eth202: introduction to web switching and load balancingserveriron adx(config-rs-r5)# server...
TRANSCRIPT
Introduction to ServerIron ADX Application
Switching and Load Balancing
Module 5: Server Load Balancing (SLB)
Revision 0310
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 2
Objectives
Upon completion of this module the student will be able to:
– Describe Source-NAT
– Describe Hot Standby Redundancy
– Define Direct Server Return (DSR)
– Define Active Standby Redundancy
– Define Remote Servers
– Describe Primary and Backups
Source-NAT
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 4
The Problem: ServerIron ADX in a Multinetted
Network Without Source-NAT
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 5
The Solution: ServerIron ADX in a Multinetted
Network With Source-NAT
ServerIron ADX can operate in a multinetted environment
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 6
Source NAT configured on a per real server basis (local)
• Source NAT under individual real server‟s is recommended
Source NAT can be configured on a global level
Source-NAT Example
server source-nat
server source-ip 10.10.10.50 255.255.255.0 10.1.1.1
!
server real rs1 10.10.10.201
source-nat
port http
port http url “HEAD /”
!
server real rs2 10.10.10.202
source-nat
port http
port http url “HEAD /”
!
server virtual vip 169.144.10.100
port http
bind http rs1 http rs2 http
bind http rs4 http
Use Source-NAT to reach these servers
Source-NAT
Lab 5-1
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 8
Lab 5-1:Source NAT
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 9
Lab 5-1 Review: Source-NAT Packet Walk
Hot-Standby Redundancy
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 11
Hot-Standby Redundancy (1 of 3)
Dedicated Synchronization Link
– State tables are synchronized through this link without using bandwidth on the data path
– Detects failure of the “Active” switch within 1 sec
– In the event of a Sync Link failure, the data path is checked to see if the “Active” switch is still online
Requires a common Layer 2 Domain:
– Switches & Real Servers
Traffic is “heard” by both Switches
– “Active” Switch switches traffic from clients to the appropriate Physical Servers
– “Standby” Switch also builds Network Address Translation (NAT) table, but passes no traffic while in Standby-mode
Both Switches are configured with the same MAC address (One or the other switch‟s lowest MAC)
– When the “Standby” takes over, no re-ARP is needed
– Client community still uses mapping of Virtual IP to locally administered MAC address being advertised
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 12
Hot-Standby Redundancy (2 of 3)
When an “Active” Switch fails…
– Standby switch listens through
sync link to detect when the
other side is no longer alive
– Session information is kept in
sync until the “Active” fails to
communicate with the “Standby”
– Data path is also checked (via
ping) to see if it was merely a
failure in the Sync link
“Standby” switch becomes “Active”
Client to server connections are preserved across
the “Active” to “Standby” failover
Any lost packet retries are re-initiated by the
client/server
No re-ARPing is required by clients or downstream
routers
– Both switches are configured with the same
Locally Administered Address (LAA) MAC
e.g. 02-00-0c-76-d8-88
During the failure, the “Standby” switch now
operates as the “Active” switch and switches traffic
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 13
Hot-Standby Redundancy (3 of 3)
The failed switch can be swapped out and replaced while server
farm is operational
– The new switch takes the “Standby” role upon detection of the
“Active” switch
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 14
On both ADX’s:
ADX(config)# server backup ethernet 1 00e0.5202.85ae
ADX(config-vlan-22)# no spanning-tree
This is the port that the
„heart beat‟ cable is connected to.
This is a MAC address of port one on one of the
ServerIron ADXs. Enter this SAME MAC address on both
ServerIron ADXs. Use the command “show interface brief”
to display the MAC addresses.
Hot-Standby Redundancy Configuration
ADX(config)# server backup-preference 5
The ServerIron ADX with this command will always be the active ServerIron ADX. The 5 is the time it will take
for the this ServerIron ADX to become active again in minutes, 5 is the minimum value.
