Configuring Deployment Scripts

The section Deployment Scripts allows you to administer the scripts that the Solution Manager uses to enable and disable servers or clusters in the load balancer.

Dialog to configure the scripts that deal with the load balancer

Dialog to configure the scripts that deal with the load balancer

According to the number of clusters in your environment, only a couple of scripts will be relevant:

  • Environments with one cluster: Solution Manager will use scripts Enable server in the load balancer and Disable server in the load balancer.
  • Environments with more than one cluster: Solution Manager will use scripts Enable cluster in the load balancer and Disable cluster in the load balancer.

To add a script to the Solution Manager, unfold the corresponding panel and drag and drop the file with the script inside the drop area.

Dialog to add a deployment script

Dialog to add a deployment script

Each deployment script can declare a list of parameters. To add a new parameter, click the new-argument-text-btn button and complete the form that the Solution Manager will open. An argument is defined with the following fields:

  • Name: A descriptive name for the parameter.

  • Type: Solution Manager supports two kind of arguments:

    • Use a Literal argument when you want to specify the actual value for the parameter. You should type the value of the argument in the field Value and select the check box Encrypted literal value if you want that the Solution Manager stores it in encrypted format.

      Dialog to add a new literal argument to a deployment script

      Dialog to add a new literal argument to a deployment script

    • Use a Load Balancing Variable when you want to reuse one of the variables defined in the Load Balancing Variables dialog. Take into account that the scripts that enable or disable clusters in the load balancer can only receive cluster load balancing variables as parameters. Nevertheless, those scripts that enable or disable servers in the load balancer can receive both cluster and server load balancing variables.

      Dialog to add a new load balancing variable argument to a deployment script

      Dialog to add a new load balancing variable argument to a deployment script

The Solution Manager will preserve the order of the arguments when executes the script. In the arguments table, you can use its first column to drag and drop an argument and reorder it.

Reordering an argument of a deployment script

Reordering an argument of a deployment script

Important

The Solution Manager follows the convention that any successful script execution returns the exit code 0 value. Any other exit code will be considered an error in execution.

Examples of Deployment Scripts

Imagine we are a corporation with a large Denodo deployment that uses F5 as its load balancer. We have two environments: one for development and one for production. Let’s see how to configure the deployment scripts in the Solution Manager and how the final scripts look like.

The development environment consists of one cluster with two Virtual DataPort servers, so we need to provide two scripts, one to disable a server in the load balancer and another one to enable it.

The script below is an example of how to disable a server in the load balancer. It connects via SSH to the machine where the load balancer resides, disables the server in the load balancer and captures any error during the execution.

Example script to disable a server in F5
@echo off

plink -ssh %1@%3 -pw %2 "tmsh modify /ltm node %4 state user-down session user-disabled" 1>&2

SET err_code=%ERRORLEVEL%
if %err_code% == 0 (
  echo OK
) else (
  echo Error 1>&2
)

exit %err_code%

This script depends on the following four parameters:

  1. Login of the user that connects via SSH to the load balancer machine.
  2. Password of the user that connects via SSH to the load balancer machine.
  3. IP or hostname of the load balancer machine.
  4. IP or logical name of the Virtual DataPort server in the load balancer.

Therefore, your Disable server in the load balancer script in the Deployment Scripts section should look like the figure below, considering that you have defined some cluster load balancing variables for its username, password and IP.

Script configuration to disable the server in F5

Script configuration to disable the server in F5

The script that will allow you to enable a server in the load balancer again is pretty similar to the previous one, as you can see in the following example:

Example script to enable a server in F5
@echo off

plink -ssh %1@%2 -pw %3 "tmsh modify /ltm node %4 state user-up session user-enabled " 1>&2

SET err_code=%ERRORLEVEL%
if %err_code% == 0 (
  echo OK
) else (
  echo Error 1>&2
)

exit %err_code%

The production environment of our corporation counts with several clusters. Therefore, we need to provide a couple of scripts to disable a cluster in the load balancer and to enable it again.

The service provided by the Denodo Platform is modeled in the cluster as three virtual servers that give access to the platform via HTTP, JDBC and ODBC in a pooled way. To disable a cluster, we need to disable these virtual servers in the load balancer.

The script below illustrates how to disable a cluster in the load balancer. It connects via SSH to the load balancer machine, disables the three virtual servers and captures any error during the whole process. Note that the last step is more complex than before, since any sentence of the three that disable one virtual server may fail.

Example script to disable a cluster in F5
@echo off

SET tempFileName=temp%RANDOM%.txt

plink -ssh %1@%3 -pw %2 "tmsh modify /ltm virtual %4 disabled; tmsh modify /ltm virtual %5 disabled; tmsh modify /ltm virtual %6 disabled; " 2> %tempFileName%

SETLOCAL EnableDelayedExpansion
SET errorString=
for /f "delims=" %%x in (%tempFileName%) do SET errorString=!errorString!%%x
SETLOCAL DisableDelayedExpansion

DEL %tempFileName%

if "%errorString%" == "" (
  echo OK
  exit 0
) else (
  echo Error "%errorString%" 1>&2
  exit 1
)

This script depends on the following six parameters:

  1. Login of the user that connects via SSH to the load balancer machine.
  2. Password of the user that connects via SSH to the load balancer machine.
  3. IP or hostname of the load balancer machine.
  4. Name of the HTTP virtual server in the load balancer.
  5. Name of the JDBC virtual server in the load balancer.
  6. Name of the ODBC virtual server in the load balancer.

In the Solution Manager, you should add the previous script in the Disable cluster in the load balancer dialog and configure their six arguments, like in the following figure.

Script configuration to disable the cluster in F5

Script configuration to disable the cluster in F5

Finally, you should repeat the process with the script that enables the cluster in the load balancer, which should look like the following piece of code:

Example script to enable a cluster in F5
@echo off

SET tempFileName=temp%RANDOM%.txt

plink -ssh %1@%3 -pw %2 "tmsh modify /ltm virtual %4 enabled; tmsh modify /ltm virtual %5 enabled; tmsh modify /ltm virtual %6 enabled; " 2> %tempFileName%

SETLOCAL EnableDelayedExpansion
SET errorString=
for /f "delims=" %%x in (%tempFileName%) do SET errorString=!errorString!%%x
SETLOCAL DisableDelayedExpansion

DEL %tempFileName%

if "%errorString%" == "" (
  echo OK
  exit 0
) else (
  echo Error "%errorString%" 1>&2
  exit 1
)