How to monitor a KVM installation
The purpose of this article is to describe how OP5 Monitor can be used with the check_libvirt plugin for agentless monitoring of resource usage on a KVM installation. At the moment the plugin can monitor:
Host-specific parameters:
- Storage pool list
- Storage pool volume usage
- Running VM’s
VM-specific parameters:
- CPU Usage
- Memory Usage
- Disk I/O
- Network I/O
Prerequisites Copied
- Libvirt drivers need to be installed on both the op5 Monitor server and on the target KVM host(s).
- The plugin supports several transport protocols. In this guideline we will explain how to use the SSH and TLS features.
- If you want to use SSH, you need to set up key-based authentication for the monitor user on the op5 monitor server and the root user on the target KVM host (libvirt is usually running as root).
- If you want to use TLS as the communication protocol, then you will need to generate client and server certificates. Please follow the libvirt.org how-to for that. Be careful and follow all the steps in that how-to before you continue. Notice that the KVM host server is the server and the op5 Monitor server is the client for the TLS communication.
- All servers can be resolved in the DNS.
- Update op5 Monitor to get the latest plugin pack.
Check commands Copied
SSH as transport protocol Copied
If you use SSH, import the required check-commands in your configuration (‘Configure’ -> ‘Check Command Import -> check_libvirt_kvm*’). After the import you will have the following check commands:
Commands for guest VM’s Copied
| command_name | command_line |
|---|---|
| check_libvirt_kvm_guest_cpu | $USER1$/check_libvirt -H qemu+ssh://$ARG1$@$HOSTADDRESS$/system -N $ARG2$ -l CPU |
| check_libvirt_kvm_guest_disk_io | $USER1$/check_libvirt -H qemu+ssh://$ARG1$@$HOSTADDRESS$/system -N $ARG2$ -l IO |
| check_libvirt_kvm_guest_mem | $USER1$/check_libvirt -H qemu+ssh://$ARG1$@$HOSTADDRESS$/system -N $ARG2$ -l MEM |
| check_libvirt_kvm_guest_net_io | $USER1$/check_libvirt -H qemu+ssh://$ARG1$@$HOSTADDRESS$/system -N $ARG2$ -l NET |
Commands for KVM host server Copied
| command_name | command_line |
|---|---|
| check_libvirt_kvm_host_running | $USER1$/check_libvirt -H qemu+ssh://$ARG1$@$HOSTADDRESS$/system -l LIST |
| check_libvirt_kvm_host_storage_pool | $USER1$/check_libvirt -H qemu+ssh://$ARG1$@$HOSTADDRESS$/system -l POOL -s $ARG2$ |
| check_libvirt_kvm_host_volume | $USER1$/check_libvirt -H qemu+ssh://$ARG1$@$HOSTADDRESS$/system -l VOLUME -s $ARG2$/$ARG3$ |
| check_libvirt_kvm_host_volume_all | $USER1$/check_libvirt -H qemu+ssh://$ARG1$@$HOSTADDRESS$/system -l VOLUME |
Note: $ARG1$ macro in the command_line refer to the user you will use to connect to the KVM host server, in these case root, the $HOSTADDRESS$ refer to the KVM host and the $ARG2$ refer to the guest VM-name.
TLS as transport protocol Copied
If you prefer to use TLS, then you can add the above check command to your configuration; you only need to replace qemu+ssh with qemu+tls, (‘Configure’ -> ‘Commands’ -> ‘Add new command’ -> ‘Go’).
Adding the services Copied
Some service examples follow.
Add the required services as your needs, (‘Configure’ -> ‘Host: ’ -> ‘Go’ -> ‘Services for host ’ -> ‘Add new service’ -> ‘Go’):
Arguments are just examples; you need to adjust them to suit your environment.
Services for guest VM Copied
| service_description | check_command | check_command_args | Note |
|---|---|---|---|
| VM CPU Usage | check_libvirt_kvm_guest_cpu | root!sandbox-peer | * |
| VM Mem Usage | check_libvirt_kvm_guest_mem | root!sandbox-peer | * |
| VM Disk IO Usage | check_libvirt_kvm_guest_disk_io | root!sandbox-peer | * |
| VM Net IO Usage | check_libvirt_kvm_guest_net_io | root!sandbox-peer | * |
Services for KVM host server Copied
| service_description | check_command | check_command_args | Note |
|---|---|---|---|
| KVM storage pool usage | check_libvirt_kvm_host_storage_pool | root!default | * |
| KVM guest volume usage | check_libvirt_kvm_host_volume | root!win-sth1!default | * |
| KVM all volume usage | check_libvirt_kvm_host_volume_all | root | * |
| KVM running vm list | check_libvirt_kvm_host_running | root | * |
* Note: No warning or critical arguments are used in these examples. The plugin does however support thresholds.
This plugin and these check_commands have been successfully tested on CentOS/RHEL v.5.5 and 6.x with KVM 2.x.
More information about libvirt can be found at: www.libvirt.org