Install and configure a compute node

Install and configure a compute node

This section describes how to install and configure the Compute service on a compute node. The service supports several hypervisors to deploy instances or VMs. For simplicity, this configuration uses the QEMU hypervisor with the KVM extension on compute nodes that support hardware acceleration for virtual machines. On legacy hardware, this configuration uses the generic QEMU hypervisor. You can follow these instructions with minor modifications to horizontally scale your environment with additional compute nodes.


This section assumes that you are following the instructions in this guide step-by-step to configure the first compute node. If you want to configure additional compute nodes, prepare them in a similar fashion to the first compute node in the example architectures section. Each additional compute node requires a unique IP address.

Install and configure components


Default configuration files vary by distribution. You might need to add these sections and options rather than modifying existing sections and options. Also, an ellipsis (...) in the configuration snippets indicates potential default configuration options that you should retain.

  1. Install the packages:

    # apt install nova-compute
  1. Edit the /etc/nova/nova.conf file and complete the following actions:

    • In the [DEFAULT] section, configure RabbitMQ message queue access:

      transport_url = rabbit://openstack:RABBIT_PASS@controller

      Replace RABBIT_PASS with the password you chose for the openstack account in RabbitMQ.

    • In the [DEFAULT] and [keystone_authtoken] sections, configure Identity service access:

      auth_strategy = keystone
      auth_uri = http://controller:5000
      auth_url = http://controller:35357
      memcached_servers = controller:11211
      auth_type = password
      project_domain_name = Default
      user_domain_name = Default
      project_name = service
      username = nova
      password = NOVA_PASS

      Replace NOVA_PASS with the password you chose for the nova user in the Identity service.


      Comment out or remove any other options in the [keystone_authtoken] section.

    • In the [DEFAULT] section, configure the my_ip option:


      Replace MANAGEMENT_INTERFACE_IP_ADDRESS with the IP address of the management network interface on your compute node, typically for the first node in the example architecture.

    • In the [DEFAULT] section, enable support for the Networking service:

      use_neutron = True
      firewall_driver = nova.virt.firewall.NoopFirewallDriver


      By default, Compute uses an internal firewall service. Since Networking includes a firewall service, you must disable the Compute firewall service by using the nova.virt.firewall.NoopFirewallDriver firewall driver.

    • In the [vnc] section, enable and configure remote console access:

      enabled = True
      vncserver_listen =
      vncserver_proxyclient_address = $my_ip
      novncproxy_base_url = http://controller:6080/vnc_auto.html

      The server component listens on all IP addresses and the proxy component only listens on the management interface IP address of the compute node. The base URL indicates the location where you can use a web browser to access remote consoles of instances on this compute node.


      If the web browser to access remote consoles resides on a host that cannot resolve the controller hostname, you must replace controller with the management interface IP address of the controller node.

    • In the [glance] section, configure the location of the Image service API:

      api_servers = http://controller:9292
    • In the [oslo_concurrency] section, configure the lock path:

      lock_path = /var/lib/nova/tmp
    • Due to a packaging bug, remove the log-dir option from the [DEFAULT] section.

Finalize installation

  1. Determine whether your compute node supports hardware acceleration for virtual machines:

    $ egrep -c '(vmx|svm)' /proc/cpuinfo

    If this command returns a value of one or greater, your compute node supports hardware acceleration which typically requires no additional configuration.

    If this command returns a value of zero, your compute node does not support hardware acceleration and you must configure libvirt to use QEMU instead of KVM.

    • Edit the [libvirt] section in the /etc/nova/nova-compute.conf file as follows:

      virt_type = qemu
  1. Restart the Compute service:

    # service nova-compute restart


If the nova-compute service fails to start, check /var/log/nova/nova-compute.log. The error message AMQP server on controller:5672 is unreachable likely indicates that the firewall on the controller node is preventing access to port 5672.

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