Wrldwide Cnsulting Slutins WHITE PAPER Implementatin Guide 2 High Availability fr TFTP with Prvisining Services Implementatin Guide www.citrix.cm
Cntents Overview... 3 Optins... 4 DNS Rund Rbin Entry... 5 DHCP with Multiple Entries... 5 Prvisining Services PXE Bradcast... 5 Prvisining Services Bt Device Manager... 6 NetScaler Use Surce IP... 6 NetScaler Direct Server Return... 7 NetScaler Glbal Server Lad Balancing... 7 Summary... 8 Implementatin Guide... 9 Prerequisites... 10 NetScaler General Cnfiguratin... 14 NetScaler Use Surce IP... 17 NetScaler Direct Server Return... 22 NetScaler Glbal Server Lad Balancing... 28 Appendix A Envirnment Details... 35 Appendix B Reference Dcumentatin... 35 Revisin Histry... 37 Page 2
Overview Citrix Prvisining Services is a sftware streaming technlgy that allws servers and desktps t be prvisined and re-prvisined in real time frm a single shared-disk image 1. The service is cmmnly integrated with Citrix virtualizatin slutins t ptimize Operating System delivery and management. Often these slutins are critical t the peratin f rganizatins and require high availability. Prviding high availability fr Prvisining Services requires designing each cmpnent f the service withut a single pint f failure acrss the netwrk. The btstrap file, named ardbp32.bin, is a key cmpnent that must be delivered t Prvisining Services target devices in rder fr them t cmmunicate with Prvisining Services ver the netwrk. The btstrap file is typically delivered via Trivial File Transfer Prtcl (TFTP) services hsted n Prvisining Servers. This dcument fcuses specifically n cmparing high availability ptins fr delivery f the btstrap file t target devices via TFTP. The advantages and disadvantages f each ptin are utlined as well as the steps t implement the lad balancing ptins with NetScaler. The dcument scpe des nt include details f the implementatin r peratin f ther aspects f Prvisining Services. 1 http://supprt.citrix.cm/prddcs/tpic/technlgies/pvs-prvisining.html Page 3
Optins The ptins under cnsideratin share cmmn cmpnents including: Dynamic Hst Cnfiguratin Prtcl (DHCP) 2 : Prvides hsts with netwrking infrmatin they need t cmmunicate n the netwrk. It prvides a hst with an IP address, gateway, and DNS server(s) by default. Tw additinal ptins carry additinal infrmatin that are used by Prvisining Services target devices t btain their btstrap file. Optin 66: Defines the Bt Server Hst Name, which crrespnds t the TFTP Server DNS name r IP address Optin 67: Defines the Btfile Name, which is typically ardbp32.bin Pre-bt Executin Envirnment (PXE) 3 : Is a prgram included in cmputer firmware that enables it t bt ver the netwrk. It relies n DHCP t btain infrmatin necessary t bt. When a cmputer first attempts a PXE bt it bradcasts a DHCP request ver its Netwrk Interface Card (NIC)/(s). Trivial File Transfer Prtcl (TFTP) 4 : Prvides PXE clients with their btstrap file. Clients are typically ntified f the TFTP Server/(s) and the btstrap file name thrugh DHCP ptins. The lab envirnment used t implement the ptins has a TFTP service running n each Prvisining Services server, s they will be referenced as Prvisining Services/TFTP Servers. Dmain Name System (DNS) 5 : Allws cmmn names t be mapped t and frm IP addresses. By prviding dynamic allcatin f its directry infrmatin Prvisining Services target devices may be presented with different Prvisining Services/TFTP Server IP addresses prviding a rudimentary level f redundancy. The cre cncept with regards t prviding high availability t TFTP is being able t deliver the btstrap file t the Prvisining Services target device. Once the btstrap is delivered, the target device can cmmunicate t multiple Prvisining Services servers. There are many different ways fr prviding high availability fr the TFTP services, but the fllwing seven are the mst cmmn: 1. DNS Rund Rbin Entry 2. DHCP with Multiple Entries 3. Prvisining Services PXE Bradcast 2 http://en.wikipedia.rg/wiki/dynamic_hst_cnfiguratin_prtcl 3 http://en.wikipedia.rg/wiki/prebt_executin_envirnment 4 http://en.wikipedia.rg/wiki/trivial_file_transfer_prtcl 5 http://en.wikipedia.rg/wiki/dmain_name_system Page 4
