Re: [Openstack] Documentation: Basic Concepts of OpenStack are lacking from official Getting Started PDF
Hi Alexey: Can you log these issues as separate bugs in the OpenStack Manuals launchpad project https://launchpad.net/openstack-manuals? That will make it easier to track and ensure that they get addressed. Take care, Lorin -- Lorin Hochstein Lead Architect - Cloud Services Nimbis Services, Inc. www.nimbisservices.com On Feb 20, 2012, at 12:16 AM, Alexey Eromenko wrote: Hello all, Anne: You were recommended contact by Todd Deshane (deshantm on IRC) about this issue. The problem: I'm new to OpenStack and while learning it, all of it's concepts seem wild. I have read the OpenStack Getting Started Guide PDF (from docs.openstack.org), but it doesn't explain the most basic concepts. Things like: 1. Why Object Storage (swift) vs. Network File System (NFS) = According to: notmyname notmyname technologov: the things that object storage in general (and swift specifically) provides is large scale, cheap, and durable storage notmyname technologov: object storage is all about relaxing some of the constraints of a posix-style system. for example, if you don't have to provide atomic operations (ie you can rely on eventual consistency), you can much more easily scale a storage system and not have a central point of failure Also: I have seen a video, that explains a bit about hashing searches, but very incomplete. Also what happens if new servers get added or removed ? Such concepts need to be added into the docs. Does Object Storage also stores files ? (seems yes) 2. Nova vs Images (glance) vs. Object Storage (swift) = Both (1) Nova-volume and (2) glance and (3) swift seem capable of storing VM hard disks. What's the conceptual difference between the three ? Possible Answer: notmyname technologov: nova-volume is for block storage attached to a VM. glance is to manage the VM images in a nova cluster and provide nice ways of storing them (a bridge to the storage, not the storage itself). swift is an object storage system that can be used by glance or on its own. swift isn't a filesystem, so it's not mountable like the devices managed with nova-volume Arguments Discussion: technologov come on... mountable term is a joke... nowadays you can mount GMail or Wikipedia... via FUSE technologov w.p. is not a Filesystem either :) notmyname ok, so you don't use swift like a traditional hard drive. the only access to it is API-based (and the API is http) notmyname that can be wrapped into a FUSE filesystem (but there are big tradeoffs in doing so--advantages too, of course) Once we can agree on the concepts, need to patch official docs. 3. Minimal OpenStack setup for new developers to get started is ? = Nova only ? Glance and Swift are optional modules, right? I'd be glad to help to improve docs, but I don't understand those concepts myself. More docs issues: = 4. Hierarchies terminology: How do you call Live-migration-domain in OpenStack lingo ? (group of hosts, where virtual machines can be live-migrated from one to the next) Are there any other types of domains / virtual machine groups / host machine groups in OpenStack concept / terminology ? 5. Cross-platform host OS support: Currently the heavy use of iptables mandates Linux host. This assumption is true if you only support KVM, Xen, LXC, OVZ, UML. With a possible future port of OpenStack to VirtualBox engine, this assumption is false. 5.a. Is iptables mandatory or optional ? 5.b. What other OpenStack features exist that may fail on FreeBSD hosts ? And on Windows hosts ? NOTE: I'm OK if OpenStack effort stays Linux-only, but this must be clearly documented, along with portability hints. 6. Also Dashboard GUI was not covered in getting started PDF, which seems important. 7. Security: Remote VM control is secured ? How ? Libvirtd ? (From my quick look it seems that nova connects to remote nova-compute, not to libvirtd.) 8. Which other important concepts might I miss ? -- -Alexey Eromenko Technologov, 20.02.2012. ___ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp smime.p7s Description: S/MIME cryptographic signature ___ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
Re: [Openstack] Documentation: Basic Concepts of OpenStack are lacking from official Getting Started PDF
