Ubuntu 18.04 Bionic Beaver Linux enables Internet Protocol Version 6 (IPv6) by default. However, in certain situations, some users may find it desirable to disable IPv6 support or to re-enable it after it has been disabled. Disabling IPv6 support (Permanently) Disable ipv6 built-in kernel module. 1. Edit /etc/default/grub and append ipv6.disable=1 to GRUB_CMDLINE_LINUX and GRUB_CMDLINE_LINUX_DEFAULT like the following … [Read more...] about How to Disable IPv6 on Ubuntu 18.04 Bionic Beaver Linux
Archives for January 2021
How to Capture More Logs in /var/log/dmesg for CentOS/RHEL
Sometimes not all log messages in /var/log/dmesg can be captured after Linux OS/kernel boots up because of too many block devices attached to the server. This post illustrates another way to record all bootup log messages besides configuring the serial console. Basically kernel parameter "log_buf_len" can be configured to increase kernel log buffer size, Name: log_buf_len, Set the size of the kernel log buffer. Synopsis: log_buf_len= n [ KMG ] Description: Set the size of the … [Read more...] about How to Capture More Logs in /var/log/dmesg for CentOS/RHEL
Unable to Start RDMA Services on CentOS/RHEL 7
The Problem The RDMA service fails to start on CentOS/RHEL 7 machine. 'journalctl -r' command shows the below errors: Oct 11 11:01:15 geeklab systemd-modules-load: Failed to insert 'rds_rdma': Address family not supported by protocol Oct 11 11:01:15 geeklab systemd-modules-load: Failed to insert 'rds_rdma': Address family not supported by protocol Oct 11 11:01:15 geeklab systemd-modules-load: Failed to insert 'resilient_rdmaip': Address family not supported by protocol Oct 11 11:01:15 … [Read more...] about Unable to Start RDMA Services on CentOS/RHEL 7
How to rename a KVM VM with virsh
The syntax is to rename a KVM VM with virsh is as follows: # virsh domrename {domain} {new-name} Let's see an example of renaming a VM using virsh. 1. To rename VM from serverA to serverB, first shutdown the VM: # virsh shutdown serverA 2. Now to rename a VM, run: # virsh domrename serverA serverB Domain successfully renamed 3. To start the VM/domain: # virsh start serverB Rename KVM domain with virsh and XML 1. First get domain information in XML and save it to a new … [Read more...] about How to rename a KVM VM with virsh