HC VIN CNG NGH BU CHNH VIN THNG

---------------------------------------

Nguyn Vn Hip

O HA MY CH THEO M HNH IN TON M MY TI KINDERWORLD

Chuyn ngnh: Truyn d liu v mng my tnh

M s: 60.48.15

TM TT LUN VN THC S

H NI - 2013

Lun vn c hon thnh ti:

HC VIN CNG NGH BU CHNH VIN THNG

Ngi hng dn khoa hc: TS. ng Th Thu Hin

Phn bin 1:

Phn bin 2: ..

Lun vn s c bo v trc Hi ng chm lun vn thc s ti Hc vin Cng ngh Bu

chnh Vin thng

Vo lc: ....... gi ....... ngy ....... thng ....... .. nm ...............

C th tm hiu lun vn ti:

- Th vin ca Hc vin Cng ngh Bu chnh Vin thng

H NI - 2013

1

LI CM N

Ti xin gi li cm n ti cc ging vin ca khoa

Cng ngh thng tin - Hc vin Bu Chnh Vin Thng,

ni cho ti nhng kin thc lm nn tng ti hon

thnh c lun vn ny. Ti by t lng bit n su sc

ti TS. ng Th Thu Hin Trng H GT Vn ti -

ngi hng dn khoa hc - ngi ch bo tn tnh v

truyn th cho ti ngun cm hng nghin cu v a ti

vo lnh vc khoa hc ny. Ti xin cm n ThS.

Thanh Thy HGTVT c nhng gp , nhn xt v

gip ti trong qu trnh lm lun vn.

Cui cng, ti xin by t lng bit n ti gia nh,

v cc bn b chia s v ng vin ti hon thnh lun

vn.

2

M U

Nick van der Zweep - Gim c phn mm c s

h tng ESS v o ha ca HP ni: Mt s trung tm

d liu ch s dng 10% n 30% nng lc x l hin c

ca h. o ha gip nhiu t chc c th chia s cc ti

nguyn cng ngh thng tin theo cch tn t gi thnh

nht, lm cho c s h tng cng ngh thng tin tr nn

linh ng v bo m cung cp mt cch t ng vi

nhng nhu cu cn thit.

S dng cng ngh o ha em n cho ngi dng s

tin ch. Vic c th chy nhiu h iu hnh ng thi

trn cng mt my tnh s thun tin cho vic hc tp

nghin cu v nh gi mt sn phm h iu hnh hay

mt phn mm tin ch no . Nhng khng ngng li

, nhng kh nng v li ch ca o ho cn hn th v

ni gt hi c nhiu thnh cng v to nn thng hiu

ca cng ngh o ha chnh l trong mi trng h

thng my ch ng dng v h thng mng.

Hin nay c nhiu nh cung cp cc sn phm my

ch v phn mm u ch tm u t nghin cu v pht

3

trin cng ngh ny nh l HP, IBM, Microsoft v

VMware. Tuy nhin, ti Vit Nam, o ha my ch thc

s khng c quan tm cho n nhng nm gn y. Do

cn nhiu vn v cng ngh v ngi dng cha thc

s quan tm ti li ch v cn thiu mt i ng am hiu

v cng ngh ny nn vic p dng n vo h thng l rt

d dt. Nhng khi i mt vi thc trng khng hong ca

nn kinh t ton cu th bt k mt doanh nghip no cng

ch tm tm mt gii php tit kim hn. y cng l

lc cng ngh o ha tm c ch ng vng chc trong

lnh vc cng ngh thng tin trn th gii.

Cng vi o ha th in ton m my cng ang l mt

trong nhng cng ngh c thu ht c s quan tm

ca c gii cng ngh trong thi gian gn y. in ton

m my mc h tng c s (IaaS) l mt loi h thng

phn b v x l song gm cc my tnh o kt ni vi

nhau v c cung cp ng cho ngi dng nh mt

hoc nhiu ti nguyn ng nht da trn s tha thun

dch v gia nh cung cp v ngi s dng.

Nhn thc c s cn thit v kh nng pht trin

mnh m ca cng ngh o ha theo m hnh in ton

4

m my trong tng lai, lun vn o ha my ch theo

m hnh in ton ti KINDERWORLD ca ti

phn no gii thiu c ci nhn tng quan v hai cng

ngh ny, ng thi a ra nhng gii php c bn cho

mt m hnh o ha my ch quy m nh. B cc ca

lun vn gm c 3 chng:

Chng 1: Tng quan v cng ngh o ha: tp trung

trnh by gii thiu v cng ngh o ha v mt s cng

ngh o ha my ch.

