Category Archives: Network Load Balancing

Kemp LoadMaster template import issue: Command serverinit needs 1 parameter(s)

Posted on by
Reply

Introduction

The error Kemp LoadMaster template import issue: Command serverinit needs 1 parameter(s) was encounter during a migration project I was involved in recnetly. Recently. The job was to migrate the virtual services of an aging Kemp LoadMaster HA solution (LM-2200, 32 bit) to newer and more capable versions (running 7.2.43, X64 bit). Even more important, migrate to a version that is still in support. The LM-2200 series are like many older ones End of Life (EOL). Kemp still delivers important fixes for critical security issues like this year (7.1.35.5 and 7.1.35.6) but that’s it in long term support (LTS). This is not bad, these have been supported for a very long time but the aging 32-bit hardware has reached the point where replacing the is the only right thing to do.

With Kemp we can select new hardware, virtual machines or appliances in the cloud. So on-premises, hybrid and public cloud needs can be taken care off with the same familiar load balancer / Application delivery controller (ADC).

One technique to migrate Kemp workloads is to export the virtual services to templates and use these to configure the new solution. It is during that process we ran into an error: Kemp LoadMaster template import issue: Command serverinit needs 1 parameter(s)

Kemp LoadMaster template import issueCommand serverinit needs 1 parameter(s)

One of the applications is a mission critical one that has many different virtual services. FTP/FTPS/HTTP/HTTPS and also a bunch of TCP/UDP connectivity over ports that are very application/industry specific. A dozen virtual services, all on the same IP address with different ports and configuration needs.

We exported all of them to templates which we then used to recreate them on the replacement ADC. While doing so we used a different IP address for these newly created virtual services for testing purposes. This test IP address is changesd to the original production IP when ready to make the move and after disabling the old virtual services. That also allows for a quick exit / roll back if needed.

The process of creating a new virtual service requires a little work to be done still such as defining a gateway, SSL certificates, adding real servers, … but the bulk of the work is done for you.

But with certain templates we got an error: Syntax error detected in template file: Command serverinit needs 1 parameter(s)

clip_image001

When looking at the template in a text editor we see the following:

clip_image002

Clearly “servinit” does not have a parameter set. So, it probably needs one, to specify which type of the Server Initiating Protocol needs to be set for our generic service.

clip_image003

Finding a solution

We need to find out what parameter goes with our setting and add that the template. That value is found is easy enough. Via educated trial and error. On a test virtual service on the current version ADC we set the value for the Server Initiating Protocols to our value (other server initiating) and then export this virtual service to a template. We look at the template and note the number. That way we map what server initiating protocol corresponds to what value. In our case other server initiating is “3”.

clip_image004

We edit our exported templates to have the correct parameter value set that we find out this way and try to import it again.

clip_image005

That’s all that we needed to do to get these exported templates to be imported with no further issues.

clip_image006

clip_image008

All that’s left to do is to finish configuring the virtual service and continue our migration.

Conclusion

Don’t panic. Many problems you encounter have a solution, workaround or fix. Maybe this will help someone out there. Take care and until next time.3

A highly redundant Application Delivery Controller Setup with KempTechnologies

Posted on by
Reply

Introduction

The goal was to make sure the KempTechnologies LoadMaster Application Delivery Controller was capable to handle the traffic to all load balanced virtual machines in a high volume data and compute environment. Needless to say the solution had to be highly available.

A highly redundant Application Delivery Controller Setup with KempTechnologies

The environment offers rack and row as failure units in power, networking and compute. Hyper-V clusters nodes are spread across racks in different rows. Networking is high to continuously available allowing for planned and unplanned maintenance as well as failure of switches. All racks have redundant PDUs that are remotely managed over Ethernet. There is a separate out of band network with remote access.

The 2 Kemp LoadMasters are mounted a different row and different rack to spread the risk and maintain high availability. Eth0 & Eth2 are in active passive bond for a redundant management interface, eth1 is used to provide a secondary backup link for HA. These use the switch independent redundant switches of the rack that also uplink (VLT) to the Force10 switches (spread across racks and rows themselves). The two 10GBps ports are in an active-passive bond to trunked ports of the two redundant switch independent 10 Gbps switches in the rack. So we also have protection against port or cable failures.

image

Some tips: Use TRUNK for the port mode, not general with DELL switches.

This design allows gives us a lot of capabilities.We have redundant networking for all networks. We have an active-passive LoadMasters which means:

  • Failover when the active on fails
  • Non service interrupting firmware upgrades
  • The rack is the failure domain. As each rack is in a different row we also mitigate “localized” issues (power, maintenance affecting the rack, …)

Combine this with the fact that these are bare metal LoadMasters (DELL R320 with iDRAC –  see Remote Access to the KEMP R320 LoadMaster (DELL) via DRAC Adds Value) we have out of band management even when we have network issues. The racks are provisioned with PDU that are managed over Ethernet so we can even cut the power remotely if needed to resolve issues.

Conclusion

The results are very good and we get “zero ping loss” failover between the LoadMaster Nodes during testing.

