yubico otp / pam / openvpn
Quick notes on setting up pam_yubico.so with OpenVPN. Add to OpenVPN server config: plugin /usr/lib/x86_64-linux-gnu/openvpn/plugins/openvpn-plugin-auth-pam.so openvpn # Use a generated token instead of user/password for up # to 16 hours, so you'll need to re-enter your otp daily. auth-gen-token 57600 Sign up at https://upgrade.yubico.com/getapikey/. It's really quick. Store client_id and secret (or id and key respectively). You'll need them in the config below. Get PAM module: # apt-get install --no-install-recommends libpam-yubico Create /etc/pam.
proxmox / virtio-blk / disk by-id
Why does the virtio-blk /dev/vda block device not show up in /dev/disk/by-id? Yesterday, I wrote about how Proxmox VE attaches scsi0 and virtio0 block devices differently. That is the starting point for todays question: how come do I get /dev/sda in /dev/disk/by-id while /dev/vda is nowhere to be found? This question is relevant if you're used to referencing disks through /dev/disk/by-id (for example when setting up ZFS, using the device identifiers).
proxmox / alter default create vm parameters
The Proxmox Virtual Environment has defaults when creating a new VM, but it has no option to change those defaults. Here's a quick example of hacking in some defaults. Why? (Changing SCSI controller does not change existing disks) In the next post I wanted to talk about /dev/disk/by-id and why disks that use the VirtIO SCSI controller do not show up there. A confusing matter in this situation was that creating a VM disk using a different SCSI controller and then switching does not change the storage driver for the existing disks completely!
openvpn / hardened fox-it openvpn-nl
Today, we will be evaluating OpenVPN-NL — “[a] hardened version of OpenVPN that includes as many of the security measures required to operate in a classified environment as possible — and whether we can use it as a drop-in replacement for regular OpenVPN. While OpenVPN allows many insecure configurations, such as turning off encryption, or the use of outdated cryptographic functions in security critical places, the goal of OpenVPN-NL — a fork created and maintained by Fox-IT — is to strip insecure configuration and verify that the distributed version is uncompromised.
postgresql inside kubernetes / no space left on device
Running PostgreSQL inside Kubernetes? Getting occasional "No space left on device" errors? Know that 64MB is not enough for everyone. With the advent of more services running inside Kubernetes, we're now running into new issues and complexities specific to the containerization. For instance, to solve the problem of regular file backups of distributed filesystems, we've resorted to using rsync wrapped inside a pod (or sidecar). And now for containerized PostgreSQL, we're running into an artificial memory limit that needs fixing.
chromium snap / wrong fonts
So, since a couple of weeks my snap-installed Chromium browser on Ubuntu Focal started acting up: suddenly it chooses the wrong fonts on some web pages. The chosen fonts are from the ~/.local/share/fonts/ directory. Look! That's not the correct font. And it's even more apparent that the font is off when seeing the source view. Bah. That's not even a monospaced font. A fix that appeared to work — but unfortunately only temporarily — involves temporarily moving the custom local fonts out of the way and then flushing the font cache:
stale apparmor config / mysql refuses to start
So, recently we had an issue with a MariaDB server that refused to start. Or, actually, it would start, but before long, SystemD would kill it. But why? # systemctl start mariadb.service Job for mariadb.service failed because a timeout was exceeded. See "systemctl status mariadb.service" and "journalctl -xe" for details. After 90 seconds, it would be killed. systemctl status mariadb.service shows the immediate cause: # systemctl status mariadb.service ... systemd: mariadb.
zfs / zvol / partition does not show up
On our Proxmox virtual machine I had to go into a volume to quickly fix an IP address. The volume exists on the VM host, so surely mounting is easy. Right? I checked in /dev/zvol/pve2-pool/ where I found the disk: # ls /dev/zvol/pve2-pool/vm-125-virtio0* total 0 lrwxrwxrwx 1 root root 10 Dec 29 15:55 vm-125-virtio0 -> ../../zd48 Good, there's a disk: # fdisk -l /dev/zd48 Disk /dev/zd48: 50 GiB, 53687091200 bytes, 104857600 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 8192 bytes I/O size (minimum/optimal): 8192 bytes / 8192 bytes Disklabel type: dos Disk identifier: 0x000aec27 Device Boot Start End Sectors Size Id Type /dev/zd48p1 * 2048 97656831 97654784 46.
(I’m sorry, this time the recap is in Dutch instead of English. If you’re reading this, you’re probably Dutch anyway, so it won’t be a problem.) COVID-jaar 2020 is een vreemd jaar geweest, maar voor OSSO was het ook een goed jaar. Waar 2020 nog in mineur begon, omdat we eind 2019 nog een dierbare collega verloren aan een emigratiewens naar het land van de kangoeroes, hebben we in 2020 twee nieuwe collega’s mogen verwelkomen.
zfs destroy / dataset is busy
Just now, I tried to remove a ZFS dataset, and it reported dataset is busy for no apparent reason. # zfs list -r data NAME USED AVAIL REFER MOUNTPOINT data 3.12T 405G 251M /data data/kubernetes-logging 2.08T 405G 2.08T /data/kubernetes/logging data/rook-config 36.5M 405G 36.5M /data/rook-config data/rook-data 1.03T 708G 753G - # zfs destroy data/kubernetes-logging cannot destroy 'data/kubernetes-logging': dataset is busy The usual suspects were checked: The dataset was not mounted (cat /proc/mounts | grep kubernetes).