Posts

Runbooks newest first. By topic: Topics.

PiKVM: force 1080p (or any mode you want) by editing the EDID

rw; kvmd-edidconf –import-preset=v3.1080p-by-default –apply; ro; then reboot the host (or replug the HDMI) so it re-reads the EDID. On V4 Mini/Plus none of this is needed: they already do 1080p60.

Proxmox VE with Keycloak: OpenID Connect login (openid realm)

Confidential OIDC client in Keycloak, pveum realm add –type openid with preferred_username as the username claim, autocreate and ACLs. The old guides with /auth/realms/ and a ‘username’ mapper are no longer needed.

Proxmox VE without a subscription: no-subscription repositories on PVE 9 (deb822) and PVE 8

PVE 9 uses .sources (deb822) on trixie; PVE 8 uses .list on bookworm. Enterprise to Enabled: false, no-subscription on, same trick for Ceph and PBS. Copy/paste for both versions.

Proxmox: /usr/share/proxmox-ve/pve-apt-hook: not found when updating

The snippet /etc/apt/apt.conf.d/10pveapthook calls a script that no longer exists because proxmox-ve went away. Empty stub, apt install -f, apt install proxmox-ve. If you removed Proxmox on purpose, delete the snippet.

Proxmox: error: disk 'lvmid/…' not found at grub rescue

Old GRUB cannot parse LVM metadata once it wraps around the buffer. From the ISO: lvcreate -L 4M pve -n grubtemp and reboot. Then grub-efi-amd64 or grub-install so it does not come back.

Proxmox: VM is locked (snapshot-delete), cannot remove the snapshot

The delete stopped halfway because the disk snapshot no longer existed. qm unlock + qm delsnapshot –force removes it from the config; then clean whatever is left on the storage.

Proxmox: Windows is slow with CPU type host (md_clear and flush_l1d)

host exposes md_clear and flush_l1d; Windows sees them and enables mitigations that multiply RAM latency (100 ns → 2000 ns on old Xeons). x86-64-v2-AES or v3 do not expose them. qm set –cpu and stop/start.

Seafile: reclaim disk space with seaf-gc (the garbage collector)

Empty the library trash in the admin panel, stop Seafile (mandatory on CE), seaf-gc.sh –dry-run and then seaf-gc.sh. With the official Docker image, docker exec seafile /scripts/gc.sh does it all.

SSH: "no matching host key type found. Their offer: ssh-rsa" (and ssh-dss)

OpenSSH 8.8 turned off RSA/SHA-1 signatures and OpenSSH 10.0 deleted DSA. ssh-rsa takes two options; ssh-dss now only works from an older client.

Virtualized pfSense with VirtIO: no traffic until hardware checksum offload is disabled

With vtnet, FreeBSD drops packets whose checksum was never computed. Tick Disable hardware checksum offload and reboot the VM even though the GUI does not ask; until then no traffic flows.