cinder-agent

cinder-agentThe client service for Cinder

by Akira Yoshiyama<[email protected]>

Current Nova and Cinder

VM host

nova-compute

VM VM

client-sidevolume driver

Storage

cinder-volumeserver-side

volume driver

cinder-apiR

PC

Sto

rage

Control

iSCSI, etc.


RE

ST

nova-api

RP

C

REST

Nova still has many client-side volume drivers.

VM host

nova-compute

VM VM

Storage


volume driver

cinder-apiR

PC

Sto

rage

Control

iSCSI, etc.


RE

ST

nova-api

RP

C

RESTComplex client-side

volume capability and many volume drivers

in nova-compute

nova-compute has to make many REST requests to attach/detach a volume.

VM host

nova-compute

VM VM

Storage


volume driver

cinder-apiR

PC

Sto

rage

Control

iSCSI, etc.


RE

ST

nova-api

RP

C

REST

complexREST requestsper attachment/

detachment

We have to use same version of Nova and Cinder.

VM host

nova-compute

VM VM

Storage

Oldcinder-volume

oldvolume driver

Oldcinder-api

RP

C

Storage

Control

iSCSI, etc.


RE

ST

nova-api

RP

C

RESTREST transactionfor attachment/

detachmentmay be changed.

Server/client-side volumedrivers may not keep

compatibilitybetween versions.

Other software has to implementvolume drivers to use Cinder service.

VM host

VM VM

Storage


volume driver

cinder-apiR

PC

Sto

rage

Co

ntro

l

iSCSI, etc.

OpenNebula,CloudStackand so on


RE

ST

Volume drivers innova-compute

can't be used withprograms written in

Java/C/Ruby/...

cinder-agent

● nova-compute should drop most of client-side volume capability and drivers.

● Take them to new client-side service of cinder.

VM host

cinder-agent


nova-compute

new!

Nova and Cinder with cinder-agent

VM host

cinder-agent

VM VM


Storage


volume driver

cinder-apiR

PC

Sto

rage

Co

ntro

l

iSCSI, etc.


RE

ST

nova-compute

RP

C

nova-api

RP

C

REST

nova-compute becomes simple.

VM host

cinder-agent

VM VM


Storage


volume driver

cinder-apiR

PC

Storage

Control

iSCSI, etc.


RE

ST

nova-compute

RP

C

nova-api

RP

C

REST

withoutclient-side volume

capability and drivers

REST Request to attach/detach a volume becomes simple.

VM host

cinder-agent

VM VM


Storage


volume driver

cinder-apiR

PC

Sto

rage

Co

ntro

l

iSCSI, etc.


RE

ST

nova-compute

RP

C

nova-api

RP

C

RESTOnly one REST request

to attach/detach a volume.

Complex transactionsbetween server/client-side

volume capabilityvia Cinder RPC

Nova can be used with newer/older version of Cinder.

VM host

Older cinder-agent

VM VM


Storage

Oldercinder-volume

server-sidevolume driver

Oldercinder-api

RP

C

Sto

rage

Co

ntro

l

iSCSI, etc.


RE

ST

nova-compute

RP

C

nova-api

RP

C

RESTSimple REST request to attach/detach a volume

is easy to keep its compatibility.

It's easy to use other software with Cinder.

VM host

cinder-agent

VM VM


Storage


volume driver

cinder-apiR

PC

Sto

rage

Co

ntro

l

iSCSI, etc.


RE

ST

RP

C

OpenNebula, CloudStackand so on

Other software just makesa simple REST request

to attach/detach a volume.

VM

VM host

cinder-agent

client-sidevolume driverclient-side

volume driver

Conclusion

Benefit of cinder-agent:– makes nova-compute simple and free for volume.

– makes REST requests to attach/detach a volume simple and easy to keep its compatibility.

– allows to use Nova with newer/older Cinder.

– makes other software easy to use Cinder.

Cinder becomes a stand-alone softwareby cinder-agent.

cinder-agent

Technology