Renewal of TLS certificates fails after upgrade from Debian 9 to Debian 10. Apparently the way certificates are used for SSH changes substantially – we can no longer SSH in. Another possible reason for the problem is that Debian 10 implements AppArmor. I assume that this is very similar to SELinux.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