Hi Alexey - Glad you were able to get some answers on IRC. Looks quite thorough, and not all these concepts are easily explained in the frozen/static written word. :) Sometimes videos and one-on-one discussions will serve you better. But of course we want to continuously improve docs so this feedback is welcome. More responses embedded below. On Sun, Feb 19, 2012 at 11:16 PM, Alexey Eromenko al4...@gmail.com wrote: Hello all, Anne: You were recommended contact by Todd Deshane (deshantm on IRC) about this issue. The problem: I'm new to OpenStack and while learning it, all of it's concepts seem wild. I have read the OpenStack Getting Started Guide PDF (from docs.openstack.org), but it doesn't explain the most basic concepts. For the Starter Guide, log your feedback on this project specifically: http://bugs.launchpad.net/openstackbook. Things like: 1. Why Object Storage (swift) vs. Network File System (NFS) = According to: notmyname notmyname technologov: the things that object storage in general (and swift specifically) provides is large scale, cheap, and durable storage notmyname technologov: object storage is all about relaxing some of the constraints of a posix-style system. for example, if you don't have to provide atomic operations (ie you can rely on eventual consistency), you can much more easily scale a storage system and not have a central point of failure Also: I have seen a video, that explains a bit about hashing searches, but very incomplete. Also what happens if new servers get added or removed ? Such concepts need to be added into the docs. A link to the video in the bug you log would be useful to the authors. Does Object Storage also stores files ? (seems yes) Yes. Lots of web devs use object storage to store and serve static images on websites. There are also archiving use cases. 2. Nova vs Images (glance) vs. Object Storage (swift) = Both (1) Nova-volume and (2) glance and (3) swift seem capable of storing VM hard disks. What's the conceptual difference between the three ? Possible Answer: notmyname technologov: nova-volume is for block storage attached to a VM. glance is to manage the VM images in a nova cluster and provide nice ways of storing them (a bridge to the storage, not the storage itself). swift is an object storage system that can be used by glance or on its own. swift isn't a filesystem, so it's not mountable like the devices managed with nova-volume Arguments Discussion: technologov come on... mountable term is a joke... nowadays you can mount GMail or Wikipedia... via FUSE technologov w.p. is not a Filesystem either :) notmyname ok, so you don't use swift like a traditional hard drive. the only access to it is API-based (and the API is http) notmyname that can be wrapped into a FUSE filesystem (but there are big tradeoffs in doing so--advantages too, of course) Once we can agree on the concepts, need to patch official docs. Would welcome patches. Conceptually speaking, you're coming at it from a point of transition in the history of the project. Nova-volume hasn't yet been replaced but several storage solutions want to offer plugins - there is no documentation about how to configure those yet, but it is a priority for Doc Day March 6th. [1] Nova-volume offers storage to virtual images running in nova. Glance is specifically for image storage. Swift is specifically for object storage. 3. Minimal OpenStack setup for new developers to get started is ? = Nova only ? Glance and Swift are optional modules, right? I'd be glad to help to improve docs, but I don't understand those concepts myself. From my view point, most people want a Dashboard. That said, I don't believe that OpenStack is all about Compute only, either. Them's fightin' words. Okay, not really, :) but believe me, storage is more important to some as a minimal install than computing power. You can't really make that decision of best minimal for people. Devstack.org is the best starting point for new Python devs, Trystack.org is the best starting point for new API devs. These are the suggested starting points. More docs issues: = 4. Hierarchies terminology: How do you call Live-migration-domain in OpenStack lingo ? (group of hosts, where virtual machines can be live-migrated from one to the next) Are there any other types of domains / virtual machine groups / host machine groups in OpenStack concept / terminology ? Not that I know of, but others may have a different opinion here. I'd like the list's input on this item specifically, please? 5. Cross-platform host OS support: Currently the heavy use of iptables mandates Linux host. This assumption is true if you only support KVM, Xen, LXC, OVZ, UML. With a possible future port of OpenStack to VirtualBox
Re: [Openstack] Documentation: Basic Concepts of OpenStack are lacking from official Getting Started PDF
