This blog contains experience gained over the years of implementing (and de-implementing) large scale IT applications/software.

How an Azure hosted SAP LaMa Controlled SAP System Starts Up

We all know how this works in the old “pre-cloud” world.
To start a SAP system on a physical server which is currently shutdown, you would:

  1. Power on the physical host (through whatever means, ILO or a button or other).
  2. You log into the host as “adm” and run: “sapcontrol -nr ## -function StartSystem”.

We then moved from physical, to virtual:

  1. Power on the hypervisor physical host (through whatever means, ILO or a button or other).
  2. Power on the VM.
  3. You log into the VM as “adm” and run: “sapcontrol -nr ## -function StartSystem”.

Now we have cloud:

  1. Power on the VM (through cloud control software e.g. Azure Portal).
  2. You log into the VM as “adm” and run: “sapcontrol -nr ## -function StartSystem”.

How Does SAP LaMa Work In this Context?

With SAP LaMa, it has the ability to perform both steps #1 and #2 in the last list.
Here’s a diagrammatic overview that I hope shows accurately the interaction between the Azure,  Linux and SAP layers:

In the above diagram we can see that SAP LaMa is “cloud aware” and uses the Azure APIs to start and stop Azure VMs.

Once the VM is started, the usual Linux-level startup process takes over to start the services.

There is one caveat with the above and that is regarding SUSE cloud-netconfig. Find out more here: SUSE Cloud-Netconfig and Azure VMs – Dynamic Network Configuration

Why the Hostagent is Critical for LaMa

The SAP Hostagent is used as the marker point in the VM start-up process, at which point SAP LaMa knows for sure that the VM is up and running.
Before the Hostagent responds, SAP LaMa can only query the status of the VM from the Azure APIs, which basically say “starting” or “running”.

There are a number of monitoring capabilities inside SAP LaMa, but the Hostagent is the critical one.
From the Hostagent, the SAP instance agents can be unregistered and re-registered.

When setting up your SAP LaMa landscape, the SAP Hostagent is critical.  If you get it right, with automated deployment, SSL setup, common configuration, custom descriptors/operations, then you can automate almost anything in your SAP landscape.  

You need to constantly patch the SAP Hostagent to ensure that it remains compatible with other elements of your SAP landscape.  For example, to be able to patch the SAP ASE database, you need the Hostagent.  It’s also used for the BALDR (metrics gathering) inside SAP ASE from ASE 16.3 onwards.

SAP LaMa & SAP Landscape Orchestration

The SAP LaMa tool is the nice front-end and scheduler onto which you can apply your automation requirements via the Hostagent and SAP instance agents.

Not only does it provide orchestration capability, but it can also validate your landscape according to predefined in-built checks (such as Kernel component version consistency) and even validate against custom validations built and defined by you.