4. Prvisining Services Bt Device Manager 5. NetScaler Use Surce IP (USIP) 6. NetScaler Direct Server Return (DSR) 7. NetScaler Glbal Server Lad Balancing (GSLB) DNS Rund Rbin Entry With this ptin, a TFTP server DNS name is carried in DHCP ptin 66. The DNS server then wuld have tw r mre A recrds defined fr the dmain name and cycle thrugh the list f recrds in rund rbin fashin in respnse t DNS queries. This prvides Prvisining Services target devices with redundancy in btaining their Btfile. Advantages f this ptin: It is easy t implement requiring limited changes t DHCP and DNS servers. Disadvantages f this ptin: It may nt mnitr the state f target TFTP servers, depending n the DNS server; therefre it culd ptentially send requests t servers that are nt functining. DHCP with Multiple Entries This ptin requires a DHCP implementatin that allws multiple Bt Server Hst Name entries t be carried within the ptin 66 field. Advantages f this ptin: It is easy t implement requiring limited changes t DHCP servers nly. Disadvantages f this ptin: It des nt mnitr the state f target TFTP servers; therefre it culd send requests t servers that are nt functining. Prvisining Services PXE Bradcast With this ptin a PXE bt server is hsted by Prvisining Services servers. After Prvisining Services target devices btain their IP address and gateway thrugh DHCP, they start bradcasting a TFTP bt request. Prvisining Services servers hsting PXE bt services n the same netwrk as the target devices will receive bt requests and respnd directly. Fr thse n different subnets, ruters may be cnfigured with a IP/UDP helper address entry, which allws the ruter t frward the initial Prvisining Services Client PXE bt bradcasts. Page 5
Withut the helper address, the requests wuld therwise be cntained within the subnet and unable t reach the PXE service. Advantages f this ptin: It is easy t implement, requiring limited changes t ruters nly. IP/UDP helper address entries are typically already cnfigured within netwrks t deliver client DHCP requests t DHCP server farms. Disadvantages f this ptin: It increases traffic n the netwrk and can present risks t its capacity in the event f a malfunctining PXE client, r virus that sends excessive bradcasts. Prvisining Services Bt Device Manager This Prvisining Services ptin is different than the ther ptins in that it des nt rely n the client PXE bting itself frm a TFTP Server. Rather, the Bt Device Manager creates a Btfile that the target device can btain via an ISO image munted t the virtual machine as a DVD drive. Fr this t be a high-availability ptin fr delivery f the Btfile, the netwrk share cntaining the ISO file must be redundant. Advantages f this ptin: It has limited reliance n the netwrk infrastructure. Disadvantages f this ptin: It requires changes t the target device bt prcess (bt via DVD instead f netwrk). Updating the ISO file is a manual prcess, which is why the addresses used within the file shuld be a fully qualified dmain name, whse IP address can be updated in DNS later. NetScaler Use Surce IP This ptin relies n the NetScaler t lad balance the target device s initial TFTP bt request t a TFTP Server. The target devices must btain the IP address f the NetScaler Virtual Server IP (VIP) thrugh DHCP ptin 66. Once the NetScaler receives the bt request, it is directed t ne f the TFTP servers frm the pl by changing the destinatin IP address. The surce IP address is nt changed, therefre the TFTP server replies t the target device directly. Advantages f this ptin: Prvides traffic surge prtectin fr servers. Page 6
