Resize additional disks in Siderolabs Talos Linux

"Talos will automatically resize the system disk partition(s) if the underlaying block size changes, but not user-managed disks. You would need to schedule a privileged pod with the host /dev/ mounted (kubectl debug node/<name> can do this for you) and use xfs_growfs to expand the filesystem to fit the block device.
Please note that Talos uses XFS, not EXT filesystems" (Source: https://taloscommunity.slack.com/archives/CG25RPZNE/p1718267363829179?thread_ts=1718242104.911039&cid=CG25RPZNE )

Starting from these instructions that I found on the Siderolabs Slack I put togheter these steps to grow the additional disk that I use on my nodes as space for Longhorn:

# create a namespace to kett things tidy
k create ns debug

# allow pod in created namespace to mount the host
k label ns debug pod-security.kubernetes.io/enforce=privileged

# create the debug pod
k debug node/nodename -it --image ubuntu --profile=sysadmin -n debug

# inside the pod
# update packet manager and install desired software
apt-get update && apt-get install xfsprogs parted

# lauch parted
parted

# inside parted I select the correct device
select /dev/sdb

# parted should warn that not all the space is used, type "Fix" and enter
Warning: Not all of the space available to /dev/sdb appears to be used, you can fix the GPT to use all of the space (an extra 10485760 blocks) or continue with the current setting?
Fix

# let's resize the partition
resizepart 1 100%

# exit from parted
quit

# exited parted
# now let's grow the file system
xfs_growfs -d /host/var/lib/longhorn

# it shoud be all ok, let's exit the pod
exit

The pod will continue running unless you delete it. Having all in a single namespace makes it easier to find what's left.