I'll take a stab at some of these inline for a quick answer (But - do still file the bugs!) Thanks, Kiall On Mon, Feb 20, 2012 at 5:16 AM, Alexey Eromenko al4...@gmail.com wrote: Hello all, Anne: You were recommended contact by Todd Deshane (deshantm on IRC) about this issue. The problem: I'm new to OpenStack and while learning it, all of it's concepts seem wild. I have read the OpenStack Getting Started Guide PDF (from docs.openstack.org), but it doesn't explain the most basic concepts. Things like: 1. Why Object Storage (swift) vs. Network File System (NFS) = According to: notmyname notmyname technologov: the things that object storage in general (and swift specifically) provides is large scale, cheap, and durable storage notmyname technologov: object storage is all about relaxing some of the constraints of a posix-style system. for example, if you don't have to provide atomic operations (ie you can rely on eventual consistency), you can much more easily scale a storage system and not have a central point of failure Also: I have seen a video, that explains a bit about hashing searches, but very incomplete. Also what happens if new servers get added or removed ? Such concepts need to be added into the docs. Does Object Storage also stores files ? (seems yes) Object Storage can store files (it can store anything you like really..), but these files are only accessible over HTTP. 2. Nova vs Images (glance) vs. Object Storage (swift) = Both (1) Nova-volume and (2) glance and (3) swift seem capable of storing VM hard disks. What's the conceptual difference between the three ? nova-volume is akin to Amazon's EBS. Think of it as a USB drive you can attach to any of your running instances. (It's also possible to boot the instance off this drive, but that's another topic..) Swift (Object Storage) is akin to Amazon S3. Think of it as an web service API for storing and retrieving blobs of data (eg files, machine images etc). Glance is the service Nova asks for a machine image when you boot an instance. Glance can be configured to host the images itself (on the local disk of the glance serve), or it can be configured to ask Swift (Object Storage) for the image. Possible Answer: notmyname technologov: nova-volume is for block storage attached to a VM. glance is to manage the VM images in a nova cluster and provide nice ways of storing them (a bridge to the storage, not the storage itself). swift is an object storage system that can be used by glance or on its own. swift isn't a filesystem, so it's not mountable like the devices managed with nova-volume Arguments Discussion: technologov come on... mountable term is a joke... nowadays you can mount GMail or Wikipedia... via FUSE technologov w.p. is not a Filesystem either :) notmyname ok, so you don't use swift like a traditional hard drive. the only access to it is API-based (and the API is http) notmyname that can be wrapped into a FUSE filesystem (but there are big tradeoffs in doing so--advantages too, of course) FUSE in my opinion should receive nothing more than a cursory footnote in the documentation. Anything is mountable via FUSE, and any mention of FUSE or the ability to mount Swift is only going to cause confusion. Once we can agree on the concepts, need to patch official docs. 3. Minimal OpenStack setup for new developers to get started is ? = Nova only ? Glance and Swift are optional modules, right? There are 2 main OpenStack projects that can both be used in isolation, or together. Nova is a Compute service - It manages VMs. Swift is an Object Storage service - It manages blobs of data. A company wishing to build a CDN might deploy Swift, without Nova. A company wising to offer hosting services might deploy Nova, and * optionally*, Swift. Glance is required by Nova. I'd be glad to help to improve docs, but I don't understand those concepts myself. More docs issues: = 4. Hierarchies terminology: How do you call Live-migration-domain in OpenStack lingo ? (group of hosts, where virtual machines can be live-migrated from one to the next) Are there any other types of domains / virtual machine groups / host machine groups in OpenStack concept / terminology ? 5. Cross-platform host OS support: Currently the heavy use of iptables mandates Linux host. This assumption is true if you only support KVM, Xen, LXC, OVZ, UML. With a possible future port of OpenStack to VirtualBox engine, this assumption is false. All the iptables code is contained in an interchangeable class. You could write a driver for MS Windows Firewall if you wanted to. 5.a. Is iptables mandatory or optional ? Optional. You can swap it out for anything you wish, assuming a driver exists or you can write one for it..