Disadvantages f this ptin: Nne NetScaler Direct Server Return This ptin is similar t the NetScaler Use Surce IP ptin, but it makes its lad balancing decisin based n the frame MAC Address and des nt change the target destinatin IP address. Therefre the target TFTP Server must have a lpback IP address crrespnding t the NetScaler VIP. Advantages f this ptin: Prvides rbust scalability and availability as with the NetScaler-Use Surce IP ptin. Disadvantages f this ptin: Requires cnfiguring a lpback address n the TFTP Servers NetScaler Glbal Server Lad Balancing This ptin takes advantage f the NetScaler ability t integrate with DNS t cntrl respnses t queries while mnitring the availability f TFTP servers. Upn receiving a DNS query fr the TFTP bt server dmain name, the NetScaler dynamically respnds with the best ptin, accrding t the selectin algrithm cnfigured. Advantages f this ptin: Prvides availability mnitring f Prvisining Services/TFTP Servers Disadvantages f this ptin: Requires a NetScaler Platinum license r individual GSLB license Page 7
Summary Based n all f the ptins, the fllwing prvides a quick summary fr hw difficult they are t implement, hw scalable they are and hw fault tlerant they are (ability t identify issues and rerute requests apprpriately). Optin Difficulty Scalability Fault Tlerance DNS Rund Rbin Entry Lw Medium Lw DHCP with Multiple Entries Lw Lw Lw Prvisining Services PXE Bradcast Lw Medium Medium Prvisining Services Bt Manager Medium Medium High NetScaler Use Surce IP Lw High High NetScaler Direct Server Return Medium High High NetScaler Glbal Server Lad Balancing High High High Page 8
Implementatin Guide Of the previusly mentined high availability ptins fr TFTP, the three NetScaler ptins require additinal help in the setup/cnfiguratin. This sectin f the dcument fcuses n the implementatin f the NetScaler ptins. Fr the NetScaler ptins, the fllwing figure shws the cnceptual netwrk tplgy: Page 9
Prerequisites Belw is a cmplete list f cmpnents required t implement the NetScaler based ptins within a lab envirnment. Prerequisites The fllwing cmpnents must be installed t cmplete the implementatin scenaris cntained in this sectin Install a XenServer capable f hsting all required Virtual Machines (VMs) Install 2 Prvisining Services VMs including: The TFTP Server cmpnent cnfigured A license server & license A Prvisining Services Btstrap with pertinent cnfiguratin Install a Dmain Cntrller(DC) VM including: A DHCP service with pertinent ptins set A DNS service with pertinent A recrds cnfigured Install a Vyatta Ruter VM with pertinent settings cnfigured Install a NetScaler VM with pertinent settings cnfigured & license applied Install 2 Prvisining Services Clients One n the XenServer internal netwrk Prvisining Services TFTP Anther n the XenServer internal netwrk Prvisining Services TFTP2 Screensht Descriptin Install a XenServer XenServer versin 5.6_SP2 running n an HP Prliant 380 with 16MB RAM and an internal HD was used fr this setup The XenServer hsts 6 VMs described in the fllwing blcks and 3 Netwrks described belw Prvisining Services TFTP is an internal netwrk that crrespnds t subnet 192.168.0.0/24 Prvisining Services TFTP2 is an internal netwrk that crrespnds t subnet 10.95.95.0/24 Netwrk 1 crrespnds t an external netwrk used fr management access nly that crrespnds t subnet 172.17.2.0/24 See Appendix B - Reference Dcumentatin fr mre infrmatin regarding installatin Page 10
Prerequisites Install a NetScaler VM NetScaler versin 9.3_51_nc Add an interface t netwrk Prvisining Services - TFTP NOTE: The NetScaler shuld be cnfigured in a High Availability pair See Appendix B - Reference Dcumentatin fr mre infrmatin regarding installatin Install a Vyatta Ruter VM Vyatta Versin 2.6.35-1 Add an interface t netwrk Prvisining Services - TFTP Add an interface t netwrk Prvisining Services TFTP2 See Appendix B - Reference Dcumentatin fr mre infrmatin regarding installatin Install a Dmain Cntrller with DHCP and DNS Rles Add an interface t Prvisining Services TFTP Add an interface t Prvisining Services TFTP2 Add an interface t Netwrk 1 See Appendix B - Reference Dcumentatin fr mre infrmatin regarding installatin Cnfigure Dmain Cntrller Create Dmain pvslab.cm See Appendix B - Reference Dcumentatin fr mre infrmatin regarding installatin Page 11
