mmmmmmpc / forklift-configmap-service

Systemd service to run in VMs on KubeVirt to mount ConfigMaps

forklift-configmap-service

Systemd service to run in VMs on KubeVirt to mount ConfigMaps and execute automation steps included in them.

Installation

The script configmap-service-install.sh can be used to install configmap-service. To install it in a Linux system with systemdsimply run

./configmap-service-install.sh

This will copy the script, install the service, apply correct permissions, reload systemd and leave it ready to run.

In case you want to package it and install it somewhere else, you can pass a target folder to it

./configmap-service-install.sh /tmp

Then it will just copy the files to the target folders, recreating the relative paths. (Useful for packaging)

Installation in Red Hat Enterprise Linux 8 (RHEL8)

To install the service in different RPM based distros, there is a Forkift ConfigMap Service Repo Available. To make things easy a repo file is provided for RHEL8 users mperezco-forklift-configmap-service-epel-8.repo. To use it follow these steps:

cp mperezco-forklift-configmap-service-epel-8.repo /etc/yum.repos.d/
yum install configmap-service -y

... or

dnf copr enable mperezco/forklift-configmap-service
dnf install configmap-service -y

Manual Instalation

1. Copy script configmap-service.sh to /usr/sbin/configmap-service.sh
2. Copy service file configmap.service to /etc/systemd/system/configmap.service
3. Edit service to modify After so it runs once the main service is started (i.e. OracleDB or PostgreSQL)
4. Reload service files systemctl daemon-reload
5. Assign a ConfigMap to the VM like the template provided configmap-sample.yaml

Configuration

The configmap-service is intended to be run after the main service in the VM is running (i.e. a Database) so it can apply changes to it. A default configuration is provided and deployed to /etc/systemd/system/configmap.service in command line installations and to /var/lib/systemd/system/configmap.service in RPM based installations.

To customize the starting up of the service, we shall create the directory /etc/systemd/system/configmap.service.d/, and then create the file postgresql.conf with the following content:

[Unit]
After=postgresql.service

The apply changes:

systemctl daemon-reload

More info in the official documentation for RHEL8

This way, the service will run once the database is active and we can perform actions such as preload data to it from our ConfigMap, Label it as DEV/TEST/PROD or even change the database schema.

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