[OpenVZ/KVM/CentOS 7] No login prompt on boot

When converting CentOS 7 OpenVZ systems to KVM sometimes there is no login prompt after loading services. The machine is otherwise operating correctly. Here’s the fix to get the login prompt back: mv /etc/systemd/system/getty.target.wants/getty\@tty2.service /etc/systemd/system/getty.target.wants/getty\@tty1.service Afterwards the keyboard input may not work. Rebuilding the initial ramdisk will fix that: dracut -f

[RHEL 7/CentOS 7] Hanging Boot After Conversion to RAID1 (degraded RAID)

Quick fix… Rebuild the ramdisk. If you are using a rescue disk and are compiling for a different kernel version replace $(uname -r) with your kernel version: dracut –mdadmconf –fstab –add=”mdraid” –filesystems “xfs ext4 ext3 tempts devotes syses proc” –add-drivers=”raid1″ –force /boot/initramfs-$(uname -r) $(uname -r) Add the following to /etc/default/grub inside the quotes for the […]

[CentOS/Linux] WARN : [ipv6_add_route] ‘No route to host’ adding route ‘::/0′ via gateway ‘XXXX:YYYY:ZZZZ::1′ through device ”

When trying to add an IPv6 address to a server via the ifcfg-eth0 file resulted in the following error (redacted) upon restarting networking: RTNETLINK answers: Permission denied WARN     : [ipv6_add_route] ‘No route to host’ adding route ‘::/0′ via gateway ‘XXXX:YYYY:ZZZZ::1′ through device ” This was further confirmed by trying to add the IP […]

[Linux/NVME] Find serial number of NVME drive

Traditional methods of finding the serial number on a live Linux system do not work for nvme drives.  You can download the name-cli package from: https://github.com/linux-nvme/nvme-cli Once installed you will then have the “nvme” command and can find the serial number with the following command: nvme id-ctrl /dev/nvme0n1  

[Raspberry Pi 3/CentOS 7] ALSA lib confmisc.c:768:(parse_card) cannot find card ‘0’

ALSA lib confmisc.c:768:(parse_card) cannot find card ‘0’ ALSA lib conf.c:4241:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings ALSA lib conf.c:4241:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory ALSA lib confmisc.c:1251:(snd_func_refer) error evaluating name ALSA lib conf.c:4241:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory […]

[Linux] kernel:[Hardware Error]: MC4 Error (node 1): DRAM ECC error detected on the NB.

Sometimes on Linux systems you’ll get an error message similar to this: Message from syslogd@server at May  1 13:09:44 … kernel:[Hardware Error]: MC4 Error (node 1): DRAM ECC error detected on the NB. Message from syslogd@server at May  1 13:09:44 … kernel:[Hardware Error]: Error Status: Corrected error, no action required. Message from syslogd@server at May  […]

[RALink Driver/Linux] Driver/UTIL/include/os/rt_linux.h:278: error: expected specifier-qualifier-list before ‘kuid_t’

This error comes up on some linux machines (most notably updated CentOS/RHEL 6) when trying to compile the driver for RALink devices: Driver/UTIL/include/os/rt_linux.h:278: error: expected specifier-qualifier-list before ‘kuid_t’   This is due to this particular section of code in that file: #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,29) kuid_t                    […]