Prerequisites Cnfigure DHCP Server Open the Windws Server Manager Select the DHCP Server Rle Cnfigure Scpe 192.168.0.0 crrespnding t netwrk Prvisining Services TFTP1 with Address Pl 192.168.0.50-192.168.0.59 Cnfigure Scpe 10.95.95.0 crrespnding t netwrk Prvisining Services TFTP2 with Address Pl 10.95.95.50-10.95.95.59 See Appendix B - Reference Dcumentatin fr mre infrmatin regarding installatin Install Prvisining Services Client VMs Prvisining Services Client1 is a XenServer VM with an interface n an internal netwrk Prvisining Services TFTP Prvisining Services Client2 is a XenServer VM with an interface n an internal netwrk Prvisining Services TFTP2 Set Prvisining Services client Bt Optin: Select the Prvisining Services Client 1 VM Select General Tab Select Prperties Select Bt Optins Specify: Netwrk and ensure ther ptins are unchecked Repeat fr the Prvisining Services Client 2 VM See Appendix B - Reference Dcumentatin fr mre infrmatin regarding installatin Page 12
Prerequisites Install Prvisining Services/TFTP Server VMs 2: Fr bth Prvisining Services/TFTP Server 1 & Add an interface t Prvisining Services TFTP Add an interface t Netwrk 1 Install Prvisining Services Versin 5.6.2 including: TFTP Server Prvisining Services Btstrap with pertinent cnfiguratin See Appendix B - Reference Dcumentatin fr mre infrmatin regarding installatin Page 13
NetScaler General Cnfiguratin Base Cnfiguratin Screensht Descriptin Cnfigure the NetScaler with a NetScaler IP (NSIP) address and a default gateway. 2 Dwnlad yur license and the latest NetScaler firmware frm www.mycitrix.cm. Page 14
Base Cnfiguratin Screensht Descriptin Cnnect t the NetScaler Enter the NetScaler s IP Address (NSIP) in the web brwser: http://192.168.0.95 Lg int the Cnfiguratin system with the ID and Passwrd NOTE: The default credentials are: Username = nsrt Passwrd = nsrt Apply license file Under: >System>License>Manage Licenses>Add Uplad yur license file t the NetScaler using the License utility 3 Upgrade the NetScaler Under: >NetScaler>Upgrade Wizard Fllw the wizard prmpts. Enter Yes when prmpted whether t rebt. Re-cnnect t the NetScaler after it has rebted Page 15
Base Cnfiguratin Screensht Descriptin Enable Lad Balancing Under: >System>Settings>Cnfigure Basic Features Select: Enable Lad Balancing Add Prvisining Services/TFTP Servers Under: >Lad Balancing>Servers In rder t lad balance TFTP services, the servers hsting the service must first be defined by ding the fllwing: Select Add frm the bttm menu bar In the Create Server windw, enter in the fllwing infrmatin fr the first Prvisining Services/TFTP Server: Server Name: pvs-server1 IP Address: 192.168.0.98 Select Create Fr the secnd Prvisining Services/TFTP Server, enter in the fllwing: Server Name: pvs-server2 IP Address: 192.168.0.99 Select Create Select Clse Each Server entry shuld appear green. If nt check reachability frm the NetScaler SNIP t the servers Page 16
NetScaler Use Surce IP The netwrk tplgy pertaining t implementatin f this ptin is shwn in the fllwing figure: With this ptin, each f the Prvisining Services Client VMs are restarted and fllw the respective paths, utlined abve, sequentially t btain their btfile. Prvisining Services Client 1 Bradcasts a DHCP request, which is replied t by the DHCP Server carrying its IP address, Gateway, Bt Server Hst Name, and Btfile Name. Sends a TFTP bt request t the NetScaler VIP btained frm the Bt Server Hst Name field in DHCP. The NetScaler makes a lad balancing decisin and subsequently in this case changes the destinatin IP address t that f Prvisining Services/TFTP Server 1 where it directs the bt request. Page 17
