RHV

On AdminPortal, you see that the VM status becomes unknown with a black question mark and all operations become grey and no operation can be done on this VM as follows: This post will show you how to reset state of vm in the engine databse and run the VM again. 1. Follow the below […]

Backup Use the engine-backup command to create a backup. The usage and mandatory arguments with the command are listed below: 1. –mode=MODE where MODE -> for collecting backup it should be set to “backup” 2. –scope=SCOPE where SCOPE -> can be set to “all” or “files” or “db” or “dwhdb” if set to “all” everything […]

This post will explain some practical psql commands and describe how to run the PostgreSQL queries from the command line to get useful information from the engine database. Connect To The ‘Postgres’ Database From The Command Line To connect to the ‘Postgres’ database: # su – postgres Last login: Thu Apr 30 20:25:36 AEST 2020 […]

This post will tell the process of shutdown a VM when you press the ‘shutdown’ button from AdminPortal. Here is the detailed process of a VM shutdown: 1. On AdminPortal, click ‘shutdown’ button on a VM. 2. RHV engine sends the “PoweringDown” to vdsm. 3. vdsm talks with libvirt to release VM resources. The below […]

Logical volume extension is used to provide additional storage and facilitate the continued operations of the virtual machine. This article will tell the process of Qcow2 type logical volume extension with thin provision allocation. Here is the process of LV extension: 1. When the virtual disk image is stored on storage with Qcow2 format, Qemu […]

Qemu Guest Agent has many features like shutdown/restart VM guest and also provides information about the VM guest. You can see basic information which is provided by qemu-guest-agent in Adminportal ( Compute –> Virtual Machines –> Click the VM –> Guest Info ). This post will list the essential features that Qemu Guest Agent provides. […]

Libvirt uses the Qemu guest agent running inside a VM. This post will elaborate on how the Qemu agent act as a communication channel between KVM host and the guest. Communication Protocol The communication protocol used to fetch information of the VM OS or issue commands to the Guest OS is Qemu Machine Protocol(QMP). QMP […]

In RHV 4.3.6, there are three migration policies: Minimal downtime, Suspend workload if needed and Post-copy migration. This post will explain them in details. Live VM migration mainly involves the transfer of VM’s CPU, memory, and I/O state from the source KVM host to the destination KVM host. With regards to “Minimal downtime” and “Suspend […]

This post will illustrate the fencing policy for a cluster. Enable fencing By default, fencing is enabled on the cluster. However, it can be disabled if it is required. If this option is disabled, that means it will complete disabling fencing for hosts in the cluster. This is usable in the situation when there are […]

This post provides a comprehensive list of all configuration options available in vdsm.conf for vdsm. The file vdsm.conf.sample includes a commented list of all available options in vdsm.conf. This is provided by vdsm package. You can find it at: /usr/share/doc/vdsm-4.30.33/vdsm.conf.sample For example, check the configurable VDSM tunables for volumes: $ less /usr/share/doc/vdsm-4.30.33/vdsm.conf.sample |grep -i -C2 […]