml"
+ '[' -f /etc/microk8s.yaml ']'
+ echo 'Found config file /etc/microk8s.yaml, will use to initialize cluster.'
Found config file /etc/microk8s.yaml, will use to initialize cluster.
+ cp /etc/microk8s.yaml /var/snap/microk8s/common/etc/launcher/install.yaml
+ /snap/microk8s/5372/bin/cluster-agent init --pre-init --config-file /var/snap/microk8s/common/etc/launcher/install.yaml
Error: failed to apply configuration: failed to apply config part 0: failed to configure persistent token: failed to open /var/snap/microk8s/5372/credentials/persistent-cluster-tokens.txt: open /var/snap/microk8s/5372/credentials/persistent-cluster-tokens.txt: no such file or directory
Usage:
   init [flags]

Flags:
  -c, --config-file string   configuration file to read, or '-' to read from stdin
  -h, --help                 help for init
  -p, --pre-init             apply pre-init configuration, do not restart services or manage addons
-----)

It's working fine without the persistentClusterToken directive, so I guess this is related with a missing "copy" in /var/snap/microk8s/5372/credentials/persistent-cluster-tokens.txt file during the bootstrap.

Reproduction Steps

1. Create config file in /etc/microk8s.yaml or /root/snap/microk8s/common/.microk8s.yaml
2. snap install microk8s --classic --channel=1.27/stable

Introspection Report

Can't provide it since the installation is failing

Thanks :)

[ktsakalozos]

Hi @f-bn

Thank you for reporting this. The issue is with the persistentClusterToken line. We try to append the provided token but the token's file is not created yet.

As a temporary workaround while we patch and release the fix for the problem you can set the persistentClusterToken after the installation of the snap:

With:

$ sudo cat /etc/microk8s.yaml
---
version: 0.1.0
extraKubeAPIServerArgs:
  --authorization-mode: RBAC,Node
extraKubeletArgs:
  --cluster-dns: 10.152.183.10
  --cluster-domain: cluster.local
addons:
- name: dns
- name: rbac
- name: metrics-server

And:

$ cat ./microk8s-token.yaml 
---
version: 0.1.0
persistentClusterToken: 12345678901234567890123456789012

Do:

sudo snap install microk8s --classic
sudo microk8s status --wait-ready
sudo snap set microk8s config="$(cat microk8s-token.yaml)"

Apologies for the inconvenience.

[f-bn]

Hi @ktsakalozos

No problem, thanks for the quick workaround :)

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