Prvisining Services/TFTP Server 1 receives the bt request with the surce IP address f Prvisining Services Client 1 and sends it the initial segment f its btfile Prvisining Services Client 2 Bradcasts a DHCP request which is replied t by the DHCP Server carrying its IP address, Gateway, Bt Server Hst Name, and Btfile Name. Sends a TFTP bt request t the NetScaler VIP via its gateway, the Vyatta ruter. The NetScaler makes a lad balancing decisin and subsequently in this case changes the destinatin IP address t that f Prvisining Services/TFTP Server 2 where it directs the bt request. Prvisining Services/TFTP Server 2 receives the bt request with the surce IP address f Prvisining Services Client 2 and sends it the initial segment f its btfile. Cnfiguratin Screensht Descriptin Cnfigure a Subnet IP (SNIP) Under: >Netwrk>IPs> Select Add frm the bttm menu bar In the Cnfigure IP windw enter the fllwing: IP Address: 192.168.0.94 Select: OK This will be used as the surce IP address fr mnitring the Prvisining Services/TFTP Servers. Page 18
Cnfiguratin Screensht Descriptin Add Prvisining Services Service Grup Under: >Lad Balancing>Service Grups Select Add frm the bttm menu bar In the Create Service Grup windw enter the fllwing: Service Grup Name: Prvisining Services Service Grup Prtcl: ANY Select: pvs-server1 (192.168.0.99) Select the Members tab: Select Server Based Highlight pvs-server1 Prt: * Select Add Highlight pvs-server2 Prt: * Select Add Select the Advanced tab: Select:: Use Surce IP Select Create Select Clse NOTE: The service grup mnitr was left as pingdefault Page 19
Cnfiguratin Screensht Descriptin Add Prvisining Services Virtual Server Under: >Lad Balancing>Services Select Add frm the bttm menu bar In the Create Virtual Server windw, enter the fllwing infrmatin: Name: tftp-any IP Address: 192.168.0.90 Prtcl: ANY Prt: * Select the Service Grups tab: Select: Prvisining Services Service Grup Select the Methd & Persistence tab: Under Persistence Select: SOURCEIP Page 20
Cnfiguratin Screensht Descriptin Cnfigure DHCP Optins Open the Windws Server Manager Select the DHCP Server Rle Cnfigure Scpe 192.168.0.0 crrespnding t netwrk Prvisining Services TFTP2 with Scpe Optins: 066 Bt Server Hst Name = 192.168.0.90 067 Btfile Name = ARDBP32.bin Cnfigure Scpe 10.95.95.0 crrespnding t netwrk Prvisining Services TFTP2 with Scpe Optins: 066 Bt Server Hst Name = 192.168.0.90 067 Btfile Name = ARDBP32.bin Page 21
NetScaler Direct Server Return The netwrk tplgy pertaining t implementatin f this ptin is shwn in the fllwing figure: With this ptin each f the Prvisining Services Client VMs are restarted and fllw the respective paths, utlined abve, sequentially t btain their btfile. Prvisining Services Client 1 Bradcasts a DHCP request which is replied t by the DHCP Server carrying its IP address, Gateway, Bt Server Hst Name, and Btfile Name. Sends a TFTP bt request t the NetScaler VIP, btained frm the Bt Server Hst Name field in DHCP. The NetScaler makes a lad balancing decisin and directs the bt request t Prvisining Services/TFTP Server 1. Hwever in this case it des nt change the IP destinatin t Prvisining Services/TFTP Server 1, rather nly the Page 22
destinatin MAC address is mdified. The frame arrives at Prvisining Services/TFTP Server 1 with the same destinatin IP address as the NetScaler VIP. Prvisining Services/TFTP Server 1 receives the bt request n its external interface and frwards it t its lpback adapter with the same IP address as the NetScaler VIP. It then sends t the surce IP address, which is Prvisining Services Client 1, the initial segment f its btfile. Prvisining Services Client 2 Bradcasts a DHCP request which is replied t by the DHCP Server carrying its IP address, Gateway, Bt Server Hst Name, and Btfile Name. Sends a TFTP bt request t the NetScaler VIP via its gateway, the Vyatta ruter. The NetScaler makes a lad balancing decisin and directs the bt request t Prvisining Services/TFTP Server 2. Hwever in this case it des nt change the IP destinatin t Prvisining Services/TFTP Server 2, rather nly the destinatin mac address is mdified. The frame arrives at Prvisining Services/TFTP Server 2 with the same destinatin IP address as the NetScaler VIP. Prvisining Services/TFTP Server 2 receives the bt request n its external interface and frwards it t its lpback adapter with the same IP address as the NetScaler VIP. It then sends t the surce IP address, which is Prvisining Services Client 2, the initial segment f its btfile. Page 23
