Disaster Recovery Strategies Using oVirt's new Storage Connection Management Features (DevConf.cz 2014)

1Allon Mureinik - oVirt 3.3 Storage DR Features

Disaster Recovery Strategies Using oVirt's new Storage Connection Management

Features

Allon MureinikTeam Lead, Cloud Storage, Red [email protected] / @mureinik

February 2014

2Allon Mureinik - oVirt 3.3 Storage DR Features

Agenda

● Storage concepts in oVirt● Storage Domain vs. Storage Server Connection

● oVirt 3.3's new APIs and capabilities● GUI● REST

● Putting it all together● DR me, please!

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Terminology

“Language is the means of getting an idea from my brain into yours without surgery”

- Mark Amidon

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Terminology

● Disk – A virtual disk used by a VM (or template)● VDSM terminology: Image

● Storage Domain – A large storage area monitored and managed by oVirt.

● Main usage: Provisioning disks● Supported storage types:

● File Storage: NFS, GlusterFS, POSIX, local FS● Block Storage: iSCSI, FCP

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So what’s a Storage Server Connection?

● The “physical” properties where the “virtual” Storage Domain can be found

● For file storage – a [mount] path● For iSCSI – target details – iqn, port, username,

password, etc.● For FCP – not available

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Terminology – a visual representation

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What’s the problem? (pre 3.3)

● Users aren’t aware of Storage Server Connections

● Users aren’t aware of the distinction between them and Storage Domains

● GUI:● One screen to add● Part of Storage Domains management

● REST:● No such entity● Queried and added via Storage Domain operations

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What’s the problem – GUI (NFS)

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The Problem – GUI (iSCSI)

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What’s the problem - REST

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What’s new in oVirt 3.3?

● Storage Server Connections are an entity● They can be queried, added and updated independently

of the Storage Domains● ... And as such can be edited

● Supported for NFS, POSIX, local FS and iSCSI● Both via the GUI and via REST● Some advanced operations only available in REST

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GUI – File based Storage Domains

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REST – The main collection

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REST – A property of a Storage Domain

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Is there a DR in the house?

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Approach 1 – Network trickery only

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Approach 1 – Network trickery only (2)

● When the DR site comes up, oVrit Engine sends the same connection details to the new hosts

● Luckily, the DR site has its own DNS server, and the old connection details just point to the replicated storage

● Extremely dangerous● Not flexible – requires similar (if not identical) hardware

configuration on both sites

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Approach 2 – Update the connection

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Approach 2 – Update the connection (2)

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Approach 2 – Update the connection (3)

● When switching over to the DR site, use the REST API to edit the connection details for all storage domains

● Applicable for NFS, POSIX and iSCSI● Redundant for FCP, of course

● Advantage: Relatively simple

● Disadvantage: another step in an already elaborate process

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Approach 3 – Redundant Connections

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Approach 3 – Redundant Connections (2)

● User REST API to add connection to all the storage servers, including the DR site, when the site is established

● Make sure, via network configuration, that each host can only access one storage server, so there aren’t any “collisions”

● Advantage: Preemptive, less steps when switching over to a DR site

● Disadvantage: Additional “useless” information in the production site

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Looking forward

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Looking forward (no commitment)

● Support for GlusterFS

● Connection redundancy for file domains

● ISCSI multipathing (oVirt 3.4)

● Integrations● E.g. Symantec Cluster Server

● Patches are welcome!

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Where now?

● oVirt homepage:● http://www.ovirt.org

● Feature page:● http://www.ovirt.org/Features/Manage_Storage_Connections

● Lists:● [email protected]

● Feedback:● http://devconf.cz/f/117