Differences

This shows you the differences between two versions of the page.

--- kvm [2019/02/09 09:39] – [Table] admin
+++ kvm [2021/02/14 09:36] (current) – [Edit networks] dani
@@ Line 1: / Line 1: @@
 ====== KVM manual ======
 ===== General =====
 This document shows and describes the most important commands for a KVM environment.
 ===== Host setup =====
 Before you can start with any virtual machine, you have to install the following packages first:
 <code bash>
 dnf -y install virt-install libvirt-daemon-kvm qemu-kvm libvirt-client qemu libvirt-daemon
 </code>
 It’s not a bad idea, to check, if your host system is virtualisation capable.
 <code bash>
@@ Line 68: / Line 56: @@
    LXC: Checking for cgroup 'blkio' controller mount-point                   : PASS
 </code>
 | **Note:**  | The warning about ''%%IOMMU%%'' can be ignored.  |
 ==== Test installation tree ====
 <code bash>
@@ Line 80: / Line 65: @@
 curl -O http://192.168.122.1/centos/7.4/os/
 </code>
 ===== Environment =====
 <code bash>
 virsh dumpxml <domain name> > <outputfile>.xml
 </code>
 <code bash>
 virsh create <outputfile>.xml
 </code>
 ===== Basic commands =====
+  * Completely delete a VM:<code bash>
-<code bash>
 virsh --connect qemu:///system destroy fedora27
 virsh --connect qemu:///system undefine fedora27
-</code>
+</code>| **Note:**  | This does not delete the data on the disk (Logical Volume or image)!  |
+  * Unordered List ItemEdit/configure the settings of a virtual machine (domain):<code bash>
-| **Note:**  | This does not delete the data on the disk (Logical Volume or image)!  |
-<code bash>
 virsh edit <domain name>
 </code>
+  * Unordered List ItemList all (also not started VM's):<code bash>
-<code bash>
 virsh --connect qemu:///system list --all
  Id    Name                           State
@@ Line 128: / Line 92: @@
  -     fedora27                       shut off
 </code>
+  * Start a console session for a VM:<code bash>
-<code bash>
 virsh --connect qemu:///system console centos7
+</code>
+  * Setup autostart (when booting the KVM server) for a VM:<code bash>
+virsh --connect qemu:///system autostart centos7
 </code>
+| **Note:**  | To remove autostart toggle, just run this command again!  |
 ===== Installation of VM’s =====
 If you want to add a second network interface, you should add it after the ''%%kickstart%%'' installation. If there are two or more interfaces configured, the installer (''%%dracut%%'') does not find the network based installation files. Here two example domains, one is a Fedora server and one is a CentOS server.
 ==== Fedora ====
 In this example the new virtual machine or domain (fedora27) will be installed using kickstart. Following features are given:
   * The disk is a logical volume (''%%/dev/mapper/sysvg-fedora27%%'')
@@ Line 152: / Line 113: @@
   * The VM has two network interfaces, one for internal guest/host comunication (the default network), and one for external connections via ''%%macvtap%%'' protocol
   * The installation tree lifes on a webserver ( http://dangiga.danlocal.net/fedora/27/os/ )
 <code bash>
@@ Line 165: / Line 124: @@
 virsh --connect qemu:///system console fedora27
 </code>
 | **Note:**  | In this example, we install a second network interface for direct connection to physical interface of the KVM host!  |
 | **Info:**  | If you want to configure a fix MAC address, use ''%%--mac=52:54:00:f3:30:0f%%'' switch in the ''%%--network%%'' context!  |
 ==== Centos ====
 In this example the new virtual machine or domain (centos7) will be installed using kickstart. Following features are given:
   * The disk is a logical volume (''%%/dev/mapper/sysvg-centos7%%'')
@@ Line 183: / Line 136: @@
   * The VM has one network interfaces for internal guest/host comunication (the default network) only
   * The installation tree lifes on a webserver ( http://dangiga.danlocal.net/centos/7.4/os/ )
 <code bash>
@@ Line 195: / Line 146: @@
 virsh --connect qemu:///system console centos7
 </code>
 ===== Networking =====
+  * List all networks:<code bash>
-<code bash>
 virsh net-list --all
 </code>
+  * Attach a network interface to a virtual machine (domain):<code bash>
-<code bash>
 virsh attach-interface --domain <vm name> --type bridge --source virbr0 --model virtio --config --live
-</code>
+</code><code bash>
-<code bash>
 virsh attach-interface --domain <vm name> --type direct --source enp0s31f6 --model virtio --config --live
 </code>
+| **Note:**  | The ''%%--live%%'' switch only works, if the VM is started!  |
-||The ''%%--live%%'' switch only works, if the VM is started!|
+  * Unordered List ItemIf you want to figure out the IP addresss of one or more VM’s, you can use the following command executed on the KVM host:<code bash>
-If you want to figure out the IP addresss of one or more VM’s, you can use the following command executed on the KVM host.