Cnfiguratin f the DSR methd is similar t the cnfiguratin fr USIP, yet requires the fllwing changes t the NetScaler cnfiguratin: Base Cnfiguratin Screensht Descriptin MAC Based Redirectin Mde Under: >System>Lad Balancing>Virtual Servers> Highlight the tftp-any Virtual Server Select: Open Select: Advanced TAB Select: MAC Based next t Redirectin Mde Select: Ok Cnfiguratin f the DSR methd als requires cnfiguring a lpback n each Prvisining Services/TFTP Server with an IP address which crrespnds t the NetScaler VIP and setting the TFTP service t listen n that lpback. Instructins are included fr MS Windws Servers nly: Base Cnfiguratin Screensht Descriptin Add MS Lpback adaptr t TFTP servers Fr bth Prvisining Services/TFTP Server 1 & 2: Frm the Windws Start buttn: Right-click: Cmputer Select: Prperties Select: Device Manager Right-click: <Cmputer Name> Select: Add Legacy Hardware Click: Next Select: Install the hardware I manually select frm a list Click: Next Select: Netwrk Adapters Click: Next Select: Micrsft Select: Micrsft Lpback Adapter Click: Next twice Click: Finish Page 24
Base Cnfiguratin Screensht Descriptin Add VIP IP address t MS Lpback adaptr Fr bth Prvisining Services/TFTP Server 1 & 2: Frm the Windws Start buttn: Select: Cntrl Panel Select: Netwrk and Internet Select: Netwrk and Sharing Center Select: Lcal Area Cnnectin 3 (The lpback being the last added will be the highest number) Select: Prperties Select: Internet Prtcl Versin 4 Select: Prperties Select: Use the fllwing IP address Enter: IP Address: 192.168.0.90 Subnet mask:255.255.255.0 Click: Ok & Clse all ther windws NOTE: It is nt necessary t specify a default gateway. This shuld already be specified n the primary interface as the Vyatta ruter. Page 25
Base Cnfiguratin Screensht Descriptin Cnfigure adapters t send and receive fr lpback This step is necessary in rder t allw the server interfaces t send and receive traffic destine fr the IP addresses f bth the lpback and external interfaces Fr bth Prvisining Services/TFTP Server 1 & 2: Frm the Windws Cmmand prmpt enter: netsh interface ipv4 set interface "Lcal Area Cnnectin" weakhstreceive=enabled set interface "Lcal Area Cnnectin 3" weakhstreceive=enabled set interface "Lcal Area Cnnectin 3" weakhstsend=enabled Fr mre infrmatin see this article n Micrsft TechNet: http://technet.micrsft.cm/enus/magazine/2007.09.cableguy.aspx Page 26
Base Cnfiguratin Screensht Descriptin Bind TFTP Service t Lpback This step is necessary in rder t allw the Prvisining Services/TFTP Servers t receive TFTP requests n the lpback interface. Fr bth Prvisining Services/TFTP Server 1 & 2: Open Windws Explrer: Brwse t C:\Prgram Files\Citrix\Prvisining Services Duble click tftpcpl.cpl Select the TFTP Netwrk TAB Select the lpback 192.168.0.90 Click OK Click Yes t restart the TFTP service T verify pen a DOS prmpt and enter: Netstat na findstr 192.168.0.90:69 The utput shuld reflect the lpback listening n UDP prt 69 Page 27
NetScaler Glbal Server Lad Balancing The netwrk tplgy pertaining t implementatin f this ptin is shwn in the fllwing figure: With this ptin each f the Prvisining Services Client VMs are restarted and fllw the respective paths, utlined abve, sequentially t btain their btfile. Prvisining Services Client 1 Bradcasts a DHCP request, which is replied t by the DHCP Server carrying its IP address, Gateway, Bt Server Hst Name, and Btfile Name. Attempts t reslve the Bt Server Hst Name tftp frm the DNS Server. The DNS Server is cnfigured with an alias fr tftp that references the NetScaler Authritative DNS (ADNS) listener. A DNS name query is frwarded t NetScaler1, frm the DNS server, n behalf f Prvisining Services Client 1. Once the NetScaler1 ADNS prcess receives the request it queries the GSLB Page 28
