I am writing an auto-registration service that will allow machines to add themselves to the Load Balancer. Due to the transactional nature of this process, I am never quite sure when everyone is registered. If a synch call is blocking to the point where I would have wait 2-10 seconds for the synch to complete before the transaction could complete. It would render the service unusable perfomance wise. Is the sych call non-blocking? Can I run it on the through a cron job on the LB without adversley affecting performance? Thanks in advance, Justin

I'm not quite sure I understand what you're trying to do. By "synch", are you referring to configsync'ing or failover? Are you saying that once the new servers are added to the active BIG-IP, that you'd like to new configuration to get synched to the standby unit before doing something else? Please clarify. Configsync is a "semi" blocking call, meaning that iControl will wait for as long as it can for configsync status before returning, but will cause an exception if the wait is longer than the webserver's response timeout. Configsync from the CLI/GUI is also a blocking call. Due to the nature of configuration synchronization, this process can't be non-blocking since we need to know that every aspect of configsync is successful or not synchronously, before something else that depends on the configuration is performed. Loc

Config sync'ing. I would like to have the two synched somehow. I know that there is a call from iControl that will do it. However, what I am working is transactional, so it must synch before moving on to another task if I am to use that mechanism for synchronization. If I waited for it or the timeout, that kind of latency would really make this service unusable. I suppose you have answered my question. I really need to find another way to synchronize. Can I use a cron job? Could I do it with a monitor? Thanks in advance, Justin

Although you can configure a cron job to run configsync in the background, in your transactional code elsewhere, you still won't have any feedback that the configsync process is successful or not (unless you don't care if the new configuration actually can load on the peer machine). As you may have known, configsync is an involved process in which configuration from the source box must be packaged up and transferred to the peer box, and the new configuration must be loaded successfully on the peer. If you have a large configuration set with 1000s of VSes, pools and servers..., this may take some time to finish. It's the reason configsync is not seen as something that is done on a regular basis. Even when new servers are added/removed from a LB pool, typically configsync should only be done when everything is stabilized. The CLI, GUI, and iControl all use the same mechanism to configsync, so your cron job (which will likely use a CLI command) will also take approx the same amount of time to finish. In the next release of BIGIP, we'll have an auto-configsync feature, in which if enabled, configsync will be automatically done when it detects that something has changed. Thanks, Loc

First off, I realize the age of this topic, but I had to respond. This is indeed my first post on devcentral. My question is in regards to the 'auto config sync' option on the new release. My concern is for administrators who make changes to the configuration quite frequently, and whether or not the automatic nature of this synchronization will account for that. For example, if I remove a server for 10 seconds from a pool, is the automatic sync going to kick off twice? Thanks for the time, Billy

The "auto-configsync" feature will not start configsync'ing right away when configuration changes. There's a timeout period for the last configuration change to become "stable" before this feature kicks in. This timeout will be a configurable parameter. Regards, Loc

Best Practice for Sync Between Primary and Failover

38 Replies

orangepeelbeef_
Nimbostratus
Jan 22, 2009
I'm running 9.4.5 on BIGIP1500's so I doubt it's the hardware.
micah_64538
Nimbostratus
Feb 02, 2009
any update/solution from F5 on this?
Ciro_Deng_14211
Nimbostratus
Feb 03, 2009
I get a solution from F5 support.

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

Try setting the "-processes" to "2". You'll need to restart httpd after making this change.

All in one command

sed -ie 's/-processes [0-9]\+/-processes 2/g' /etc/httpd/conf/httpd.conf; bigstart restart httpd

If you can not restart httpd, restart bigip directly!

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

I tested this, it works in BigIP6900 OS 9.4.
micah_64538
Nimbostratus
Feb 03, 2009
Great! Works exactly as expected now.
Don_MacVittie_1
Historic F5 Account
Feb 03, 2009
We were just discussing this thread and digging in with support to find out if your problems were resolved - thanks cdtdx for posting the response, saves us from hunting it down!

Don.
orangepeelbeef_
Nimbostratus
Feb 04, 2009
solved it for me as well

Thanks guys =)
hellhammer_3588
Nimbostratus
Feb 05, 2009
Yes. Changing "-processes 2" will make it work. I've tested it successfully in my BIGIIP6900 9.4.6.

I got confirmed from F5 that they found this problem since 9.4.x OS. btw, I didn't meet this problem before when running 9.3.x.

I guess they may release a hotfix or sth. to fix it.
David_Karakas
Employee
Feb 17, 2009
This issue is being tracked by F5 Product Development as CR116460 scheduled to be fixed in a future release. An AskF5 solution will be published to discuss this issue and workaround.
gerald_wegener_
Nimbostratus
Feb 27, 2009

I have this problem using pyControl when I upgraded from 9.3.1 to 9.4.5. I would get no response using either of the pyControl commands below for config sync. After I ran this if I then tried to do a manual config sync that would fail as well and I was forced to reboot the box.

After I found this thread I tried the recommended command on both the active and the standby box but the problem persisted with 9.4.5. I then upgraded to 9.4.6, applied the commands again but I still have the same problem.

Any idea's on how this can be fixed?

These are the commands I'm using running 9.4.6(both fail)

Thank You.

b.System_ConfigSync.synchronize_configuration(sync_flag = 'CONFIGSYNC_ALL')

b.System_ConfigSync.synchronize_configuration(sync_flag = 'CONFIGSYNC_BASIC')
Joe_Pruitt
Mar 09, 2009
As I just posted in another forum thread(Click here), modifying the core webserver configuration can have unwanted side effects and F5 does not endorse this change. Several components such as System locking and Partition settings are stored in-process. When you increase the number of processes, this breaks the functionality of the above features. Also, by adding another iControlPortal process, you are also effectively doubling the memory needed to run iControl.

This really needs to be sent to F5 Product Support and get Development to get a better fix for this problem that does not cause unwanted side effects.

-Joe