Chng 2: Cng ngh in ton m my: trnh by tng

quan v cng ngh in ton m my v tng o ha

my ch theo m hnh in ton m my.

Chng 3: Thit k v trin khai gii php o ha my

ch ti KINDERWORLD: xy dng m hnh o ha my

ch gn lin vi cloud computing theo IaaS.

Phn kt lun, phn ny trnh by tm tt v cc ni dung

thc hin trong lun vn ny, ng thi a ra nhng vn

nghin cu tip theo cho tng lai.

5

Chng 1- TNG QUAN V CNG NGH

O HA

1.1 Cng ngh o ha

1.1.1 Gii thiu v cng ngh o ha

Khi nim

o ha l mt bc tin mnh m cho vic ti u

ha vic trin khai xy dng mt cch hiu qu ngun ti

nguyn h thng bng cch tch ri mi lin kt vn c

gia phn cng, phn mm, d liu, ng truyn, lu tr

thnh tng phn ring bit.

Hnh 1.1: Mt server vt l trong h thng o ha

6

1.1.2 u nhc im ca o ha

u im

- Qun l n gin

- Trin khai nhanh

- Phc hi v lu tr h thng nhanh

- Cn bng ti v phn phi ti nguyn linh hot

- Tit kim

Nhc im

- Vn bo mt v lu tr vt l

- Yu cu my phi c cu hnh cao

- Nhc im khi qun l tp trung

1.1.3 Phn loi o ha

- Type 1 Virtual Machine Manager: Hypervisor

Hypervisor l mt lp phn mm nm ngay trn

phn cng hoc bn di mt hoc nhiu h iu hnh.

7

- Type 2 Virtual Machine Manager

My o Java, hoc mt v d khc l common

language runtime (CLR). Trong c 2 v d s bt u vi

h iu hnh host ngha l h iu hnh c ci t

trc tip bn trn phn cng vt l.

- Hybrid

Kin trc o ha mi hn l Hybrid, trong cc

my ch o (VMM), chy song song vi h iu hnh

my ch (OS).

Phng php Hybird VMM c s dng ngy nay

trong hai gii php o ha ph bin t Microsoft l

Microsoft Virtual PC 2007 v Microsoft Virtual Server

2005 R2 .

1.1.4 Cc cng ngh h tr o ha

- Cng ngh my o (Virtual Machine)

- Cng ngh RAID

8

1.2 Mt s cng ngh o ha my ch

1.2.1 Cng ngh Vmware ESX Server

1.2.2 Cng ngh Hyper-V

Hyper-V l cng ngh o ha server th h mi ca

Microsoft v l thnh phn quan trng trong h iu hnh

Windows Server 2008. Vi Hyper-V, Microsoft cung cp

mt nn tng o ha mnh v linh hot, c th p ng

nhu cu o ha mi cp cho mi trng doanh nghip.

Hyper-V c 3 phin bn Windows Server 2008 64

bit l Standard (mt my o), Enterprise (4 my o) v

DataCenter (khng gii hn s lng my o). Tuy nhin

n h tr h iu hnh khch trn c 32-bit v 64-bit l

im ni bt ca Hyper-V.

9

Chng 2 - TNG QUAN V IN

TON M MY

2.1 Gii thiu in ton m my - Cloud

computing

2.1.1 Khi nim Cloud Computing

m my (cloud) l biu tng tng trng cho

Internet v thng c s dng trong cc m hnh, s

mng my tnh. Do , in ton m my c hiu nh

cch thc p dng cc k thut in ton da trn Internet.

C th hn, l mt m hnh m mi thng tin u c

lu tr, tnh ton, x l trong cc my ch t trn

Internet. Ngi s dng c th lm vic vi cc thng tin

m khng cn phi hiu bit v cng ngh, k thut v

h tng c s ca m my.

