Why I cannot deploy charts in microk8s controller but I can do it in LXD

Question

I am learning Juju which I feel its amazing, but having problems as usual and very little around to find people who explain how it works. I hope any of you can guide me.

Question: deploying charts only works in LXD controller. In microk8s does not work. What can I do? Why is this happening?

Listing Controllers, there are two. A microk8s (the one already installed with Ubuntu 20.04) and the

LXD Hypervisor for localhost (that I dont know perfectly what it is)

Controller        Model                   User   Access     Cloud/Region         Models  Nodes    HA  Version
lxd-staging*      lxd-staging-model       admin  superuser  localhost/localhost       3      1  none  2.8.7
microk8s-staging  microk8s-staging-model  admin  superuser  microk8s/localhost        2      1     -  2.8.7

Listing models, one for each controller

administrator@master-ubuntu:~$ juju models -c lxd-staging
Controller: lxd-staging

Model               Cloud/Region         Type  Status     Machines  Access  Last connection
controller          localhost/localhost  lxd   available         1  admin   just now
default             localhost/localhost  lxd   available         0  admin   3 minutes ago
lxd-staging-model*  localhost/localhost  lxd   available         0  admin   31 seconds ago

administrator@master-ubuntu:~$ juju models -c microk8s-staging
Controller: microk8s-staging

Model                    Cloud/Region        Type        Status     Access  Last connection
controller               microk8s/localhost  kubernetes  available  admin   just now
microk8s-staging-model*  microk8s/localhost  kubernetes  available  admin   never connected

Deploying in LXD, works as expected.

administrator@master-ubuntu:~$ juju models
Controller: lxd-staging

Model               Cloud/Region         Type  Status     Machines  Access  Last connection
controller          localhost/localhost  lxd   available         1  admin   just now
default             localhost/localhost  lxd   available         0  admin   10 minutes ago
lxd-staging-model*  localhost/localhost  lxd   available         0  admin   8 minutes ago

administrator@master-ubuntu:~$ juju deploy mysql mysqldb
Located charm "cs:mysql-58".
Deploying charm "cs:mysql-58".

Deploying in microk8s, error.

administrator@master-ubuntu:~$ juju models
Controller: microk8s-staging

Model                    Cloud/Region        Type        Status     Access  Last connection
controller               microk8s/localhost  kubernetes  available  admin   just now
microk8s-staging-model*  microk8s/localhost  kubernetes  available  admin   never connected

administrator@master-ubuntu:~$ juju deploy mysql mysqldb
ERROR series "xenial" in a kubernetes model not valid

Answer 1

This occurs because the charm hasn't been written with Kubernetes in mind. In an ideal world, this shouldn't matter, but underlying subsystems do. There is an ongoing effort to correct this but for now you could maybe use MariaDB for Kubernetes.