Category: Virtualization

How to connect to lxd container
lxd is an easy-to-use command-line interface for lxc (Linux container). In this blog post, I will show how to create an lxd container and connect to it.

To create an lxd container, run
```
lxc launch ubuntu:20.04 vm-1
```
Here vm-1 is the name of the container. ubuntu:20.04 tells lxc to create a new container with Ubuntu version 20.04.

To see the list of containers, you can use the command
```
lxc ls
```
This list IP address of the containers. If you have openssh-server installed and have a user name and password or SSH key set, you can login using the IP address.

If you just created the container, you don’t have any login, then you can use the command
```
lxc shell CONTAINER_NAME
```
Another way is to use lxc exec
```
lxc exec CONTAINER_NAME bash
```
Example
```
root@instance-20210627-0830:~# lxc exec vm-1 bash
root@vm-1:~#
```
If you have a login, then you can use the command
```
lxc console CONTAINER_NAME
```
This command will give you access to the console of the container.

See lxd
June 27, 2021
libvirt qemu unexpectedly closed the monitor Failed to create chardev
On CentOS 7 server, after installing KVM, i connected to server using Virt Manager. During VM creation, i get following error

libvirt.libvirtError: internal error: qemu unexpectedly closed the monitor: 2021-02-01T18:09:38.214356Z qemu-kvm: -chardev pty,id=charserial0: Failed to create chardev

To fix this, edit file
```
vi /etc/fstab
```
Find
```
devpts          /dev/pts        devpts  defaults	    	0       0
```
Replace with
```
devpts          /dev/pts        devpts  gid=5,mode=620	0       0
```
Reboot the server. After reboot, VM creation will work properly.

See KVM
February 1, 2021
Install Linux KVM on CentOS 7
Install kvm with
```
yum install -y qemu-kvm
```
Install libvirt, this is used to manage KVM virtual machines.
```
yum install -y libvirt-daemon-kvm libvirt-client
```
Enable libvirtd to start on boot
```
systemctl enable libvirtd
```
Start libvirtd
```
systemctl start libvirtd
```
To see status, run
```
systemctl status libvirtd
```
Install virt-install
```
yum install virt-install
```
Now you have Linux KVM installed. You can use virt-install or Virt Manager to create virtual machine.

When i create a Virtual Machine on CentOS 7, i get error reated to Failed to create chardev. If you get this error, click here for solution.

See KVM
February 1, 2021
Download OS Templates Virtualizor
To create a Virtal Machine (VPS) on Virtualizor, you need OS Template. You can use pre-made OS templates or make your own OS template. You can see list of pre-made OS templates provided by Virtualizor at

https://virtualizor.com/ostemplates

To download an OS Template, login to Virtualizor, from left side menu, click on
```
Media > Template Browser
```
Click the check boxe right side of the OS Template you need to download. Once you selected all OS Templates you need, scroll down, click “Save Settins” button.

See Virtualizor
January 27, 2021

Virtualizor Error No Gateway Found, Please assign a Gateway

On a Virtualizor server, when starting virtnetwork, i get the following error

[root@virtual2 ~]# service virtnetwork start
Error: No Gateway Found, Please assign a Gateway.
[root@virtual2 ~]#

This is because the network interface configuration doesn’t have GATEWAY defined. Find your network interface name with the command

ip link

Now check the configuration file for your network interface.

On this server, I had following configuration

[root@virtual2 ~]# cat  /etc/sysconfig/network-scripts/ifcfg-enp4s0 
### Hetzner Online GmbH installimage

DEVICE=enp4s0
ONBOOT=yes
BOOTPROTO=none
IPADDR=94.130.65.163
PREFIX=32
SCOPE="peer 94.130.65.129"
DEFROUTE=yes

IPV6INIT=yes
IPV6ADDR=2a01:4f8:10b:2f1c::2/64
IPV6_DEFAULTGW=fe80::1
IPV6_DEFROUTE=yes
IPV6_DEFAULTDEV=enp4s0
[root@virtual2 ~]#

You need to find the gateway used by your server, this can be done with the command

ip route

On this server, I have

[root@virtual2 ~]# ip route
default via 94.130.65.129 dev enp4s0 
94.130.65.129 dev enp4s0 proto kernel scope link src 94.130.65.163 
169.254.0.0/16 dev enp4s0 scope link metric 1002 
188.40.210.0/24 dev natbr3 proto kernel scope link src 188.40.210.32 
[root@virtual2 ~]#

From above, the gateway used by the server is 94.130.65.129.

