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What is openStack Compute Node?

asked 2014-10-02 07:49:04 -0500

murilo gravatar image

I am beginner in openStack. I've just created two Fedora 20 VM's.

In the first one I ran the openStack Controller, which started the web interface of openStack. And in the second I ran one openStack compute Node.

I don't know exactly what is a openStack compute node.

Thinking about VMware. I can relate the openStack Controller to the Vmware ESXI.

But I can't relate the compute node to anything.

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answered 2014-10-02 16:03:04 -0500

piyush_raman gravatar image

In simple and direct terms- Compute Node is actually a machine on which the VM's are actually deployed. As mentioned by @larsks, each compute node will run a hypervisor to deploy and run the VM. So each time that you launch an instance, all the associated computing resources ( vCPUs, RAM, HDD ( root file sidk only ) ) are actually consumed from the compute node ( aka physical machine associated hosting the VM ).

Openstack Controller node is the node which has all the Openstack Service Server's running. That is all the requests to-and-from the user happen at the controller node ONLY.

User <- -> Controller Node ( Openstack Services Servers ) <- -> Compute Node ( Local service agents running )

For e.g. user will give the request for deployment of a VM. This request is received by the controller node which further directs the compute node to execute the request.Compute node deploys the VM and informs the server. So the relation between a compute node and controller node is more of a client-server architecture EXCEPT that the users dont directly interact with the Compute Node.

On a controller node-

$ openstack-service status nova

openstack-nova-api (pid 27046) is running...

openstack-nova-cert (pid 27059) is running...

openstack-nova-conductor (pid 27086) is running...

openstack-nova-consoleauth (pid 27098) is running...

openstack-nova-novncproxy (pid 27110) is running...

openstack-nova-scheduler (pid 27123) is running...

On a compute node-

$ openstack-service status nova

openstack-nova-compute (pid 7274) is running...

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answered 2014-10-02 08:12:11 -0500

larsks gravatar image

The OpenStack "compute node" is the system that actually runs a hypervisor -- that is, this is where your virtual instances actually run. The "controller" runs the web interface, APIs, scheduler(s), etc that control your openstack environment.

So, your controller is like the "management interface" for VMware, and the compute node is more like a system running ESXi.

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answered 2014-10-02 08:16:41 -0500

dbaxps gravatar image

updated 2014-10-02 09:48:25 -0500

On F20 Compute Node :-

[root@icehouse1 ~(keystone_admin)]# ssh
Last login: Thu Oct  2 16:44:38 2014 from icehouse1.localdomain
[root@icehouse2 ~]# systemctl | grep openstack
openstack-ceilometer-compute.service                                                             loaded active running   OpenStack ceilometer compute agent
openstack-nova-compute.service                                                                   loaded active running   OpenStack Nova Compute Server
[root@icehouse2 ~]# systemctl | grep neutron
neutron-openvswitch-agent.service                                                                loaded active running   OpenStack Neutron Open vSwitch Agent

Compute Node is supposed to run your VMs, GRE or VXLAN (VLAN) tunnel is connecting Compute Node with your Controller ( in general Neutron Server)

Details of Real Two Node Cluster on F20 view here
View manual VM's Setup here

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Asked: 2014-10-02 07:49:04 -0500

Seen: 2,268 times

Last updated: Oct 02 '14