Whiteboard

DC Post of the Week - Graceful Server Connection Draining

DevCentral TV — Thu, 07 Aug 2008 19:39:41 GMT

In this week’s Post of the Week, Joe talks about using iControl to automate the process of bleeding off connections from a server, then bringing it all the way down once all connections have closed. Thanks to poster nevot from Spain for a great question demonstrating how iControl can help automate a common change control function.

BTW, sorry for the background noise. Remind me to shut down my BIG-IP next time B-).

Here's a link to the post: iControl graceful stop node.

Technorati Tags: F5, DevCentral, Post of the Week, DCTVPOTW, iControl, provisioning, Joe Pruitt

DC Post of the Week - iControl for SQL Server Triggered Failover

DevCentral TV — Thu, 31 Jul 2008 18:53:42 GMT

This week, Colin & Deb dig into an interesting scenario presented by poster dchenna requesting feedback on the best way to quickly and reliably swap out the active database server for certain operational & maintenance events. After reviewing the relative merits of a the suggestions and warnings offered by several respondents, it seems the best solution is an iControl call to modify the pool configuration when required.

Here’s the post: F5 to load balance MS Sql Servers

Technorati Tags: F5, DevCentral Daily, Post of the Week, DCTVPOTW, SQL Server, iControl, Deb Allen, Colin Walker

DC Post of the Week - Finding Latency in Multi-hop Connections

DevCentral TV — Thu, 24 Jul 2008 20:09:25 GMT

In this week’s Post of the Week, Colin & Deb take a look at a question from poster shayne.rinne, and offer some suggestions for determining the source of additional latency when a second virtual server is added into the path between a client, a reverse proxy, and the origin server..

Here's the post: VIP to VIP communication

Technorati Tags: F5, DevCentral, Post of the Week, DCTVPOTW, Latency, Deb Allen, Colin Walker

DC Post of the Week - Application Health Monitors: Alternate Ports

DevCentral TV — Thu, 17 Jul 2008 08:08:06 GMT

In this week’s Post of the Week, Deb Allen talks about a forum post by user sojourner9 regarding configuring an application health monitor to check a port besides the one configured for a pool member.

Technorati Tags: F5, DevCentral, Post of the Week, DCTVPOTW, Health Monitors, Deb Allen

DC Post of the Week - Application Health Monitors : Response Strings

DevCentral TV — Thu, 10 Jul 2008 16:04:13 GMT

In this week’s Post of the Week, Deb Allen talks about a forum post by DevCentral user michael.trott about setting up an appropriate Response string to mark a server down if it returns a “200 OK” along with a detailed error page.

Technorati Tags: F5, DevCentral, Post of the Week, DCTVPOTW, Health Monitors, Deb Allen

Share this post :

DC Post of the Week - Persisting Across Virtual Servers

DevCentral TV — Thu, 03 Jul 2008 22:20:56 GMT

This week’s Post of the Week is based on a post by sosa123, entitled F5 and RTCP, looking for guidance in configuring persistence to the same servers across 2 different virtual servers. Deb Allen and Colin Walker go through the steps required to support this commonly requested load balancing scenario.

Technorati Tags: F5, DevCentral, DCTVPOTW, Post of the Week, RTCP, Persistence, Load Balancing, Colin Walker, Deb Allen

DC Post of the Week - Route Health Injection

DevCentral TV — Thu, 26 Jun 2008 19:23:12 GMT

This week’s Post of the Week is based on the post GTM and IP selection by poster cknail. He was looking for a solution to hand out the same IP address for LTM virtual servers in different data centers, in support of devices that don’t honor the short TTL asserted by GTM. After an interesting discussion by several F5 engineers regarding the interplay between LTM and GTM regarding monitoring VS status, it turns out that the best solution is LTM only with the ARM (Advanced Routing Module) licensed and configured to provide Route Health Injection based on LTM monitoring results for virtual server peers on a BGP or OSPF peering network.

Technorati Tags: F5, DevCentral, DCTVPOTW, Post of the Week, GTM, ARM, BGP, OSPF

Election Hash Load Balancing

DevCentral TV — Thu, 26 Jun 2008 16:51:01 GMT

F5 Solutions Architect Nathan McMahon explains Election Hash Load Balancing And Persistence (find the iRule in the codeshare here). He developed this Election Hash solution to address the limitations of the Cache Array Routing Protocol, and it provides a nice alternative to any typical hash solution that are vulnerable to re-factoring on changes to the server pool. The complete solution is written up here: Hash Load Balancing and Persistence on BIG-IP LTM

This solution was brought to you by the iRules commands: md5, HTTP::uri, and active_members

Technorati Tags: F5, DevCentral, iRules, Election Hash, Load Balancing, Nathan McMahon

Universal Persistence with SSL Offload

DevCentral TV — Wed, 25 Jun 2008 16:25:25 GMT

F5 Field Systems Engineer Christopher Schaefer sits down with Colin & Deb to explore an interesting iRules solution: Persistence for mobile devices running a proprietary stateful TCP application while roaming across cell towers mid-session. In the absence of a consistent IP address or any identifying header information, Chris discovered the client mobile ID embedded in the binary data of the traffic stream, and built a custom Universal Persistence solution. This solution was only possible because of the SSL offload capability of LTM, which allows LTM to decrypt the traffic before examining and acting upon it.

This solution was brought to you by the iRule commands: persist , TCP::collect, and TCP::payload, and the Tcl command binary

Technorati Tags: F5, DevCentral, Persistence, SSL, LTM, Christopher Schaefer

Active-Active Database Load Balancing

DevCentral TV — Thu, 19 Jun 2008 15:16:43 GMT

F5 Field Systems Engineer Patrick Chang explains an iRules solution that supports 2 active database instances in different data centers behind a web application. The goal is to provide the optimal user experience by load balancing requests for both the web/application tier and the database tier to a local data center whenever possible. Since cross-data center database replication takes approximately 20 seconds, one instance is preferred for database writes, and an iRule that reads and inserts time-stamped cookies reliably directs traffic to the closest database instance when possible, and to the remote instance only when necessary to maintain session integrity.

This solution was brought to you by the iRule commands: HTTP::cookie, HTTP::uri, and HTTP::method

Technorati Tags: F5, DevCentral, iRules, Database, Patrick Chang