CODEWITHSUNDEEP
kubernetesgoogle-cloud-platformcloudgoogle-deployment-manager
warrior22123
warrior22123

Reputation: 27

Running startup-scripts on Kubernetes Clusters

How do I run a start script on Kubernetes cluster? I saw that there are ways to run start scripts on compute instances but couldn't find any documentation regarding the same for kubernetes clusters.

Upvotes: 1

Views: 4122

Answers (1)

Arghya Sadhu
Arghya Sadhu

Reputation: 44687

You can use init containers to execute script before the actual container is started.

Init containers are specialized containers that run before app containers in a Pod . Init containers can contain utilities or setup scripts not present in an app image.

Because init containers have separate images from app containers, they have some advantages for start-up related code:

  • Init containers can contain utilities or custom code for setup that are not present in an app image. For example, there is no need to make an image FROM another image just to use a tool like sed, awk, python, or dig during setup.
  • The application image builder and deployer roles can work independently without the need to jointly build a single app image.
  • Init containers can run with a different view of the filesystem than app containers in the same Pod. Consequently, they can be given access to Secrets that app containers cannot access.
  • Because init containers run to completion before any app containers start, init containers offer a mechanism to block or delay app container startup until a set of preconditions are met. Once preconditions are met, all of the app containers in a Pod can start in parallel.
  • Init containers can securely run utilities or custom code that would otherwise make an app container image less secure. By keeping unnecessary tools separate you can limit the attack surface of your app container image.

Upvotes: 4

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