2.1.2 Li ch v thch thc Cloud Computing

2.1.2.1 Li ch

- S dng cc ti nguyn tnh ton ng

10

- Gim chi ph

- Gim phc tp trong c cu ca doanh nghip

Tng kh nng s dng ti nguyn tnh ton

2.1.2.2 Thch thc

- Chi ph

- Cng tc qun l

- Tnh sn sng

- Tnh ring t

2.1.3 Xu th Cloud Computing Vit Nam v trn

th gii

2.1.4 Cc gii php

- Vn v lu tr d liu

- Vn sc mnh tnh ton

- Vn cung cp ti nguyn, phn mm

2.1.5 Cc m hnh trin khai Cloud Computing

11

2.1.5.1 Public Cloud

Cc dch v Cloud c nh cung cp dch v cung

cp cho mi ngi s dng rng ri. Cc dch v c

cung cp v qun l bi mt nh cung cp dch v v cc

ng dng ca ngi dng u nm trn h thng Cloud.

Ngi s dng dch v s c li l chi ph u t

thp, gim thiu ri ro do nh cung cp dch v gnh

vc nhim v qun l h thng, c s h tng, bo mt

Mt li ch khc ca m hnh ny l cung cp kh nng co

gin (m rng hoc thu nh) theo yu cu ca ngi s

dng.

2.1.5.2 Private Cloud

Trong m hnh Private Cloud, c s h tng v cc

dch v c xy dng phc v cho mt t chc

(doanh nghip) duy nht. iu ny gip cho doanh nghip

c th kim sot ti a i vi d liu, bo mt v cht

lng dch v. Doanh nghip s hu c s h tng v

qun l cc ng dng c trin khai trn . Private

Cloud c th c xy dng v qun l bi chnh i ng

12

IT ca doanh nghip hoc c th thu mt nh cung cp

dch v m nhim cng vic ny.

Nh vy, mc d tn chi ph u t nhng Private

Cloud li cung cp cho doanh nghip kh nng kim sot

v qun l cht ch nhng d liu quan trng.

2.1.5.3 Hybird Cloud

Nh chng ta phn tch trn, Public Cloud d

p dng, chi ph thp nhng khng an ton. Ngc li,

Private Cloud an ton hn nhng tn chi ph v kh p

dng. Do nu kt hp c hai m hnh ny li vi

nhau th s khai thc u im ca tng m hnh. l

tng hnh thnh m hnh Hybrid Cloud.

Hybrid Cloud l s kt hp ca Public Cloud v

Private Cloud. Trong doanh nghip s out-source cc

chc nng nghip v v d liu khng quan trng, s

dng cc dch v Public Cloud gii quyt v x l cc

d liu ny. ng thi, doanh nghip s gi li cc chc

nng nghip v v d liu ti quan trng trong tm kim

sot (Private Cloud).

13

2.2 o ha my ch theo m hnh in ton m

my

Mt trong nhng tng quan trng nht ca

cloud computing l kh nng m rng v cng ngh ch

cht l cng ngh o ha. o ha cho php s dng tt

hn mt server bng cch kt hp cc h iu hnh v cc

ng dng trn mt my tnh chia s n l. o ha cng

cho php di tr trc tuyn (online migration) khi mt

server qu ti, mt instance ca h iu hnh (v cc ng

dng trn ) c th di tr n mt server mi, t ti hn.

14

Chng 3 - THIT K V TRIN KHAI

GII PHP O HA MY CH TI

KINDERWORLD

3.1 Phn tch cc yu cu v cc dch v cng ngh

thng tin ca Kinderworld

3.1.1 Gii thiu v Kinderworld

Tp on gio dc Kinderworld c thnh lp

nm 1986 ti Singapore v c mt ti Vit Nam t nm

2000. Qua hn 10 nm hot ng ti Vit Nam,

KinderWorld lun chng t u th vt tri trong lnh vc

gio dc Vit Nam v c bit n nh l mt trong

nhng h thng trng quc t hng u Vit Nam.

Hin nay h thng cc trng hc quc t ca

KinderWorld pht trin ti cc trng mu gio Quc

t KinderWorld ti H Ni, Nng, Hu, Bnh Dng

v TP H Ch Minh, Trng Tiu hc v Trung hc Quc

t Singapore ti H Ni, Nng, Hu, Bnh Dng v

Tp H Ch Minh. KinderWorld tin tng vo vic em

15

n cho hc sinh mt chng trnh hc tp a dng, kt

hp gia cc gi tr phng ng vi xu hng quc t

hin i.

