I recently setup Step CA in my homelab.

Proxmox UI allows setting up ACME only through Let’s Encrypt, but apparently you can setup other providers through the command line. So, this is how I went about it.

cp /root/root_CA.crt /usr/local/share/ca-certificates/homelab.crt
update-ca-certificates

# For Proxmox VE
pvenode acme account register self-hosted-ca foo@bar --directory https://web-server-1.lan.ketanvijayvargiya.com:12001/acme/acme/directory
# Or for Proxmox Backup Server
proxmox-backup-manager acme account register self-hosted-ca foo@bar --directory https://web-server-1.lan.ketanvijayvargiya.com:12001/acme/acme/directory