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 15
Synchronization of Configurations
Configuration ServerIron ADX A:
ServerIron ADXA# configure terminal
ServerIron ADXA(config)# config-sync sender e 1 mac 00e0.5201.0c72 vlan 22
Configuration ServerIron ADX B:
ServerIron ADXB# configure terminal
ServerIron ADXB(config)# config-sync receiver e 1 mac 00e0.5202.020a vlan 22
Initiating and and Ending the Synchronization:
ServerIron ADXA(config)# confic-sync slb
Hot-Standby Redundancy
Lab 5-2
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 17
Lab 5-2: Hot-Standby Redundancy
Direct Server Return (DSR)
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 19
Direct Server Return (DSR) Overview
Responses from the Real Servers are sent directly back to clients
via the router
Optimal for high-bandwidth, low latency SLB applications
Traffic Flow: a. Small requests are sent from client to the Server Farm (typically 64-128 byte)
b. The small requests can result in large frames being sent directly back to the client
– Large GIF/JPEG images – Large File transfers – Maximize the throughput back to the users
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 20
DSR Configuration
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 21
DSR in Action
Direct Server Return (DSR)
Lab 5-3
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 23
Lab 5-3: Direct Server Return (DSR)
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 24
Lab 5-3 Review: DSR Packet Walk
Active-Standby Redundancy
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 26
Symmetric Server Load Balancing Active-Standby
Dual ADXs share active loads
Both ADXs are “Active” and continue to be a “backup” for each other in
case the other fails
Supports more connections, more throughput
Same application/port cannot be mapped to 2 or more VIPs
– If necessary create an alias port
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 27
Active-Standby SLB
server virtual vip2 169.144.10.200
• port http
• bind http RS1 2000 RS2 2000
• no port http translate
server virtual vip1 169.144.10.100
• port http
• bind http RS1 http RS2 http
Steps to configure VIP 1 and VIP 2 on both ADX-A and ADX-B
Active-Standby Redundancy
Lab 5-4
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 29
Lab 5-4: Active-Standby Redundancy
Remote Server
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 31
Remote Server Farms
Remote Server Farms can be:
– on a different subnet
– located in a different facility (disaster recovery)
– used as BACKUP of last resort (i.e. used only if all of the Local Servers are unavailable)
– specify Source-NAT so the traffic back to the client appears to have returned from the
VIP
– cannot configure DSR on a remote server
Remote Server
Lab 5-5
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 33
Lab 5-5:Remote Server
Other Features
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 35
Active-Active Symmetric Server Load Balancing
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 36
Primary and Backup Servers
Primary/Backup – Local or Remote
Servers that are locally attached to the ServerIron ADX (not separated by one or
more router hops) are local servers.
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 37
Primary/Backup Server Configuration Example
ServerIron ADX(config)# server real-name R3 10.10.10.203
ServerIron ADX(config-rs-R3)# backup
ServerIron ADX(config-rs-R3)# port http
ServerIron ADX(config-rs-R3)# exit
ServerIron ADX(config)# server remote-name R5 198.10.10.50
ServerIron ADX(config-rs-R5)# backup
ServerIron ADX(config-rs-R5)# port http
ServerIron ADX(config)# server real-name R1 10.10.10.201
ServerIron ADX(config-rs-R1)# port http
ServerIron ADX(config-rs-R1)# exit
ServerIron ADX(config)# server remote-name R4 198.10.10.40
ServerIron ADX(config-rs-R4)# port http
ServerIron ADX(config-rs-R4)# exit
Primary Servers
ServerIron ADX(config-rs-R5)# server virtual-name VIP1 198.10.10.100
ServerIron ADX(config-vs-VIP1)# port http lb-pri-servers
ServerIron ADX(config-vs-VIP1)# bind http R2 http R3 http R4 http R5 http
Backup Servers
VIP
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 38
Clone Real Server Configuration
Auto binding of cloned server to VIP
ServerIron ADX(config)# server real RS1 1.2.3.4
ServerIron ADX(config-rs-rs1)# clone-server RS2 5.6.7.8
© 2009 Brocade Communications Systems, Inc.
All Rights Reserved. 39
Session Persistence: Sticky vs. Concurrent
End of Module 5: Server Load Balancing
Revision 0310