-<code bash>
 vm=fedora27
 for mac in `virsh domiflist $vm |grep -o -E "([0-9a-f]{2}:){5}([0-9a-f]{2})"` ; do
@@ Line 233: / Line 165: @@
 done
 </code>
 ==== Edit networks ====
-The ''%%virsh%%'' command also provides a editor for a network configuration. In this example the default network is edited.
+  * Unordered List ItemThe ''%%virsh%%'' command also provides a editor for a network configuration. In this example the default network is edited.<code bash>
-<code bash>
 virsh net-edit default
 </code>
+  * Show the network configuration of a network (here ''default'' net):<code bash>
-<code bash>
 virsh net-dumpxml default
-</code>
+</code>Output:<code bash>
-<code bash>
 <network>
   <name>default</name>
@@ Line 264: / Line 184: @@
   <bridge name='virbr0' stp='on' delay='0'/>
   <mac address='52:54:00:65:80:59'/>
-  <ip address='192.168.122.1' netmask='255.255.255.0'> (1)
+  <ip address='192.168.xxx.1' netmask='255.255.255.0'> (1)
     <dhcp>
-      <range start='192.168.122.40' end='192.168.122.254'/>
+      <range start='192.168.122.40' end='192.168.xxx.254'/>
-      <host mac='52:54:00:f3:30:0f' ip='192.168.122.10'/> (2)
+      <host mac='52:54:00:f3:30:0f' ip='192.168.xxx.xx'/> (2)
-      <host mac='52:54:00:f3:30:1f' ip='192.168.122.11'/>
+      <host mac='52:54:00:f3:30:1f' ip='192.168.xxx.xx'/>
-      <host mac='52:54:00:f3:30:2f' ip='192.168.122.12'/>
+      <host mac='52:54:00:f3:30:2f' ip='192.168.xxx.xx'/>
-      <host mac='52:54:00:f3:30:3f' ip='192.168.122.13'/>
-      <host mac='52:54:00:f3:30:4f' ip='192.168.122.14'/>
-      <host mac='52:54:00:f3:30:5f' ip='192.168.122.15'/>
-      <host mac='52:54:00:f3:30:6f' ip='192.168.122.16'/>
-      <host mac='52:54:00:43:56:0e' ip='192.168.122.17'/>
-      <host mac='52:54:00:43:56:1e' ip='192.168.122.18'/>
-      <host mac='52:54:00:43:56:2e' ip='192.168.122.19'/>
-      <host mac='52:54:00:43:56:3e' ip='192.168.122.20'/>
-      <host mac='52:54:00:43:56:4e' ip='192.168.122.21'/>
-      <host mac='52:54:00:43:56:5e' ip='192.168.122.22'/>
-      <host mac='52:54:00:43:56:6e' ip='192.168.122.23'/>
-      <host mac='52:54:00:43:56:7e' ip='192.168.122.24'/>
     </dhcp>
   </ip>
 </network>
 </code>
 |**1**|Network IP and netmask                         |
 |**2**|Define a fix IP address for a given MAC address|
+  * Unordered List ItemAfter changing anything, you must activate the changed configuration, you have to reload the network:<code bash>
-After changing anything, you must activate the changed configuration, you have to reload the network:
-<code bash>
 virsh net-destroy default && virsh net-start default
 </code>
+  * Delete a vm (host) in a network (here ''default'' net):<code bash>
+virsh net-update default delete ip-dhcp-host "<host mac='52:54:00:f3:30:2f' name='hostname' ip='192.168.xxx.xxx'/>" --live --config
+</code>
-<code bash>
+  * Add a network configuration (host) live:<code bash>
-virsh net-update default delete ip-dhcp-host "<host mac='52:54:00:f3:30:2f' name='ds' ip='192.168.122.12'/>" --live --config
+virsh net-update default add ip-dhcp-host "<host mac='52:54:00:43:56:84' name='hostname' ip='192.168.xxx.xxx'/>" --live --config
 </code>
 ===== Harddisks =====
@@ Line 314: / Line 212: @@
 It’s also possible to add a disk to a running VM. The disk can be a disk image or a LVM volume. It’s possible to resize the disk, but, you have to reboot the client or relaod the kernel disk table (''%%partx%%'', only CentOS >=7).
+  * Add (persistent) a disk to a VM:<code bash>
-<code bash>
 virsh attach-disk ds --source /dev/sysvg/ds_test --target vdb --persistent
-</code>
+</code> \\ This adds a new disk to the ''%%ds%%'' VM as ''%%/dev/vdb%%'' persistently.
+| **Note:**  | The disk is a logical volume on the KVM host  |
-This adds a new disk to the ''%%ds%%'' VM as ''%%/dev/vdb%%'' persistently.
+==== Resize (LVM) disk ====
+  * First increase size of the LV on KVM host:<code bash>
+lvresize -G <size>G /dev/sysvg/<lv name>
+</code>
+  * Configure the size of that domain and disk using ''virsh'':<code bash>
+virsh blockresize <domain> /dev/sysvg/<lv name> --size <size>G
+</code> \\ Now, you can resize the disk on the domain (VM).
-||The disk is a logical volume on the KVM host|