prcess dynamically and based n the least cnnected algrithm returns the Prvisining Services/TFTP Server 1 in the DNS reply. The DNS Server sends this DNS reply t Prvisining Services Client 1 Sends a TFTP bt request t the Prvisining Services/TFTP Server 1 and it initiates TFTP transfer f the btfile t the Prvisining Services Client 1. Prvisining Services Client 2 Bradcasts a DHCP request, which is replied t by the DHCP Server carrying its IP address, Gateway, Bt Server Hst Name, and Btfile Name. Attempts t reslve the Bt Server Hst Name tftp frm the DNS Server. The DNS Server is cnfigured with an alias fr tftp that references the NetScaler Authritative DNS (ADNS) listener. A DNS name query is frwarded t NetScaler2, frm the DNS server, n behalf f Prvisining Services Client 2. Once the NetScaler2 ADNS prcess receives the request it queries the GSLB prcess dynamically and based n the least cnnected algrithm returns the Prvisining Services/TFTP Server 2 in the DNS reply. The DNS Server sends this DNS reply t Prvisining Services Client 2 Sends a TFTP bt request t the Prvisining Services/TFTP Server 2 and it initiates TFTP transfer f the btfile t the Prvisining Services Client 2. Page 29
The NetScaler - GSLB methd is cnfigured as fllws: Cnfiguratin Screensht Descriptin Enable GSLB Service Under: >System>Settings>Cnfigure Advanced Features Cnfigure the ADNS Service Under: >Lad Balancing> Services> Select Add frm the bttm menu bar In the Cnfigure IP windw enter the fllwing: Service Name: ADNS Prtcl: ADNS Server: 192.168.0.94 Prt: 53 Select Create Select Clse Add GSLB Site Under: >GSLB>Sites Site1 Prvisining Services TFTP Select Add frm the bttm menu bar In the Create GSLB site windw enter the fllwing: Name: Prvisining Services - TFTP Site Type: LOCAL Site IP Address: 192.168.0.94 Select Create Page 30
Cnfiguratin Screensht Descriptin Add GSLB Services Under: >GSLB>Services Prvisining Services TFTP SERVER1 Select Add frm the bttm menu bar In the Create GSLB Service windw enter the fllwing: Service Name: Prvisining Services TFTP SERVER1 Server Name: pvs-server1 Service Type: UDP Prt: 69 Select Create Prvisining Services TFTP SERVER2 Again In the Create GSLB Service windw enter the fllwing: Service Name: Prvisining Services TFTP SERVER2 Server Name: pvs-server2 Service Type: UDP Prt: 69 Select Create Select Clse Page 31
Cnfiguratin Screensht Descriptin Add GSLB Virtual Server Under: >GSLB>Virtual Servers Select Add frm the bttm menu bar In the Create GSLB Virtual Server windw Under the Services Tab: Select: Prvisining Services TFTP SERVER1 Select: Prvisining Services TFTP SERVER2 NOTE: The Effective State will shw DOWN the state f the services is nt being cmmunicated via MEP since a remte site is nt being used. Under the Dmain Tab: Select Add Enter Dmain Name: tftp.gslb.pvslab.cm Select Create Select Clse Page 32
Cnfiguratin Screensht Descriptin Update DHCP Optins Open the Windws Server Manager Select the DHCP Server Rle Cnfigure Scpe 192.168.0.0 crrespnding t netwrk Prvisining Services TFTP2 with Scpe Optins: 066 Bt Server Hst Name = tftp.pvslab.cm 067 Btfile Name = ARDBP32.bin Cnfigure Scpe 10.95.95.0 crrespnding t netwrk Prvisining Services TFTP2 with Scpe Optins: 066 Bt Server Hst Name = tftp.pvslab.cm 067 Btfile Name = ARDBP32.bin Page 33
With the TFTP GSLB ptin the DNS server must be cnfigured with a Name Server fr the NetScaler ADNS service, a gslb subdmain, and an alias directing queries fr the tftp name t it. Cnfiguratin Screensht Descriptin Cnfigure DNS Server Open the Windws Server Manager Select the DNS Server Rle Right-click n the pvslab.cm dmain entry and select "New Delegatin" Click: Next Enter: gslb Click: Next Select Add Name Server Name: ns1 Select: <Click here t add an IP Address> IP: 192.168.0.94 Click: OK Click: Next Click: Finish Right-click n the pvslab.cm dmain entry and select "New Alias (CNAME)" Alias Name: tftp FQDN: tftp.gslb.pvslab.cm Click: Ok See Appendix B - Reference Dcumentatin fr mre infrmatin regarding installatin Page 34
