[500 OOPS: child died] is a permanent negative error reply, whereas [421 Timeout] is a temporary negative error reply. Downgrade vsftpd to a lower version to resolve this issue. Check vsftpd man pages for details on Transient Negative Completion reply and Permanent Negative Completion reply.
Author: Albert
How to copy an instance between two Openstack environments
Turn off the instance, and then using the nova image-create command, create a snapshot of the nova instance. openstack server list openstack server image create server2 --name server2-snapshot After the snapshot is created, it will be visible at a glance. Confirm snapshot in a glance with; openstack image list Download snapshot image openstack image save …
How to clear ceilometer in OpenStack
To clean up old ceilometer data in OpenStack, perform the following steps: First of all, stop the Telemetry service. systemctl stop openstack-ceilometer-collector openstack-ceilometer-notification openstack-gnocchi-metricd openstack-gnocchi-statsd openstack-aodh-evaluator openstack-aodh-listener openstack-aodh-notifier openstack-ceilometer-central Stop MongoDB service by entering the following on shell prompt. systemctl stop mongod Delete all files in /var/lib/mongodb and then restart MongoDB. cd /var/lib/mongodb rm -r …
Steps to install NVIDIA cuda driver in Linux server using YUM
Install kernel development headers kernel-devel. yum install kernel-devel Attach EPEL repository. Install Cuda driver. yum install cuda Now reboot server List installed GPU with nvidia-smi
How to install NVIDIA driver (proprietary) and uninstall Nouveau driver (open source) in Linux server
Start your Linux server in text mode. GUI mode will give an error while uninstalling the Nouveau driver or installing the NVIDIA driver. Remove Nouveau driver: Open /etc/default/grub in text editor [vi] and add the following option to GRUB_CMDLINE_LINUX modprobe.blacklist=nouveau On root shell, execute the following command to build the /boot/grub2/grub.cfg as follows: grub2-mkconfig -o …
How to Change hostname and IP address of Linux server without rebooting server
You can change option in third line in /etc/hosts file on Linux server without rebooting; /etc/hosts 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6 192.168.0.1 server.seimaxim.com seimaxim You can change all of the following options in /etc/sysconfig/network without reboot. /etc/sysconfig/network NETWORKING=yes HOSTNAME=server.seimaxim.com GATEWAY=192.168.0.1 Similarly options in /etc/sysconfig/network-scripts/ifcfg-eth0 can also be changed. /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0 …
Error while configuring IP in ifcfg-eth0 on Linux Server “RTNETLINK answers: network is unreachable”
This error may arise if the IP address and Gateway subnets are different. Make sure both IP address and Gateway have the same subnets. For reference, the ifcfg-eth0 configuration file is given below. TYPE="Ethernet" PROXY_METHOD="none" BROWSER_ONLY="no" BOOTPROTO="none" DEFROUTE="yes" IPV4_FAILURE_FATAL="no" IPV6INIT="yes" IPV6_AUTOCONF="yes" IPV6_DEFROUTE="yes" IPV6_FAILURE_FATAL="no" IPV6_ADDR_GEN_MODE="stable-privacy" NAME="eth0" UUID="3d9bd3c7-310c-4e46-a57c-5b3a99819f78" DEVICE="eth0" ONBOOT="yes" IPADDR="37.48.96.245" PREFIX="27" GATEWAY="37.48.96.254" DNS1="8.8.8.8" IPV6_PRIVACY="no" Remove route …
Rebuild initial ramdisk image in Linux server – How-To
You may need to rebuild initial ramdisk image after adding new hardware or software to server. Create backup as shown below; cp /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).bak.$(date +%m-%d-%H%M%S).img Use following command to rebuild initramfs dracut -f -v Make sure /boot/grub2/grub.cfg and /etc/grub2.cfg includes the menu to the new custom initramfs Rebuild grub.cfg; grub2-mkconfig -o /boot/efi/EFI/seimaxim/grub.cfg
LVM command vgs segfault with error ‘SIGBUS’ – How to resolve in CentOS 7
This is because of the following option in lvm.conf obtain_device_list_from_udev=0 Change from 0 to 1 to resolve the issue as mentioned below; obtain_device_list_from_udev=1 Rebuild initramfs.
Adding disk space from non-root-LVM to root-LVM
All users should be logged out of server except root. Fsck the filesystem. Reduce the non-root LVM by entering following command on root shell; lvresize --resizefs --size lvresize --resizefs --size -200G /dev/VolGroup00/LogVoL-USER After non-root LVM filesystem is reduced, increase the root-LVM filesystem using; lvresize --resizefs --size +500M /dev/VolGroup00/LogVol-ROOT Mount the filesystem.
How to convert LVM thin to LVM thick
There is no way to convert LVM thin to LVM thick. You can only transfer data from LVM thin to LVM thick. LVM thick is standard LVM.
Effect of restarting sshd daemon on current ssh sessions
After editing ssh configuration file /etc/ssh/sshd_config, there is no effect on current ssh connections. However, it is necessary to reload sshd after configuring /etc/ssh/sshd_config
How to boot server with older kernel and set it as default in CentOS and AlmaLinux
Identify the Linux Kernel installed on your server by executing following command in shell on file /boot/grub/grub.conf; grep '^[[:space:]]*kernel' /boot/grub/grub.conf To boot from old kernel which is 0 in /boot/grub/grub.conf, change the default value of old kernel to 1 in /boot/grub/grub.conf.
Kernel Panic – [kernel BUG at fs/namei.c:2536!] CentOS
This kernel panic error is caused by third party module VxFS. Further diagnosis with vmcore is required.
How to disable transparent huge pages [THP] in CentOS 8
On CentOS 8, In file editor open /etc/default/grub file, and add “transparent_hugepage=never” kernel parameter on the GRUB_CMDLINE_LINUX in options as shown below; GRUB_CMDLINE_LINUX="options transparent_hugepage=never" On command line execute grub2-mkconfig to build /boot/grub2/grub.cfg grub2-mkconfig -o /boot/grub2/grub.cfg [System with BIOS]grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg [System with UEFI] Reboot Server to apply changes. If THP is still not disabled, stop …
