F5的负载均衡和监控策略配置

1、Load Balancing,Static Methods Round Robin (RR) Ratio (Weighted Round Robin) Distributes connections in a RR fashion for members/nodes whose ratio has not been met Dynamic Methods* Least Connections Fewest connections at the moment the load balancing decision is being made Fastest v9.0-v9.3.1 not imp

2、lemented, defaults to round robin (issued tracked in CR22586) v9.4 and higher base on outstanding Layer 7 requests and open L4 connections Both a TCP and Layer 7 profiles are required If there is no Layer 7 profile on the virtual server, defaults to least connections Observed Calculates a ratio each

3、 second for each member based on the number of layer 4 connections and then load balances based on that ratio Predictive Differs from Observed mode in that it looks at the change between the previous connection counts and the current connection counts Dynamic Ratio Dynamically weights servers based

4、on results SNMP/WMI queries Requires SNMP_DCA , SNMP_Base or WMI monitoring of pool,Load Balancing Methods,*SOL6406 - Change in Behavior: Fastest, Observed, and Predictive load balancing modes,Load Balancing,Load balancing a service (member) versus IP address (node) Member - look only at the statist

5、ics of the targeted pool Node - look at all pools a containing the IP addresses (nodes) of the targeted pool,http_vs :80,secure_vs :443,Request,Which pool member has the fewest connections,Which node has the fewest connections,Least Connections (member),Least Connections (Node),Server_

6、A 00,Server_B 01,605 conns,210 conns,web_pool Priority = 5 Activation 2,Load Balancing,Two Basic Pool Failure Mechanisms Fallback Host (for HTTP and HTTPS applications) Is the server of last resort if all pool members are unavailable HTTP redirect (http 302) is returned to client Confi

7、gured in the HTTP profile, the fallback host is not monitored Priority Group Activation Ability to dynamically pull in new members into the pool Lower priority groups are pull into higher priority groups All members of a priority group are pull in a together,ftp_pool Priority = 5 Activation 3,Backup

8、 Servers Running WWW and FTP Priority = 1,Default Gateway Pool,Default Gateway Pools,Load balancing doesnt have to just be inbound,def_gw_vs /0 auto lasthop,VLAN isp69 Network /24 SNATpool 0-29,VLAN isp205 Network /24 SNATpool 0-29,Which gateway is best?,69.9

9、.9.1,,Internet,IP 9 GW ,VLAN Internal SelfIP ,Load Balancing,LAB 3 Load Balancing Ratio Lab Priority Group Lab,Monitors,Monitors,A monitor is a test of a specific application, for an expected response, within a given time. The administrator can configure the inter

10、val between checks and when the monitor times out. Interval is the time between each check Timeout is the length of time for a successful check to be received before the node is marked down The LTM can use composite monitors, so multiple checks can be applied! All or some of the monitors can be used

11、 to determine member status Monitors can also use reverse logic,Monitors (cont.),Node Checks Determine availability of all services for a particular node Example: ICMP check, is the node pingable When check fails, node is pull from all pools it has membership in Service Checks Checks connectivity to

12、 services/ports Example: HTTP check, can port 80 be opened Content Checks Queries the service and checks the contents of the query Example: HTTP GET /, is the page returning with correct content Content checks can involve username and passwords Path Checks Are transparent monitors checking through d

13、evices to verify a path exists Or used to monitor applications outside the pool, that are required for the pool to function Interactive Checks Custom scripts can be created to interact with application Examples are in /usr/bin/monitors and ,Monitor Types in GUI (partial list),Simple monitors ICMP ch

14、ecks the status of a node, using Internet Control Message Protocol (ICMP). Gateway ICMP checks nodes in a pool that implements gateway failsafe for high availability. TCP Echo checks the status of a node, using Transmission Control Protocol (TCP). Extended Content Verification (ECV) monitors TCP ver

15、ifies the Transmission Control Protocol (TCP) service by attempting to receive specific content from a node. HTTP verifies the Hypertext Transfer Protocol (HTTP) service by attempting to receive specific content from a web page. HTTPS verifies the Hypertext Transfer Protocol Secure (HTTPS) service b

16、y attempting to receive specific content from a web page protected by Secure Socket Layer (SSL) security. Extended Application Verification (EAV) monitors External allows users to monitor services using their own programs. FTP verifies the File Transfer Protocol (FTP) service by attempting to downlo

17、ad a specific file to the /var/tmp directory on an LTM system. Once downloaded successfully, the file is notsaved. IMAP Verifies the Internet Message Access Protocol (IMAP) by attempting to open a specified mail folder on a server. This monitor is similar to the pop3 monitor. LDAP Verifies the Light

18、weight Directory Access Protocol (LDAP) service by attempting to authenticate the specified user. MSSQL Verifies Microsoft Windows SQL-based services. NNTP Verifies the Usenet News protocol (NNTP) service by attempting to retrieve a newsgroup identification string from the server.,Monitor Types,EAV

19、monitors (continued) Oracle Verifies services based on Oracle by attempting to perform an Oracle login to a service. POP3 Verifies the Post Office Protocol (pop3) service by attempting to connect to a pool, pool member, or node, log on as the specified user, and log off. RADIUS verifies the Remote A

20、ccess Dial-in User Service (RADIUS) service by attempting to authenticate the specified user. Real Server checks the performance of a pool, pool member, or node that is running the RealServer data collection agent, and then dynamically load balances traffic accordingly. SIP checks the status of Sess

21、ion Initiation Protocol (SIP) Call-ID services on a device. The SIP protocol enables real-time messaging, voice, data, and video. SMTP checks the status of a pool, pool member, or node by issuing standard Simple Mail Transport Protocol (SMTP) commands. SNMP DCA Checks the current CPU, memory, and di

22、sk usage of a pool, pool member, or node that is running an SNMP data collection agent, and then dynamically load balances traffic accordingly. SNMP DCA Base Checks the current user usage of a pool, pool member, or node that is running an SNMP data collection agent, and then dynamically load balance

23、s traffic accordingly. The way that you configure the monitor settings determines the data that the LTM system collects. SOAP Tests a Web service based on the Simple Object Access Protocol (SOAP). UDP Verifies the User Datagram Protocol (UDP) service by attempting to send UDP packets to a pool, pool

24、 member, or node and receiving a reply. WMI Checks the performance of a pool, pool member, or node that is running the Windows Management Infrastructure (WMI) data collection agent and then dynamically load balances traffic accordingly.,Monitor Status Reporting,Statuses are base on monitor response

25、and object hierarchy. The Virtual Server status is affected by the status of the Pool The Pool status is affected by the status of Pool Members A Pool Member is affected by the status of the node that supports it What happens when a monitor fails When a monitor check fails the member becomes suspect LTM sends no NEW connections to the member existing connections are maintained If there is a successful check before the timeout value is reached things continue normally If the monitor failures exceed the timeout value the member i