Appendix A Envirnment Details Cmpnent Details Prvisining Services Versin 5.6.2 XenServer Versin 5.6_2 NetScaler VPX Versin 9.3-51.5 Windws Server Versin 2008 R2 Vyatta Ruter Versin 2.6.35-1 Appendix B Reference Dcumentatin Hw t Add DHCP PXE Optins t Micrsft DHCP Server http://supprt.citrix.cm/article/ctx115094 Requirements fr Internet Hsts -- Cmmunicatin Layers http://datatracker.ietf.rg/dc/rfc1122/?include_text=1 The Cable Guy: Strng and Weak Hst Mdels http://technet.micrsft.cm/en-us/magazine/2007.09.cableguy.aspx Prvisining Server High Availability Cnsideratins http://supprt.citrix.cm/servlet/kbservlet/dwnlad/18737-102- 445549/Prvisining_Server_High_Availability_Cnsideratins2.pdf Installing Windws Server 2008 DHCP Server http://www.windwsnetwrking.cm/articles_tutrials/hw-t-install-cnfigure- Windws-Server-2008-DHCP-Server.html Hw t Add DHCP PXE Optins t Micrsft DHCP Server http://supprt.citrix.cm/article/ctx115094 Using Prvisining Services Bt Device Manger with XenDesktp and XenServer http://blgs.citrix.cm/2009/02/25/using-pvs-bt-device-manger-with- XenDesktp-and-XenServer/ Using the Manage Bt Devices Utility http://supprt.citrix.cm/prddcs/tpic/prvisining-56/pvs-bt-devicesutility.html Vyatta Ruter Quick Start Guide http://www.vyatta.cm/sites/vyatta.cm/files/pdfs/vyatta_quickstart_r6.1_v02_ 1.pdf Citrix XenServer - Quick Start Guide Page 35
http://dcs.vmd.citrix.cm/xenserver/5.6.0fp1/1.0/en_gb/quickstartguide_basi cversin.html Citrix NetScaler VPX Getting Started Guide - Release 9.3 http://supprt.citrix.cm/article/ctx128668 Prvisining Server and Citrix License Server Interactin FAQ http://supprt.citrix.cm/article/ctx117378 Redundancy and Scalability fr TFTP using NetScaler Direct Server Return http://blgs.citrix.cm/2010/11/11/redundancy-and-scalability-fr-tftp-using- NetScaler-direct-server-return/ Cnfiguring Lad Balancing in Direct Server Return Mde http://supprt.citrix.cm/prddcs/tpic/netscaler-lad-balancing-93/ns-lbusecases-dsrmde-cn.html#ns-lb-usecases-dsrmde-cn Lad Balancing TFTP Anything But Trivial http://blgs.citrix.cm/2011/05/02/lad-balancing-tftp-anything-but-trivial/ Citrix NetScaler Netwrking Guide http://supprt.citrix.cm/servlet/kbservlet/dwnlad/27520-102- 659875/NetScaler-Netwrking-Guide.pdf Using a NetScaler Appliance in the Use Surce IP Mde http://supprt.citrix.cm/article/ctx117346 Des Use Surce IP Mde Wrk in a NetScaler One-arm Mde Deplyment? http://supprt.citrix.cm/article/ctx110459 FAQ: The USIP Address Mde f the NetScaler Appliance http://supprt.citrix.cm/article/ctx121974 Hw t Lad Balance Trivial File Transfer Prtcl Servers http://supprt.citrix.cm/article/ctx116337 Hw t Cnfigure the Direct Server Return n a NetScaler Appliance http://supprt.citrix.cm/article/ctx110501 High Availability fr Desktp Virtualizatin http://supprt.citrix.cm/servlet/kbservlet/dwnlad/21773-102- 650177/XD%20-%20High%20Availability%20-%20Implementatin%20Guide.pdf Hw t Add DHCP PXE Optins t Micrsft DHCP Server http://supprt.citrix.cm/article/ctx115094 Page 36
Revisin Histry Revisin Change Descriptin Updated By Date 1.0 Dcument cmplete Matt Brks Principal Cnsultant December 1, 2011 Nichlas Rintalan Sr. Architect Abut Citrix Citrix Systems, Inc. (NASDAQ:CTXS) is the leading prvider f virtualizatin, netwrking and sftware as a service technlgies fr mre than 230,000 rganizatins wrldwide. It s Citrix Delivery Center, Citrix Clud Center (C3) and Citrix Online Services prduct families radically simplify cmputing fr millins f users, delivering applicatins as an n-demand service t any user, in any lcatin n any device. Citrix custmers include the wrld s largest Internet cmpanies, 99 percent f Frtune Glbal 500 enterprises, and hundreds f thusands f small businesses and prsumers wrldwide. Citrix partners with ver 10,000 cmpanies wrldwide in mre than 100 cuntries. Funded in 1989, annual revenue in 2010 was $1.9 billin. 2011 Citrix Systems, Inc. All rights reserved. Citrix, Access Gateway, Branch Repeater, Citrix Repeater, HDX, XenServer, XenApp, XenDesktp and Citrix Delivery Center are trademarks f Citrix Systems, Inc. and/r ne r mre f its subsidiaries, and may be registered in the United States Patent and Trademark Office and in ther cuntries. All ther trademarks and registered trademarks are prperty f their respective wners. Page 37