Pushing and pulling images in GCP - Step-by-Step Execution

Process Flow - Pushing and pulling images

Build Docker Image

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Tag Image with Registry URL

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Authenticate with GCP Registry

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Push Image to Registry

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Image Stored in Registry

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Pull Image from Registry

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Use Image Locally or in Cloud

This flow shows how you build a Docker image, tag it for Google Container Registry, authenticate, push it to the registry, and then pull it back for use.

Execution Sample

GCP

docker build -t gcr.io/my-project/my-app:v1 .
gcloud auth configure-docker
docker push gcr.io/my-project/my-app:v1
docker pull gcr.io/my-project/my-app:v1

Builds a Docker image, authenticates with GCP, pushes it to Google Container Registry, then pulls it back.

Process Table

Step	Command	Action	Result	Notes
1	docker build -t gcr.io/my-project/my-app:v1 .	Build image locally	Image 'my-app:v1' created	Image built and tagged, ready to push
2	gcloud auth configure-docker	Authenticate with GCP Registry	Docker configured for gcr.io	Required before push to GCR
3	docker push gcr.io/my-project/my-app:v1	Push image to GCR	Image uploaded to gcr.io/my-project/my-app:v1	Requires prior authentication
4	docker pull gcr.io/my-project/my-app:v1	Pull image from GCR	Image downloaded locally	Image ready to run or deploy
5	-	End of process	Image is stored in registry and local cache	Process complete

💡 Process stops after image is pushed and pulled successfully.

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
Local Image	None	my-app:v1 (built)	my-app:v1 (built)	my-app:v1 (built)	my-app:v1 (pulled)	my-app:v1 (available)
Registry Image	None	None	None	my-app:v1 (uploaded)	my-app:v1 (uploaded)	my-app:v1 (stored)
Authentication	Not Authenticated	Not Authenticated	Authenticated	Authenticated	Authenticated	Authenticated

Key Moments - 3 Insights

Why do we need to tag the image with the registry URL before pushing?

Tagging the image with the registry URL tells Docker where to send the image. Without this, Docker won't know which registry to push to. See execution_table step 1 and 3.

What happens if you try to push without authenticating?

The push will fail because the registry requires permission. Authentication must happen before pushing. See variable_tracker Authentication changes at step 2.

After pulling the image, is it available locally to run?

Yes, pulling downloads the image to your local machine so you can run or deploy it. See execution_table step 4 and variable_tracker Local Image after step 4.

Visual Quiz - 3 Questions

Look at the execution_table, what is the result after step 3?

A Image uploaded to gcr.io/my-project/my-app:v1

B Image built locally

C Image downloaded locally

D Authentication failed

💡 Hint

Check the 'Result' column for step 3 in the execution_table.

According to variable_tracker, when does authentication happen?

A After step 1

B After step 2

C After step 3

D At the start

💡 Hint

Look at the 'Authentication' row and see when it changes from 'Not Authenticated' to 'Authenticated'.

If you skip tagging the image with the registry URL, what will happen?

A Image will be pushed but with a wrong name

B Docker will push to the default registry

C Push will fail because registry is unknown

D Image will be pulled instead of pushed

💡 Hint

Refer to key_moments about tagging importance and execution_table step 1 and 3.

Concept Snapshot

Pushing and Pulling Images in GCP:
1. Build your Docker image locally.
2. Tag it with your GCP registry URL (gcr.io/project/image:tag).
3. Authenticate with GCP to allow push.
4. Push the image to Google Container Registry.
5. Pull the image anytime to use it locally or in cloud deployments.

Full Transcript

This lesson shows how to push and pull Docker images using Google Cloud Platform's Container Registry. First, you build a Docker image on your local machine. Then, you tag the image with the registry URL so Docker knows where to send it. Next, you authenticate with GCP to get permission to push. After authentication, you push the image to the registry where it is stored. Later, you can pull the image back to your local machine to run or deploy it. The execution table traces each step, showing commands, actions, and results. The variable tracker shows how the local image, registry image, and authentication state change over time. Key moments clarify why tagging and authentication are necessary. The quiz tests understanding of these steps and their order.