Ceph Internals & Data Processing Capabilities - SUSECON · Ceph Internals & Data Processing Capabilities Joao Eduardo Luis Senior Software Engineer [email protected] / [email protected]

Ceph Internals & Data Processing Capabilities

Joao Eduardo Luis Senior Software Engineer [email protected] / [email protected]

2

OVERALL ARCHITECTURE

RGWweb services gateway for

object storage, compatible with S3 and Swift

LIBRADOSclient library allowing apps to access RADOS (C, C++, Java, Python, Ruby, PHP)

RADOSsoftware-based, reliable, autonomous, distributed object store comprised of

self-healing, self-managing, intelligent storage nodes and lightweight monitors

RBDreliable, fully-distributed block device with cloud

platform integration

CEPHFSdistributed file system

with POSIX semantics and scale-out metadata

management

APP HOST/VM CLIENT

3

OVERALL ARCHITECTURE

RGWweb services gateway for

object storage, compatible with S3 and Swift

LIBRADOSclient library allowing apps to access RADOS (C, C++, Java, Python, Ruby, PHP)

RADOSsoftware-based, reliable, autonomous, distributed object store comprised of

self-healing, self-managing, intelligent storage nodes and lightweight monitors

RBDreliable, fully-distributed block device with cloud

platform integration

CEPHFSdistributed file system

with POSIX semantics and scale-out metadata

management

APP HOST/VM CLIENT

4

RADOS CLUSTER

APPLICATION

M M

M M

M

RADOS CLUSTER

5

RADOS COMPONENTS

OSDs‒ Smart storage

‒ Resilient, Distributed, Self-healing, etc

‒ 100's to thousands

Monitors‒ Keep track of cluster state

‒ Always consistent, or otherwise...

‒ 3, 5, 7, ...M

6

OBJECT STORAGE DAEMONS

FS

DISK

OSD

DISK

OSD

FS

DISK

OSD

FS

DISK

OSD

FS

M

M

M

7

WHERE IS MY OBJECT?

??APPLICATION

M

M

M

OBJECT

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METADATA SERVER?

1

APPLICATION

M

M

M

2

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CALCULATED PLACEMENT?

APPLICATION

M

M

MA-G

H-N

O-T

U-Z

??

F

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CRUSH

RADOS CLUSTER

OBJECTS

10

01

01

10

10

01

11

01

10

01

01

10

10

01 11

01

1001

0110 10 01

11

01

PLACEMENT GROUPS(PGs)

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CRUSH

RADOS CLUSTER

OBJECT

10

01

01

10

10

01 11

01

1001

0110 10 01

11

01

10

10

12

CRUSH – Failure?

RADOS CLUSTER

OBJECT

10

01

01

10

10

01 11

01

1001

0110 10 01

11

01

10

13

DATA ORGANIZED INTO POOLS

CLUSTER

OBJECTS

10

01

01

10

10

01 11

01

1001

0110 10 01

11

01

POOLS(CONTAINING PGs)

10

01

11

01

10

01

01

10

01

10

10

01

11

01

10

01

10 01 10 11

01

11

01

10

10

01

01

01

10

10

01

01

POOLA

POOLB

POOL C

POOLDOBJECTS

OBJECTS

OBJECTS

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POOLS

OBJECT

REPLICATED POOL

CEPH STORAGE CLUSTER

ERASURE CODED POOL

CEPH STORAGE CLUSTER

COPY COPY

OBJECT

31 2 X Y

COPY4

Full copies of stored objects

Very high durability

3x (200% overhead)

Quicker recovery

One copy plus parity

Cost-effective durability

1.5x (50% overhead)

Expensive recovery

LIBRADOS

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OVERALL ARCHITECTURE

RGWweb services gateway for

object storage, compatible with S3 and Swift

LIBRADOSclient library allowing apps to access RADOS (C, C++, Java, Python, Ruby, PHP)

RADOSsoftware-based, reliable, autonomous, distributed object store comprised of

self-healing, self-managing, intelligent storage nodes and lightweight monitors

RBDreliable, fully-distributed block device with cloud

platform integration

CEPHFSdistributed file system

with POSIX semantics and scale-out metadata

management

APP HOST/VM CLIENT

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EXAMPLE `HELLO WORLD!`

Connect to cluster

Create pool

Atomic (re)write

#include <rados/librados.hpp>

librados::Rados rados;rados.init(“admin”);rados.connect();

rados.pool_create(“hello_pool”);

librados::IoCtx ctx;rados.ioctx_create(“hello_pool”, ctx);

bufferlist data;data.append(“hello world!”);ctx.write_full(“hello_object”, data);

bufferlist attr;attr.append(“1”);ctx.setxattr(“hello_object”, “version”, attr);

rados.shutdown();

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LIBRADOS

APPLIBRADOS

MMM

object “foo”

pool “bar”

0x2d87c31

pg 2.c31id 2

mod pg_num

clusterstateCRUSH

hierarchy

osdmap

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COMPOUND OBJECT OPERATIONS

Connect to cluster

Create pool

#include <rados/librados.hpp>

librados::Rados rados;rados.init(“admin”);rados.connect();

rados.pool_create(“hello_pool”);

librados::IoCtx ctx;rados.ioctx_create(“hello_pool”, ctx);

ObjectWriteOperation op;

bufferlist data;data.append(“hello world!”);op.write_full(data);

bufferlist attr;attr.append(“1”);op.setxattr(“version”, attr);

ctx.operate(“hello_object”, &op);

rados.shutdown();

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AP

PLI

BR

AD

OS

RADOS OBJECT CLASSES

put_foo()

calc_bar()

my_foo.soput_foo(data)

read(“bar”, data)

21

EXAMPLE

int compute_md5(cls_method_context_t hctx, bufferlist *in, bufferlist *out){ size_t size; int ret = cls_cxx_stat(hctx, &size, NULL); if (ret < 0) return ret;

bufferlist data; ret = cls_cxx_read(hctx, 0, size, data); if (ret < 0) return ret;

byte digest[AES::BLOCKSIZE]; MD5().CalculateDigest(digest, (byte*)data.c_str(), data.length());

out->append(digest, sizeof(digest));

return 0;}

bufferlist input, output;

ioctx.exec(“hello_object”, “hello_hash_class”, “compute_md5”, input, output);

ObjectReadOperation op;

uint64_t size;time_t m_time;op.stat(&size, &m_time, NULL);

bufferlist in, out;op.exec(“hello_hash_class”, “compute_md5”, in, &out);

int r = op.operate(“hello_object”, &op);

Server-side class (hello_hash_class) librados client

Compound operations

22

REAL APPLICATIONS

• Cooperative Locking

• Simple Object Reference Counting

• Image manipulation

• RADOS Block Device (RBD) & Gateway (RGW)

sources in src/cls/*

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DYNAMIC OBJECT CLASSES IN LUA

• Noah Watkins (UCSC / Red Hat)‒ http://ceph.com/rados/dynamic-object-interfaces-with-lua/

local script = [[function say_hello(input, output) output:append("Hello, ") if #input == 0 then output:append("world") else output:append(input:str()) end output:append("!")endcls.register(say_hello)]]

local ret, outdata = clslua.exec(ioctx, "oid", script, "say_hello", "")print(outdata)

local ret, outdata = clslua.exec(ioctx, "oid", script, "say_hello", "John")print(outdata)

Thank you.

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[email protected]@lists.ceph.com#ceph / #ceph-devel @ OFTCwww.ceph.com

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