Now edit the network interface configuration file

vi /etc/sysconfig/network-scripts/ifcfg-enp4s0

Find the line starting with

IPADDR=

Add below

GATEWAY=YOUR_GATEWAY_IP_HERE

In this case

GATEWAY=94.130.65.129

After this change restarting virtnetwork worked.

[root@virtual2 ~]# service virtnetwork start
Bringing up viifbr0 - OK
Waiting for 10 seconds...1...2...3...4...5...6...7...8...9...10
Internet connectivity check successful viifbr0 - OK
[root@virtual2 ~]#

See Virtualizor

January 21, 2021

Virtualizor error fetching interface information

When starting network in virtualizor server, i get following error

[root@virtual2 ~]# service virtnetwork start
eth0: error fetching interface information: Device not found
Error: No ip address found.
[root@virtual2 ~]#

To fix this error, find the network interface name with command

[root@virtual2 ~]# ip link
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp4s0:  mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
    link/ether 34:97:f6:00:11:1f brd ff:ff:ff:ff:ff:ff
3: natbr3:  mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:54:00:d9:3c:1c brd ff:ff:ff:ff:ff:ff
4: natbr3-nic:  mtu 1500 qdisc pfifo_fast master natbr3 state DOWN mode DEFAULT group default qlen 1000
    link/ether 52:54:00:d9:3c:1c brd ff:ff:ff:ff:ff:ff
[root@virtual2 ~]#

In this case, the name is enp4s0, we need to add this name in

Virtualizor Admin > Configuration > Master or Slave Settings > Network Settings > Network Interface

Virtualizor Network Interface

If you have master and slave severs, you need to select master or slave depending on where you get this error. If slave, there is a drop down, you need to select the correct server, then set the interface name.

See Virtualizor

January 21, 2021

Copy a file from host into LXD container
To copy file from host machine to LXD container run
```
lxc file push FILE_NAME CONTAINER_NAME/FOLDER/
```
Example
```
lxc file push ant-media-server-enterprise-2.2.1-20201029_2042.zip centos8/root/
```
To copy a file from the host machine to an lxd container, run
```
lxc file push FILE_NAME CONTAINER_NAME/path/to/folder/
```
To copy a file from LXD container to the local machine, run
```
lxc file pull first-vm/root/2.txt .
```
If you need to copy a folder and files inside, you can use option –recursive

See LXD
January 18, 2021
Virtualizor list all vms from command line
Virtualizor use libvirt to manage virtualmachines.

To list all virtual machines in a server, login to server using SSH as root.

run
```
virsh list
```
See Virtualizor
January 11, 2021
Auto Start KVM Virtual Machine
To auto start a KVM Virtual Machine on boot time, use command
```
virsh autostart VMNAME_HERE
```
To disable a VM from auto starting, run
```
virsh autostart VMNAME_HERE --disable
```
See KVM
December 15, 2020
Proxmox VE Access Console of LXC Container
To access console of a LXC container running under Proxmox, run
```
pct enter CT_ID_HERE
```
Example
```
pct enter 106
```
You don’t need to enter password, you will be logged in as user root.

See proxmox
November 14, 2020
Proxmox take snapshot of Virtual Machine
To take snapshot of virtual machine in proxmox, click on Virtual Machine, under Snapshots, clikc “Take Snapshot” button.

To create snapshot through command line, login to Proxmox server as user root, then run
```
qm snapshot VMID nameOfSnapShot
```
nameOfSnapShot = no space or special chars allowed. Sould start/end with alphabet (numbers should NOT be used at start/end).

See Proxmox
November 12, 2020

Proxmox pveperf

pveperf is a command line benchmarking tool in proxmox server.

root@server70:~# pveperf
CPU BOGOMIPS:      59199.84
REGEX/SECOND:      3672349
HD SIZE:           38.32 GB (/dev/md2)
BUFFERED READS:    79.99 MB/sec
AVERAGE SEEK TIME: 8.39 ms
FSYNCS/SECOND:     23.87
DNS EXT:           16.46 ms
DNS INT:           19.34 ms (hostonnet.com)
root@server70:~#

Here is benchmark on another server – Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz, 2 * 120 GB SSD ATA OCZ-VERTEX3

root@Proxmox-VE ~ # pveperf
CPU BOGOMIPS:      76805.76
REGEX/SECOND:      1126262
HD SIZE:           14.70 GB (/dev/mapper/vg0-root)
BUFFERED READS:    321.65 MB/sec
AVERAGE SEEK TIME: 0.20 ms
FSYNCS/SECOND:     1026.63
DNS EXT:           14.69 ms
root@Proxmox-VE ~ #

August 30, 2020