Storing VMs with Cinder and Ceph RBD.pdf

Storing VMs with Cinder and

Ceph RBD

Growing With Hardware Appliances

First PB

•  Proprietary storage hardware

• Well-known storage vendor

$14 b’zillion

Second PB

•  Proprietary storage hardware

•  Same storage vendor

Another

$14 b’zillion

47

DC

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C++

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C++ X

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HUMAN [DEVELOPER]

!!

Hard Drives Are Tiny Record Players and They Fail Often jon_a_ross, Flickr / CC BY 2.0 71

72

D

55 times / day

= D

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x 1 MILLION

D D

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OPEN SOURCE

COMMUNITY-FOCUSED

SCALABLE

NO SINGLE POINT OF FAILURE

SOFTWARE BASED

SELF-MANAGING

philosophy design

79

RADOS A reliable, autonomous, distributed object store comprised of self-healing, self-managing,

intelligent storage nodes

LIBRADOS

A library allowing

apps to directly

access RADOS, with support for

C, C++, Java,

Python, Ruby,

and PHP

RBD A reliable and fully-

distributed block device, with a Linux

kernel client and a

QEMU/KVM driver

CEPH FS A POSIX-compliant

distributed file system, with a Linux

kernel client and

support for FUSE

RADOSGW A bucket-based REST

gateway, compatible with S3 and Swift

APP APP HOST/VM CLIENT

81

DISK

FS

DISK DISK

OSD

DISK DISK

OSD OSD OSD OSD

FS FS FS FS btrfs xfs

ext4

M M M

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M

M

M

HUMAN

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Monitors:

• Maintain cluster map

•  Provide consensus for distributed decision-making

• Must have an odd number

•  These do not serve stored objects to clients

M

OSDs: • One per disk (recommended)

•  At least three in a cluster

•  Serve stored objects to clients

•  Intelligently peer to perform replication tasks

•  Supports object classes

APP??

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APP

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DC

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DC

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APP

DC

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DC

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DC

DC

A-G

H-N

O-T

U-Z

F*

107

10 10 01 01 10 10 01 11 01 10

10 10 01 01 10 10 01 11 01 10

hash(object name) % num pg

CRUSH(pg, cluster state, rule set)

108

10 10 01 01 10 10 01 11 01 10

10 10 01 01 10 10 01 11 01 10

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CRUSH

•  Pseudo-random placement algorithm

•  Ensures even distribution

•  Repeatable, deterministic

•  Rule-based configuration

•  Replica count

•  Infrastructure topology

•  Weighting

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CLIENT

??

112

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CLIENT

??

111

84

RADOS A reliable, autonomous, distributed object store comprised of self-healing, self-managing,

intelligent storage nodes

LIBRADOS

A library allowing

apps to directly

access RADOS, with support for

C, C++, Java,

Python, Ruby,

and PHP

RBD A reliable and fully-

distributed block device, with a Linux

kernel client and a

QEMU/KVM driver

CEPH FS A POSIX-compliant

distributed file system, with a Linux

kernel client and

support for FUSE

RADOSGW A bucket-based REST

gateway, compatible with S3 and Swift

APP APP HOST/VM CLIENT

LIBRADOS

M

M

M

85

APP

native

L

LIBRADOS

•  Provides direct access to RADOS for applications

•  C, C++, Python, PHP, Java

• No HTTP overhead

87

RADOS A reliable, autonomous, distributed object store comprised of self-healing, self-managing,

intelligent storage nodes

LIBRADOS

A library allowing

apps to directly

access RADOS, with support for

C, C++, Java,

Python, Ruby,

and PHP

RBD A reliable and fully-

distributed block device, with a Linux

kernel client and a

QEMU/KVM driver

CEPH FS A POSIX-compliant

distributed file system, with a Linux

kernel client and

support for FUSE

RADOSGW A bucket-based REST

gateway, compatible with S3 and Swift

APP APP HOST/VM CLIENT

88

M

M

M

LIBRADOS

RADOSGW

APP

native

REST

LIBRADOS

RADOSGW

APP

89

RADOS Gateway:

•  REST-based interface to RADOS

•  Supports buckets, accounting

•  Compatible with S3 and Swift applications

90

RADOS A reliable, autonomous, distributed object store comprised of self-healing, self-managing,

intelligent storage nodes

LIBRADOS

A library allowing

apps to directly

access RADOS, with support for

C, C++, Java,

Python, Ruby,

and PHP

CEPH FS A POSIX-compliant

distributed file system, with a Linux

kernel client and

support for FUSE

RADOSGW A bucket-based REST

gateway, compatible with S3 and Swift

APP APP HOST/VM CLIENT

RBD A reliable and fully-

distributed block device, with a Linux

kernel client and a

QEMU/KVM driver

91

M

M

M

VM

LIBRADOS LIBRBD

VIRTUALIZATION CONTAINER

LIBRADOS

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M

M

M

LIBRBD

CONTAINER

LIBRADOS LIBRBD

CONTAINER VM

LIBRADOS

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M

M

M

KRBD (KERNEL MODULE)

HOST

RADOS Block Device:

• Storage of virtual disks in RADOS

• Allows decoupling of VMs and

containers

• Live migration!

• Images are striped across the

cluster

• Thin-provisioning

• Snapshots and cloning

LIBRADOS

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M

M

M

VM

LIBRBD

VIRTUALIZATION CONTAINER

HOW DO YOU

SPIN UP

THOUSANDS OF VMs

INSTANTLY

AND

EFFICIENTLY?

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144

117

0 0 0 0

instant copy

= 144

4 144

118

CLIENT

write

write

write

= 148

write

4 144

119

CLIENT read

read

read

= 148

29

local disk(VM images)

Novacompute

Glance(templates)

read X

X

X'

old-style VM image creation

● ephemeral

● expensive to create

Why use block storage?

• Persistent• More familiar to users

• Not tied to a single host• Decouples compute and storage• Enables Live migration

• Extra capabilities of storage system• Efficient snapshots• Different types of storage available• Cloning for fast restore or scaling

31

CinderAPI

Cindervolume

create image from X

X

Cinder volume creation

Glance(templates)

volume driver

locate X

location of X

read X

X'

reference to X'

flexibility in where VM images are stored

32

CinderAPI

Cindervolume

create image from X

X

Efficient volume creation

Glance(templates)

volume driver

locate X

location of X

clone X to X'

X'

reference to X'

fast CoW clone

X' complete

Questions?

Josh Durgin

[email protected]

jdurgin on freenode

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