3.1.2 Nhu cu v cc dch v mng ti Kinderworld

Nm 2012, lnh o Kinderworld bt tay vo r

sot nh gi li h thng cng ngh thng tin ca mnh.

Bc u tin s u t, nng cp c s h tng mng, ti

u ha h thng my ch.

Nm 2012, Kinderworld min bc c khong hn

2020 hc sinh, c 10 Server vt l (Intel based) trn ton

h thng. Cc Server vt l bao gm nhiu chng loi

c trang b t nhiu Vendor khc nhau nh: IBM

System x, HP (Tower, Rack-mount), FPT Elead.

H thng lu tr DAS Storage khng hp nht bao

gm nhiu t a khc nhau: IBM DS 4100, DS 4500, DS

4700 Series. Vic s dng ti nguyn cha hiu qu, qu

trnh vn hnh qun l gp t nhiu kh khn khi nhu cu

cp pht,chia s ti nguyn, d liu lu tr thng xuyn

hn v a dng hn. Nm 2013, s lng hc sinh ngy

cng gia tng, khong hn 3000 hc sinh, nhu cu v

email mi hc sinh c 100MB d liu email, s lng

16

nhn vin tng ln, nhu cu v qun l nhn vin bng

cch ng nhp vo domain..v vy h thng cn phi

nng cp, ti u ha h thng: mua thm server, chi ph

bo tr, sa cha, tng dung lng lu tr, ngoi ra chng

ta cn phi tnh ton kh nng m rng, nng cp thit b,

phi kim sot vic bo mt d liu cng nh tnh sn

sng cao ca d liu.

C nhiu phng php thc hin ti u ha h thng

my ch, trong o ha my ch l mt trong nhng

phng php c nhc n rt nhiu trong thi gian gn

y. o ha my ch l phng php c th p dng

mi h thng my ch m khng pht sinh thm chi ph

u t. N l mt bin php rt tt trong vic ti u ha

h thng vi vic hp nht cc ngun ti nguyn ca my

ch.

H thng Kinderworld group c rt nhiu my ch,

mi my ch c t nhiu ni khc nhau, v vy vic

truy xut hay bo tr d liu l rt kh khn. V vy tt c

cc d liu u c o ha trong m my gip doanh

nghip gim thiu chi ph vn hnh bo tr bo dng.

17

Gii php xy dng mt private cloud: Trong m

hnh Private Cloud, c s h tng v cc dch v c xy

dng phc v cho mt t chc (doanh nghip) duy

nht. iu ny gip cho doanh nghip c th kim sot ti

a i vi d liu, bo mt v cht lng dch v. Doanh

nghip s hu c s h tng v qun l cc ng dng c

trin khai trn . Private Cloud c th c xy dng v

qun l bi chnh i ng IT ca doanh nghip hoc c

th thu mt nh cung cp dch v m nhim cng vic

ny. Nh vy, mc d tn chi ph u t nhng Private

Cloud li cung cp cho doanh nghip kh nng kim sot

v qun l cht ch nhng d liu quan trng.

Tip nhn yu cu: ghi nhn li cc thng tin chi tit v

yu cu h tr nh: loi yu cu (h tr, li pht sinh, yu

cu nng cp sa i,), thng tin khch hng hoc

ngi yu cu, hnh thc tip nhn (in thoi, email,

chat,),

Phn cng ngi x l:

Qun l kho tri thc (knowlegde base)

18

3.2 Thit k gii php

Nh phn tch trn, mt yu cu ct t ra

y l quy hoch li h thng mng my ch p ng

c:

Cc dch v mng ca Kinderwworld bao gm:

web, email, domain name, ng dng qun l o

to, ng dng qun l ti nguyn, ng dng qun

l ti chnh va chy trong mng cc b va chy

trn internet.

H thng n nh, kh nng chu li v phc hi

sau li (failover), tnh sn sng cao (high available)

H thng mm do, linh hot theo nhu cu ca

ngi dng, c kh nng m rng d dng khi cn

thit (do cc yu cu gia tng nh quy m o to,

dch v mi pht sinh )

Ti s dng cc thit b phn cng c, tit kim

chi ph u t thm mc ti a

H thng c t trong Kinderworld v c

kim sot bi Kinderworld.

