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Pruning Modes

This document holds a detailed step-by-step guide to deploy the medium-sized static deployment variant of a webshop application to showcase the Consistent-Loose Pruning Mode. The webshop application can be deployed in the following deployment variants.

  • static with medium resources on a single virtual machine on a local OpenStack (OS) instance
  • static with large resources on a single virtual machine on a local OpenStack (OS) instance
  • elastic with high availability and backups on Google Cloud Platform (GCP)

Requirements

We need to fulfill the following requirements to follow this step-by-step guide.

  • Linux machine, e.g., Ubuntu 22.04
  • Access to an OpenStack instance

Preparation

First, we install OpenTOSCA Vintner. For more information see Installation.

curl -fsSL https://vintner.opentosca.org/install.sh | sudo bash -

Next, install xOpera.

vintner setup install --xopera

Next, we configure xOpera as the orchestrator that should be used for the deployment.

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vintner orchestrators init xopera --no-venv
vintner orchestrators enable --orchestrator xopera
vintner orchestrators attest --orchestrator xopera

Import the Template

Figure 1: The Variability4TOSCA model of our webshop.

First, we import the Variability4TOSCA template.

vintner templates import --template pruning-mode --path examples/xopera-pruning-consistent-loose

Then, we initialize an application instance.

vintner instances init --instance pruning-mode --template pruning-mode

We can optionally inspect the Variability4TOSCA model. This model contains all possible elements having conditions assigned. However, due to pruning, only a handful of condition must be modeled, e.g., the condition checking if a medium or large virtual machine is required. This is shown in Figure 1.

vintner templates inspect --template pruning-mode

Resolve Variability

Figure 2: The medium-sized static deployment variant of the webshop.

We want to deploy the medium-sized static variant of the webshop application using GCP. We specify this when resolving variability as follows.

vintner instances resolve --instance pruning-mode --presets static

You can optionally inspect the generated TOSCA-compliant model. This template contains only the elements required for the elastic variant, e.g., the MySQL database. This is shown in Figure 2.

vintner instances inspect --instance pruning-mode

Deploy the Application

Finally, we can deploy the elastic variant. Therefore, we need to provide deployment inputs, e.g., credentials to OpenStack. These inputs are specified in topology_template.inputs of the TOSCA-compliant model. The following inputs must be defined.

os_compute_network: <OS_COMPUTE_NETWORK>
os_compute_security_groups: <OS_COMPUTE_SECURITY_GROUPS>
os_compute_key_name: <OS_COMPUTE_KEY_NAME>
os_compute_ssh_user: <OS_COMPUTE_SSH_USER>
os_compute_ssh_key_file: <OS_COMPUTE_SSH_KEY_FILE>
os_region_name: <OS_REGION_NAME>
os_auth_type: <OS_AUTH_TYPE>
os_auth_url: <OS_AUTH_URL>
os_identity_api_version: <OS_IDENTITY_API_VERSION>
os_interface: <OS_INTERFACE>
os_application_credential_id: <OS_APPLICATION_CREDENTIAL_ID>
os_application_credential_secret: <OS_APPLICATION_CREDENTIAL_SECRET>

# Also required. Just fill them with dummy values.
database_password: <DATABASE_PASSWORD>
gcp_region: <GCP_REGION>
gcp_service_account_file: <GCP_SERVICE_ACCOUNT_FILE>
gcp_project: <GCP_PROJECT>
gcp_auto_scaling: <GCP_AUTO_SCALING>

Next, start the deployment. The deployment will take around 5 minutes.

vintner instances deploy --instance pruning-mode --inputs ${INPUTS_PATH}

Test the Application

Next, we can test that the application is correctly working. Therefore, find out the hostname of the provisioned virtual machine.

curl --fail-with-body http://${HOSTNAME_OF_VM}:3000

If no hostname has been assigned, then use the IPv4 address.

curl --fail-with-body http://[${IPv4_ADDRESS_OF_VM}]:3000

This should return the following.

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{
   "MESSAGE": "Successfully executed query",
   "QUERY": "SELECT 1 + 1;",
   "DB_DIALECT": "sqlite",
   "DB_NAME": "shop",
   "DB_ADDRESS": "/var/lib/sqlite-databases/shop.db",
   "DB_USERNAME": "root",
   "DB_PASSWORD": "5e88"
}

We can observe the following.

  • according to MESSAGE, the query has been successful
  • according to DB_DIALECT, the SQLite has been used as dialect
  • according to DB_ADDRESS, a local SQLite database has been used

Thus, we conclude that the application has been deployed as desired.

Undeploy the Application

Afterward, we can undeploy the application.

vintner instances undeploy --instance pruning-mode

We can also optionally remove the instance or cleanup the filesystem. Note, cleaning up the filesystem removes any vintner data including, e.g., all imported templates and created instances.

vintner instances delete --instance pruning-mode
vintner setup clean --force

Logs

This deployment is also executed in our integration pipeline, which is executed once a week. The logs of the corresponding GitHub action can be accessed here. Relevant jobs start with "xOpera Pruning Mode". Note, a GitHub account is required to access these logs. The raw logs are available without requiring an GitHub account.

Zenodo

The assets of this guide can be also found on Zenodo.

Publication

This guide is part of our paper published at the CLOSER 2024. Also check our other publications.


Last update: February 29, 2024