OpenStack Request Flow - McMaster...
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Engineering Services for OpenStack OpenStack Request Flow TM BUILT FOR openstack TM CLOUD SOFTWARE
Transcript of OpenStack Request Flow - McMaster...
Engineering Services for OpenStack
OpenStack Request Flow
TM
B U I LT F O R
openstack TM
CLOUD SOFTWARE
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
1. Multiple compute nodes in OpenStack cluster 2. Compute node is installed on hypervisor host 3. All compute nodes must be network connected with controller node 4. a component receive a message from queue and then retrieve detail information from database
Weina
附注
1. One controller node in OpenStack cluster. 2. queue and database can be accessed by all controller and compute nodes 3. queue is a message queue (central hub) for communication between components 4. queue is based on asynchronous communication 5. database stores build-time and run-time state of cloud
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
1. keystone provides identity service 2. supports token-based authentication 3. supports user-service based authorization 4. can integrate with existing authentication system
Weina
附注
1. In order to obtain an API token, the dashboard or command line need to request it from keystone (cloud provider's authentication server) 2. The client has to provide the URL of their authentication server as well as user name and password
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
nova API is implemented as REST API
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
The response contains the token itself (the id key in the token dictionary), the token expiry date/time and the catalog of services you can talk to that accept the token.
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
For the case of retrieving instances, nova-api get instances from database and return to client directly.
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
nova-scheduler is to make a decision on where a new instance should be created according to pre-configured policy and instance requirements. After the host is decided, the host ID will be updated to the instance entry stored in database.
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Find an appropriate host via filtering and weigh5ng Update instance entry with host ID
Weina
附注
1. Filtering is to evaluate and determine which hosts are eligible for consideration when dispatching resource. 2. Weighting is to select the best proper host to create instance. 3. After passing filter scheduler, we get a list of candidate hosts. After passing weighting scheduler, we get just one host or nothing.
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
1. Only the host selected by nova-scheduler will get the request of "vm provision" 2. If no host is selected by nova-scheduler, "create instance" is failed and response is returned.
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
1. The message in queue just contains operation, instance and host ID. The detailed information is stored in database. 2. Openstack supports multiple types of hypervisor. nova-compute will call different kind of API for different type of hypervisor. 3. The real operation, like creating/starting/stopping/deleting virtual machine is executed by hypervisor API.
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
1. Glance is for image registering, discovering and retrieving. Actual image is stored in Swift. 2. Besides of swift, image can be stored through NFS, HTTP, Amozan's S3.
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
reserve and allocation IP address for the instance.
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
1. vlans: compute node can be configured so that the virtual machine instances of different projects (organizations) are in different subnets, with each subnet having a different VLAN tag. 2. bridge config: the virtual instances can be configure with bridge network to allow two or more communication networks.
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Weina
附注
attach extra block level storage to new provisioned instance, which is optional
www.mirantis.com
B U I LT F O R
openstack TM
CLOUD SOFTWARE
Keystone
Poll for request instance status
Weina
附注
instance is ready, update the status of instance entry stored in database
Engineering Services for OpenStack