19

T cc yu cu t ra trn v kh nng h tr ca

cng ngh thng tin hin nay, chng ti ngh khng

tip cn theo cc gii php truyn thng m p dng in

ton m my mc IaaS (Infrastructure As A

Service) kt hp vi cng ngh o ha my ch xy

dng mt m my h tng ring (Private Cloud) p ng

c y cc yu cu ca quy hoch h thng mng

my ch ca Kinderworld.

M hnh ca thit k c minh ha trong cc hnh

nh di y:

Hnh 3.1: M hnh Ti nguyn c chia s (Shared

Resource)

Web

server

Mail

server

DC

Application

server

Web client

Mail client

Login

client

Application client

20

Trong m hnh ny, mt server vt l c o ha

thnh 04 server: web server, mail server, server qun l

min DC (Domain Controller) v server cha cc ng

dng ca ring Kinderworld.

Mi server o nh web server, mail server, u

c a ch IP ring v c lp vi cc server khc v

phng din cung cp dch v n cc chng trnh khch

ca n.

Ty theo nhu cu s dng dch v ca ngi dng

m chng ta c th to ra nhiu server o hay khng trn

cc server vt l. V d nh c thi im nhiu ngi truy

cp vo website ca Nh trng th chng ta c th to

thm cc web server o trn cc server vt l tht khc

mt cch theo thi gian thc v t ng. Tuy nhin, nu

sau lng ngi dng truy cp vo website li gim

th chng ta thu hi web server o ti nguyn cho cc

server khc (mail server, DC application server).

Vi m hnh ny, chng ta thy, ti nguyn

c s dng mt cch hp l ti a v co gin theo

thi gian thc ca nhu cu ngi dng thc. Cc server o

21

c to ra trn cc server thc theo ng nhu cu ca

ngi dung theo thi gian thc, khng cn tnh trng c

server th qu ti, c server th khng c ngi dng hoc

rt t ngi dng, d tha ti nguyn m cc server khc

li khng c dng phn d tha .

Tuy nhin, p ng kh nng failover, high available,

ca h thng th m hnh ny cha . Chng ti a

ra m hnh tip theo ly ct li t m hnh trn v thm

vo cc kh nng clustering gia cc server vt l. M

hnh c minh ha trong hnh nh di y:

22

Hnh 3.2 : M hnh ti nguyn chia s kt hp vi cng

ngh clustering

23

Trong m hnh ny:

(1) Trn cc server vt l ci t Hypervisor

(2) Hypervisor to v qun l cc server o trn

mi server vt l.

(3) File cu hnh ca cc server o c t

trong thit b lu tr chia s chung tt c

cc Hypervisor trn cc server vt l u c

th truy cp c

Cc server vt l c qun l bi VIM (Vendor

Independent Messaging). Cc server vt l s nh

k gi cc thng ip trng thi ca mnh v cho

VIM. Khi mt server vt l no b down. VIM

s khng nhn c thng ip trng thi ca n

trong khong thi gian timeout, n s iu khin

server vt l khc trong cm clustering n qun l

thay th server b down.

Cc server vt l trong cm clustering c hot ng

theo ch active stand by. Tc l, ti mt thi im ch

c 1 (hoc mt vi) server ch hot ng active, cc

24

server khc ch ng (stand by) d phng. Gi s

server 2 ang hot ng ch active , server 3 ch

stand by. Server 2 b down v mt l do no , VIM s

khng nhn c thng ip trng thi nh k ca server

2. Khi , VIM hiu rng server 2 b down, n s

nh thc server 3 v di tr server o C (Virtual Server

C) sang server 3. C th server o C s phi khi ng li

mi tip tc cng vic. lm c iu , cn cng c

di tr my o thi gian thc (live VM migration) c

ci t trn cc Hypervisor.

Nh vy, vi m hnh thit k th 2, chng ti

thc hin c y cc yu cu ca quy hoch h

thng my ch ti Kinderworld. Thit k ny c trin

khai ti Kinderwworld v c kim sot bi i ng

nhn vin cng ngh thng tin trong Kinderworld m bo

y l mt h tng m my ring.

