Database Migration Job for Kubernetes

Creates a Kubernetes Job to run database migrations.

Requirements

• The kubectl command line must be installed on the system. For AWS EKS and for normal Kubernetes.
• Access to a Kubernetes cluster to run the job.

Usage

Download the script and apply the execution permissions:

curl -L https://github.com/speedyrails/database-migration-job-kubernetes/raw/main/db-migration-job.sh -o db-migration-job.sh
chmod +x db-migration-job.sh

The script expects the following arguments:

• OCI_IMAGE:TAG: the OCI image to use in the job.
• K8s CONFIG MAP LIST: a Kubernetes configmaps name list separated by spaces with the environment variables required by the app.
• COMMAND_ENTRYPOINT: the entrypoint used by the job.
• COMMAND_ARGUMENT: the arguments passed to the entrypoint.

A optional argument can be passed to the script:

• MIGRATION_TIMEOUT: the length of time to wait before giving up. Zero means check once and don't wait, negative means wait for a week. The value must be in seconds. If not timeout provided the default value is 600 seconds.

To execute the job for database migrations:

./db-migration-job.sh "OCI_IMAGE:TAG" "K8s CONFIGMAP NAME LIST SEPARATED BY SPACES" "COMMAND_ENTRYPOINT" "COMMAND_ARGUMENT" "MIGRATION_TIMEOUT_SECONDS"

Examples

For apps built with Cloud Native Buildpacks, define the COMMAND_ENTRYPOINT as /cnb/lifecycle/launcher and COMMAND_ARGUMENT as bundle exec rake db:migrate; for instance:

./db-migration-job.sh "myapp:latest" "cm1 cm2 cm3" "/cnb/lifecycle/launcher" "bundle exec rake db:migrate"

For others build you can use /bin/bash or /bin/sh as the COMMAND_ENTRYPOINT; for instance:

./db-migration-job.sh "myapp:latest" "cm1 cm2 cm3" "/bin/bash" "bundle exec rake db:migrate"

To run a migration and wait 300 seconds for it to finish:

./db-migration-job.sh "myapp:latest" "cm1 cm2 cm3" "/bin/bash" "bundle exec rake db:migrate" "300"

License

MIT

Author Information

Speedyrails Inc.

By: Carlos M Bustillo Rdguez