Install and configure a compute node for Red Hat Enterprise Linux and CentOS¶
This section describes how to install and configure the Compute service on a compute node. The service supports several hypervisors to deploy instances or virtual machines (VMs). For simplicity, this configuration uses the Quick EMUlator (QEMU) hypervisor with the 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 section. Each additional compute node requires a unique IP address.
Install and configure components¶
Note
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.
Install the packages:
# yum install openstack-nova-compute
Edit the
/etc/nova/nova.conf
file and complete the following actions:In the
[DEFAULT]
section, enable only the compute and metadata APIs:[DEFAULT] # ... enabled_apis = osapi_compute,metadata
In the
[DEFAULT]
section, configureRabbitMQ
message queue access:[DEFAULT] # ... transport_url = rabbit://openstack:RABBIT_PASS@controller
Replace
RABBIT_PASS
with the password you chose for theopenstack
account inRabbitMQ
.In the
[api]
and[keystone_authtoken]
sections, configure Identity service access:[api] # ... auth_strategy = keystone [keystone_authtoken] # ... www_authenticate_uri = http://controller:5000/ auth_url = http://controller:5000/ 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 thenova
user in the Identity service.Note
Comment out or remove any other options in the
[keystone_authtoken]
section.In the
[service_user]
section, configure service user tokens:[service_user] send_service_user_token = true auth_url = https://controller/identity auth_strategy = keystone auth_type = password project_domain_name = Default project_name = service user_domain_name = Default username = nova password = NOVA_PASS
Replace
NOVA_PASS
with the password you chose for thenova
user in the Identity service.In the
[DEFAULT]
section, configure themy_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.Configure the
[neutron]
section of /etc/nova/nova.conf. Refer to the Networking service install guide for more details.In the
[vnc]
section, enable and configure remote console access:[vnc] # ... enabled = true server_listen = 0.0.0.0 server_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 replacecontroller
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
In the
[oslo_concurrency]
section, configure the lock path:[oslo_concurrency] # ... lock_path = /var/lib/nova/tmp
In the
[placement]
section, configure the Placement API:[placement] # ... region_name = RegionOne project_domain_name = Default project_name = service auth_type = password user_domain_name = Default auth_url = http://controller:5000/v3 username = placement password = PLACEMENT_PASS
Replace
PLACEMENT_PASS
with the password you choose for theplacement
user in the Identity service. Comment out any other options in the[placement]
section.
Finalize installation¶
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 configurelibvirt
to use QEMU instead of KVM.Edit the
[libvirt]
section in the/etc/nova/nova.conf
file as follows:[libvirt] # ... virt_type = qemu
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
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.
Add the compute node to the cell database¶
Important
Run the following commands on the controller node.
Source the admin credentials to enable admin-only CLI commands, then confirm there are compute hosts in the database:
$ . admin-openrc $ openstack compute service list --service nova-compute +----+-------+--------------+------+-------+---------+----------------------------+ | ID | Host | Binary | Zone | State | Status | Updated At | +----+-------+--------------+------+-------+---------+----------------------------+ | 1 | node1 | nova-compute | nova | up | enabled | 2017-04-14T15:30:44.000000 | +----+-------+--------------+------+-------+---------+----------------------------+
Discover compute hosts:
# su -s /bin/sh -c "nova-manage cell_v2 discover_hosts --verbose" nova Found 2 cell mappings. Skipping cell0 since it does not contain hosts. Getting compute nodes from cell 'cell1': ad5a5985-a719-4567-98d8-8d148aaae4bc Found 1 computes in cell: ad5a5985-a719-4567-98d8-8d148aaae4bc Checking host mapping for compute host 'compute': fe58ddc1-1d65-4f87-9456-bc040dc106b3 Creating host mapping for compute host 'compute': fe58ddc1-1d65-4f87-9456-bc040dc106b3
Note
When you add new compute nodes, you must run
nova-manage cell_v2 discover_hosts
on the controller node to register those new compute nodes. Alternatively, you can set an appropriate interval in/etc/nova/nova.conf
:[scheduler] discover_hosts_in_cells_interval = 300