Blog posts

Making Debian 9 (Stretch) configure GRUB to boot partitions with UUIDs

As per this bug:

The Debian 9 installer (up to v9.5 at least) does not always configure GRUB to find the boot partition using UUID, but leaves it pointing to /dev/sdb or whatever. This can be a problem if you change disks in the system. In particular, if you install from a USB stick and then remove it when the system reboots after the install this can change the disk /dev id. The result is a unbootable system. This can be a bit fiddly to fix (although the first thing that’s always worth trying is to reverse the changes you made and see if it boots, e.g. plug the install USB stick back in to the same usb slot).

Making static networking work in Ubuntu 18.04

Ubuntu 18.04 has switched to netplan for configuring the network interfaces. Netplan generates configurations for NetworkManager or systemd-networkd and effectively replaces ifupdown and the /etc/network/interfaces file.

In an install of Ubuntu Desktop, the default netplan configuration comes from /etc/netplan/01-network-manager-all.yaml which reads:

network:
  version: 2
  renderer: NetworkManager

This basically hands over all network control to NetworkManager. For a static setup we can change the configuration to:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp0s25:
      dhcp4: no
      addresses: [aaa.aaa.aaa.aaa/24]
      gateway4: bbb.bbb.bbb.bbb
      nameservers:
        search: [example.co.uk]
        addresses: [xxx.xxx.xxx.xxx,yyy.yyy.yyy.yyy,zzz.zzz.zzz.zzz]

Where enp0s25 is my network interface in this case, the address has a netmask of 255.255.255.0 and the search is the default dns search domain(s) (note this can be vital for getting automounting to work if your setup just uses machine names and assumes the domain is the same).

Making nis automounting work in Debian and Ubuntu (and BSD)

We have a problem that with recent versions of Ubuntu (16.04 and later) and Debian (8 and later) the normal way we set up automounting to mount our nis users home directories doesn’t work – apparently due to boot ordering issues. (It works fine with Red Hat derivatives). We accidentally found a solution when copying a BSD configuration…

We create a file in /etc/auto.master.d (gets read in by auto.master in the standard Debian/Ubuntu setup):

Invalid self-signed certificates in FreeNAS 11

Had a problem with several FreeNAS 11 systems – when trying to enable https for the web interface I couldn’t get a working certificate.

Generate internal CA.
Generate internal certificate.
Chrome complains the certificate is invalid and does not allow you to bypass it.
Delete certificate and CA, repeat, same problem.

After mucking about with using upper and lower case for the certificate CN names etc, eventually got things to work by generating a second certificate with the same CA. Which makes me think it might be this problem:

OneDrive for Business High CPU

Had an issue where OneDrive for Business (installed with Office 365) was constantly using one CPU core. None if the fixes involving the cache or resetting the client worked. The problem seems to have started with recent (possibly after Office 365 1712 8827.2148) updates. What did work was the solution in this thread:

https://social.technet.microsoft.com/Forums/en-US/c968088a-cabb-45bb-b171-0fe937ac1e1c/onedrive-for-business-uses-high-cpu-since-office-365-1712-88272148?forum=sharepointgeneral

Condensed version: Stop using the old client (groove.exe) and use the personal client instead, which now seems to work (at least, the latest Windows 10 version) with business accounts as well.