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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 <hypervisor> to deploy instances <instance> or VMs <virtual machine (VM)>. For simplicity, this configuration uses the QEMU <Quick EMUlator (QEMU)> hypervisor with the KVM <kernel-based VM (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.

Note

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 <overview-example-architectures> section. Each additional compute node requires a unique IP address.

Install and configure components

obs

  1. Install the packages:

    # zypper install openstack-nova-compute genisoimage qemu-kvm libvirt

rdo

  1. Install the packages:

    # yum install openstack-nova-compute

ubuntu or debian

  1. Install the packages:

    # apt install nova-compute

debian

Respond to prompts for debconf.

  1. Edit the /etc/nova/nova.conf file and complete the following actions:

    rdo or obs

    • In the [DEFAULT] section, enable only the compute and metadata APIs:

      [DEFAULT]
# ...
enabled_apis = osapi_compute,metadata

    obs

    • In the [DEFAULT] section, set the compute_driver:

      [DEFAULT]
# ...
compute_driver = libvirt.LibvirtDriver

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

      [DEFAULT]
# ...
transport_url = rabbit://openstack:RABBIT_PASS@controller

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

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

      [api]
# ...
auth_strategy = keystone

[keystone_authtoken]
# ...
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.

      Note

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

    debian

    • In the [DEFAULT] section, check that the my_ip option is correctly set (this value is handled by the config and postinst scripts of the nova-common package using debconf):

      [DEFAULT]
# ...
my_ip = MANAGEMENT_INTERFACE_IP_ADDRESS

      Replace MANAGEMENT_INTERFACE_IP_ADDRESS with the IP address of the management network interface on your compute node, typically 10.0.0.31 for the first node in the example architecture <overview-example-architectures>.

    obs or rdo or ubuntu

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

      [DEFAULT]
# ...
my_ip = MANAGEMENT_INTERFACE_IP_ADDRESS

      Replace MANAGEMENT_INTERFACE_IP_ADDRESS with the IP address of the management network interface on your compute node, typically 10.0.0.31 for the first node in the example architecture <overview-example-architectures>.

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

      [DEFAULT]
# ...
use_neutron = True
firewall_driver = nova.virt.firewall.NoopFirewallDriver

      Note

      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:

      [vnc]
# ...
enabled = True
vncserver_listen = 0.0.0.0
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.

      Note

      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:

      [glance]
# ...
api_servers = http://controller:9292

    obs

    • In the [oslo_concurrency] section, configure the lock path:

      [oslo_concurrency]
# ...
lock_path = /var/run/nova

    rdo or ubuntu

    • In the [oslo_concurrency] section, configure the lock path:

      [oslo_concurrency]
# ...
lock_path = /var/lib/nova/tmp

    ubuntu

    https://bugs.launchpad.net/ubuntu/+source/nova/+bug/1506667

    • Due to a packaging bug, remove the log_dir option from the [DEFAULT] section.

obs or debian

  1. Ensure the kernel module nbd is loaded.

    # modprobe nbd

  2. Ensure the module loads on every boot by adding nbd to the /etc/modules-load.d/nbd.conf file.

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.

    obs or rdo

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

      [libvirt]
# ...
virt_type = qemu

    ubuntu

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

      [libvirt]
# ...
virt_type = qemu

    debian

    • Replace the nova-compute-kvm package with nova-compute-qemu which automatically changes the /etc/nova/nova-compute.conf file and installs the necessary dependencies:

      # apt install nova-compute-qemu

obs or rdo

  1. Start the Compute service including its dependencies and configure them to start automatically when the system boots:

    # systemctl enable libvirtd.service openstack-nova-compute.service
# systemctl start libvirtd.service openstack-nova-compute.service

ubuntu or debian

  1. Restart the Compute service:

    # service nova-compute restart

Note

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. Configure the firewall to open port 5672 on the controller node and restart nova-compute service on the compute node.