We have a solid, redundant Application Deliver Controller deployment that does not break the switch independent TOR setup that exists in all racks/rows. It’s active passive on the controller level and active-passive at the network (bonding) level. If that is an issue the TOR switches should be configured as MLAGs. That would enable LACP for the bonded interfaces. At the LoadMaster level these could be configured as a cluster to get an active-active setup, if some of the restrictions this imposes are not a concern to your environment.

Important Note:

Some high end switches such as the Force10 Series with VLT support attaching single homes devices (devices not attached to both members on an VLT). While VLT and MLAG are very similar MLAGs come with their own needs & restrictions. Not all switches that support MLAG can handle single homed devices. The obvious solution is no to attach single homed devices but that is not always a possibility with certain devices. That means other solutions are need which could lead to a significant rise in needed switches defeating the economics of affordable redundant TOR networking (cost of switches, power, rack space, operations, …) or by leveraging MSTP and configuring a dedicates MSTP network for a VLAN which also might not always be possible / feasible so solve the issue. Those single homed devices might very well need to be the same VLANs as the dual homed ones. Stacking would also solve the above issue as the MLAG restrictions do not apply. I do not like stacking however as it breaks the switch independent redundant network design; even during planned maintenance as a firmware upgrade brings down the entire stack.

One thing that is missing is the ability to fail over when the network fails. There is no concept of a “protected” network. This could help try mitigate issues where when a virtual service is down due to network issues the LoadMaster could try and fail over to see if we have more success on the other node. For certain scenarios this could prevent long periods of down time.

Kemp LoadMaster OEM Servers and Dell Firmware Updates with Lifecycle Controller

Posted on by
1

When you buy a DELL OEM based Kemp Technologies LoadMaster you might wonder who will handle the hardware updates to the server. Well Dell handles all OEM updates via its usual options and as with all LoadMasters Kemp Technologies handles the firmware update of the LoadMaster image.

KempLM320

Hardware wise both DELL and Kemp have been two companies that excel in support. If you can find the solution that meets your needs it’s a great choice. Combine them and it make for a great experience.  Let me share a small issue I ran into updating Kemp Loadmaster OEM Servers and Dell Firmware Updates with Lifecycle Controller

For a set of DELL R320 loadmasters in HA is was upgrading ( I not only wanted to move to 7.1-Patch28b-BARE-METAL.bin but I also wanted to take the opportunity to bring the firmware of those servers to the latest versions as that had been a while (since they had been delivered on site).

There is no OS that runs in those server,s as they are OEM hardware based appliances for the Loadmaster image. No worries these DELL servers come with DRAC & Lifecycle controllers so you can leverage those to do the firmware updates from a Server Update Utility ISO locally, via virtual media, over over the network, via FTP or a network share. FTP is either the DELL FTP Site or an internal one.

image

image

Now as I had just downloaded the  latest SUU at the time (SUU-32_15.09.200.74.ISO – for now you need to use the 32 bit installers with the life cycle controller) I decided to just mount it via the virtual media, boot to the lifecycle controller and update using local media.

image

image

But I got stuck  …

It doesn’t throw an error but it just returns to the start point and nothing can fix it. Not even adding “/repository”  to the file path . You can type the name of an individual DUP (32 bit!) and that works. Scanning the entire repository however wouldn’t move beyond step 2 “Enter Access Details”.

Scanning for an individual DUP seemed to work but leaving the file path blank while trying to find all eligible updates seemed not to return any results so I could not advance. The way I was able to solve this was by leveraging the DRAC ability to update it own firmware using the firmware image file to the most recent version. I just got mine by extracting the DUP and taking the image file from the payload sub folder.

image

You can read on how to upgrade DRAC / Lifecycle Controller via the DRAC here.

image

When you’ve done that, I give the system a reboot for good measure, and try again. I have found in all my cases fixes the issue. My take on this is that older firmware can’t handle more recent SUU repositories. So give it a try if you run into this and you’ll be well on your way to get your firmware updated. If you need help with this process DELL has excellent documentation here in “Lifecycle Controller Platform Update/Firmware Update in Dell PowerEdge 12th Generation Servers”

image

image

image

The end result is a fully updated DELL Server / Kemp Loadmaster. Mission accomplished. All this can be done from the comfort of your home office. A win-win for both you and your customer/employer. Think about it, it would be a shame to miss out on all the benefits you get from working in the cloud when your on premises part of a hybrid infrastructure forces you to get in a car and drive to a data center 70 km away. Especially at 21:21 at night.

Quick Demo Video Of Site Failover With KEMP Loadmaster Global Balancing

Posted on by
3

Here’s a quick video that demonstrates how you can achieve site failover with via the KEMP Loadmaster Global Balancing feature. As long as you know what this can do for you and realize that it about site failover and high availability and not continuous availability without a second of service interruption you can deliver nice results with this technology across city campuses or between cities.

In our scenario we normally connect to the primary data center (weighted round robin) and fail over to the DRC when the primary site fails for some reason.

It’s very busy at the moment but I hope to address this topic a bit more in detail in the future. All of this runs virtualized on Hyper-V and performs just fine.