Changing parameters in OpenStack configuration files
You can modify the following parameters in the OpenStack configuration files:
Parameter | Configuration file | Description | Value |
---|---|---|---|
scheduler_host_subset_size
|
/etc/kolla/nova-scheduler/nova.conf | Defines a number of compute nodes best suited for a new VM, one of which is randomly chosen by the scheduler. | Valid values are 1 or greater. Any value less than 1 is treated as 1. The higher the value, the less optimal the chosen node may be for a VM. The default value is 1. |
vxlan_udp_port
|
/etc/kolla/neutron-openvswitch-agent/ml2_conf.ini | Specifies the UDP port used for VXLAN tunnels. When changing the port, iptables rules are automatically configured for both the old and new ports. |
The default port is 4789. |
cpu_allocation_ratio
|
/etc/kolla/nova-compute/nova.conf |
Defines the virtual CPU to physical CPU allocation ratio. Changing CPU allocation ratio will not affect virtual CPUs already provisioned for virtual machines. |
Valid values are positive integer or float. The default value is 8.0. |
ram_allocation_ratio
|
/etc/kolla/nova-compute/nova.conf |
Defines the maximum reserved RAM to physical RAM allocation ratio. Changing RAM allocation ratio will not affect RAM already provisioned for virtual machines. |
Valid values are positive integer or float. The default value is 1.0. The maximum recommended value is 1.5. |
To change a compute parameter
Use the following command:
vinfra service compute set [--custom-param <service_name> <config_file> <section> <property> <value>] [--nova-compute-ram-allocation-ratio <value>] [--neutron-openvswitch-vxlan-port <value>] [--nova-scheduler-host-subset-size <value>] [--nova-compute-cpu-allocation-ratio <value>]
--custom-param <service_name> <config_file> <section> <property> <value>
-
Set custom parameters for OpenStack configuration files:
service_name
is the service name:nova-compute
orneutron-openvswitch-agent
config_file
specifies the service configuration file: nova.conf fornova-compute
or ml2_conf.ini forneutron-openvswitch-agent
section
specifies the section in the service configuration file where the parameter is defined:DEFAULT
in nova.conf oragent
in ml2_conf.iniproperty
is the parameter to be changed:ram_allocation_ratio
,scheduler_host_subset
, andcpu_allocation_ratio
in nova.conf;vxlan_udp_port
in ml2_conf.inivalue
is a new parameter value
--nova-compute-ram-allocation-ratio <value>
- Shortcut for
--custom-param nova-compute nova.conf DEFAULT ram_allocation_ratio <value>
--neutron-openvswitch-vxlan-port <value>
- Shortcut for
--custom-param neutron-openvswitch-agent ml2_conf.ini agent vxlan_udp_port <value>
--nova-scheduler-host-subset-size <value>
- Shortcut for
--custom-param nova-scheduler nova.conf DEFAULT scheduler_host_subset_size <value>
--nova-compute-cpu-allocation-ratio <value>
- Shortcut for
--custom-param nova-scheduler nova.conf DEFAULT cpu_allocation_ratio <value>
For example, to change cpu_allocation_ratio
and vxlan_udp_port
, run:
# vinfra service compute set --nova-compute-cpu-allocation-ratio 16.0 --neutron-openvswitch-vxlan-port 4787
To check that the custom parameters are successfully modified, run:
# vinfra service compute show +--------------+-------------------------------------------+ | Field | Value | +--------------+-------------------------------------------+ | <...> | <...> | | options | cpu_model: '' | | | custom_params: | | | - config_file: nova.conf | | | property: cpu_allocation_ratio | | | section: DEFAULT | | | service_name: nova-compute | | | value: 16.0 | | | - config_file: ml2_conf.ini | | | property: vxlan_udp_port | | | section: agent | | | service_name: neutron-openvswitch-agent | | | value: 4787 | | | notification_forwarding: disabled | | status | active | +--------------+-------------------------------------------+
The applied changes are consistent on all compute nodes and not overwritten after product updates and upgrades.
If you want to change the vCPU or RAM allocation ratio on a particular compute node, use this command with the --nodes
option. For example, to set cpu_allocation_ratio
to 16 on the node node001
, run:
# vinfra service compute set --nova-compute-cpu-allocation-ratio 16.0 --nodes node001