Image
Learn about images.
All Vela steps will require an image declaration to be provided.
The image: tag is a key component that defines the Docker Image you want to be executed during the step.
The default behavior is for a Vela worker to pull an image if it is not present on the host. Docker daemon’s cache image layers locally, by allowing the default behavior to use the cache you can get the advantage of faster build start up times.
Sometimes this isn’t the desired behavior and you want the image to always be pulled or pulled at a specific point in the pipeline lifecycle.
That’s when you can use the pull: tag to set the policy for how/when the image pull interaction should be treated.
Expand your knowledge with an example!
# All the below syntaxes would pull an image.
image: alpine
image: alpine:latest
image: alpine:3
image: library/alpine:3
image: index.docker.io/library/alpine
image: index.docker.io/library/alpine:3
# This is telling Vela to pull the image at the beginning of the pipeline always.
- name: always pull the image
image: alpine
pull: always
commands:
- echo "Welcome to the Vela docs"
# This is telling Vela to pull the image just before executing the step
- name: pull the image on start
image: alpine
pull: on_start
commands:
- echo "Welcome to the Vela docs"