3.3 Trin khai gii php

3.3.1 Mc tiu

Xy dng m hnh o ha my ch gn lin vi cloud

computing theo IaaS:

25

Lp phn cng (Hardware Layer): cc my Hyper-

V server, cc my DC (Domain Controller), cc

thit b lu tr, ng truyn

Lp o ha ( Virtualization Layer): Hyper-V role

trong Windows Server 2008 R2

Lp t ng ha (Automatic Layer): Lp t ng

ha bao gm cc cng c nh Windows

PowerShell 2.0, Windows Management

Instrumentation (WMI) v WS- Management,

Hyper-V Tool.

Lp qun l (Management Layer): Lp qun l

theo SCVMM (System Center Vitual Machine

Manager), m nhim vic qun l, t ng ha

vic cp nht, trin khai ci t, sao lu v theo di

h thng.

Sau khi xy dng h thng thc hin c cc chc nng

sau:

To, qun l, v sa i cu hnh cc my o.

Qun l cc my o t xa.

26

Phn quyn v cc hnh ng cho user i vi tng

my o

Trin khai gii php failover cluster cho cc my

vt l

nh gi hiu nng s dng ca cc my o, cng

nh cc my vt l qua SCVMM

Di tr cc my vi thi gian downtime khng ng

k

To v qun l cc my o qua giao din web

3.3.2 Ni dung

3.3.2.1 Ci t Hyper-V role, qun l my o vi

Hyper-V Manager

- Ci t Hyper-V role trong Windows Server

2008R2

- To v qun l my o thng qua Hyper-V

Manager.

3.3.2.2 Ci t v cu hnh Hyper-V Tools qun l

t xa, phn quyn cho user

- Phn quyn v cc hnh ng cho mi user i vi

tng my o.

27

- Ci t Hyper-V Tool trn Windows 7 qun l

my o t xa.

3.3.2.3 Trin khai Hyper-V Cluster

- To cc node ca cluster chnh l cc my Hyper-V

server

- Xy dng cc my o trn Cluster Share Volume

- Thc hin di tr cc my o khi mt trong cc node

down.

3.3.2. 4 Trin khai qun l Hyper-V Server trn

System Center Vitual Machine Manager

- Ci t SCVMM

- Xy dng library, to cc template.

- Qun l hiu nng ca cc my o v cc my vt

l qua VMM Administrator Console.

3.3.2.5 Trin khai to v qun l my o qua trnh

duyt web

- Ci t SelfService Portal

- Phn quyn cho cc group user role.

28

- Truy cp giao din web to v qun l cc my

o.

3.3.3 Ci t

3.3.3.1 Ci t Hyper-V role, qun l my o vi

Hyper-V Manager

- Kim tra yu cu phn cng ca my

- Ci t Hyper V Role

- Khi to my o

- Snapshot my o

- Export Import my o

29

3.3.3.2 Trin khai v qun tr

- Ci t v cu hnh Hyper-V Tools qun l t xa,

phn quyn cho user

- Trin khai Hyper-V Cluster

- Trin khai qun l Hyper-V server trn System Center

Virtual Machine Manager

KT LUN

Qua nghin cu v tnh o ha trong cng ngh

in ton m my- Cloud Computing ta c th thy rng:

lun vn gii thiu v khi nim, kin trc, cng nh

cc u, nhc im ca hai cng ngh: o ha server v

30

in ton m my. Lun vn kt hp o ha v in

ton m my xy dng ln gii php o ha server

theo m hnh Cloud Computing. Lun vn a ra

c m hnh v cch trin khai khi xy dng o ha

server theo m hnh Cloud Computing ti cng ty

Kinderworld. Sau khi trin khai lun vn t c kt

qu sau :

To, qun l v sa i cu hnh cc my o.

Qun l cc my o t xa.

Phn quyn v cc hnh ng cho user i vi tng

my o.

Trin khai gii php failover cluster cho cc my

vt l

nh gi hiu nng s dng ca cc my o, cng

nh cc my vt l qua SCVMM.

Di tr cc my vi thi gian downtime khng ng

k

To v qun l cc my o qua giao din web.

Trong thi gian ti , nu c iu kin, ti s c

gng nghin cu pht trin cc ni dung sau:

31

Xy dng dch v o ha my ch cho cng ty c

phn trng t thc quc t Kinderworld.

Trin khai m hnh lp vn hnh (Orchestration

Layer), tch hp vi b System Center, gip xy dng h

thng qun tr v vn hnh trung tm tch hp d liu t

ng, ng thi h tr cc Workflow to cc quy trnh

IT.