OpenStack —— 虚拟机的启动过程简述(八)
DashboardorCLIgets the user credential and does the REST call toKeystonefor authentication. Keystoneauthenticate the credentials and generate & send back auth-token which will be used for sending request to other Components through REST-call. DashboardorCLIconvert the new instance request specified in ‘launch instance’ or ‘nova-boot’ form to REST API request and send it tonova-api. nova-apireceive the request and sends the request for validation auth-token and access permission tokeystone. Keystonevalidates the token and sends updated auth headers with roles and permissions. nova-apiinteracts withnova-database. Creates initial db entry for new instance. nova-apisends therpc.callrequest tonova-schedulerexcepting to get updated instance entry with host ID specified. nova-schedulerpicks the request from thequeue. nova-schedulerinteracts withnova-databaseto find an appropriate host via filtering and weighing. Returns the updated instance entry with appropriate host ID after filtering and weighing. nova-schedulersends therpc.castrequest tonova-computefor ‘launching instance’ on appropriate host . nova-computepicks the request from thequeue. nova-computesend therpc.callrequest tonova-conductorto fetch the instance information such ashost ID and flavor( Ram , CPU ,Disk). nova-conductorpicks the request from thequeue. nova-conductorinteracts withnova-database. Return the instance information. nova-computepicks the instance information from thequeue. nova-computedoes the REST call by passing auth-token toglance-apito get the Image URI by Image ID from glance and upload image from image storage. glance-apivalidates the auth-token withkeystone. nova-computeget the image metadata. nova-computedoes the REST-call by passing auth-token toNetwork APIto allocate and configure the network such that instance gets the IP address. quantum-servervalidates theauth-token withkeystone. nova-computeget the network info. nova-computedoes the REST call by passingauth-token toVolume APIto attach volumes to instance. cinder-apivalidates the auth-token withkeystone. nova-computegets the block storage info. nova-computegenerates data for hypervisor driver and executes request on Hypervisor( vialibvirtorapi). 本文转自 wzlinux 51CTO博客，原文链接：http://blog.51cto.com/wzlinux/1964195，如需转载请自行联系原作者
