Deploying to Google Kubernetes Engine

This guide describes how to pull images from Artifact Registry to deploy to Google Kubernetes Engine. If you want to deploy to self-hosted or third-party Kubernetes services, you must configure authentication to Google Cloud before pulling images from Artifact Registry. To authenticate to Google Cloud from Kubernetes workloads outside Google Cloud, see Configure Workload Identity Federation with Kubernetes.

Google Kubernetes Engine can pull images directly from Docker repositories. Some versions include pre-configured support for pulling images from Artifact Registry Docker repositories.

Requirements

This section describes requirements to integrate with GKE.

Permissions

GKE uses the following defaults when you create node pools or clusters:

The Compute Engine default service account is the identity for nodes. This default service account has the IAM basic Editor role, if you have not disabled this behavior.
Nodes that you create with the default service account have the Compute Engine default access scopes, including read-only access to storage. You cannot change access scopes on existing nodes.

If you use these defaults, GKE can pull images from Artifact Registry repositories in the same Google Cloud project. If you need to push images from nodes, pull or push images across projects, use a user-provided service account, or have other needs that the default settings don't support, see the access control documentation for information about configuring access.

GKE version

The following table lists the minimum required GKE versions to create clusters that have default permissions to pull containers from Docker repositories in the same project.

Version	Minimum required patch
1.14	1.14.10-gke.22
1.15	1.15.9-gke.8

If your version of GKE is earlier than the minimum version, you must configure Kubernetes imagePullSecrets to enable GKE to pull images.

If GKE is in a different project than Artifact Registry, grant Artifact Registry permissions to the service account that your GKE node use. By default, nodes use the Compute Engine default service account.

Running an image

You can run a Artifact Registry image on a Google Kubernetes Engine cluster using the following command:

kubectl run [NAME] --image=LOCATION-docker.pkg.dev/PROJECT-ID/REPOSITORY/IMAGE:TAG

where:

LOCATION is the regional or multi-regional location of the repository.
PROJECT is your Google Cloud console project ID. If your project ID contains a colon (:), see Domain-scoped projects.
REPOSITORY is the name of the repository where the image is stored.
IMAGE is the name of the image in the repository.
TAG is the tag for the image version that you want to pull.

For more information about Kubernetes commands, see Overview of kubectl.

Troubleshooting containerd node images

Starting with GKE node version 1.19, the default node image for Linux nodes is the Container-Optimized OS with containerd (cos_containerd) variant instead of the Container-Optimized OS with Docker (cos) variant.

While the Docker binary is available on Linux nodes that use containerd as a runtime, we don't recommend using it. Docker does not manage the containers Kubernetes runs on containerd nodes, thus you cannot use it to view or interact with running Kubernetes containers using Docker commands or the Docker API.

For debugging or troubleshooting on Linux nodes, you can interact with containerd using the portable command-line tool built for Kubernetes container runtimes: crictl. crictl supports common functionalities to view containers and images, read logs, and execute commands in the containers.

For more information, refer to the crictl user guide and the GKE documentation on containerd.

For Windows Server nodes, the containerd daemon runs as a Windows service named containerd. Logs are available in the following logs directory: C:\etc\kubernetes\logs\containerd.log and are shown in Logs Explorer under LOG NAME: "container-runtime".

Pulling from a public Artifact Registry repository

Once you have deployed and image to a GKE cluster with containerd nodes, you can connect to a VM instance using SSH and run crictl commands for troubleshooting.

Public Artifact Registry repositories don't require authentication. crictl can also be used to pull images in private Artifact Registry repositories.

Console

In the Google Cloud console, go to the VM Instances page.

Go to VM Instances
In the list of virtual machine instances, click the arrow next to SSH in the row of the instance that you want to connect to.

Note: When you connect to VMs using the Google Cloud console, Compute Engine creates an ephemeral SSH key for you. For more information about SSH keys, see SSH connections to Linux VMs
Select "Open in browser window" or the connection method of your choice from the drop down options.
Google Cloud console opens a new terminal window. Use crictl to pull an image from Artifact Registry:
```
crictl pull IMAGE_LOCATION:TAG
```
The output looks like the following:
```
Image is up to date for sha256:0f25067aa9c180176967b4b50ed49eed096d43fa8c17be9a5fa9bff05933bee5
```
When you pull an image from an Artifact Registry private repository, you must authenticate to the repository. You can use an access token to provide your credentials.

gcloud

Ensure that you have the latest version of the Google Cloud CLI
```
gcloud components update
```
Connect to the VM:
```
gcloud compute ssh --project=PROJECT_ID \
 --zone=ZONE \
 VM_NAME
```
Replace the following:
- PROJECT_ID: the ID of the project that contains the VM
- ZONE: the name of the zone in which the VM is located
- VM_NAME: the name of the VM
If you have set default properties for the Google Cloud CLI, you can omit the --project and --zone flags from this command. For example:
```
gcloud compute ssh VM_NAME
```
If you have not already created a SSH key, SSH keygen will generate one for you. Enter a passphrase or leave empty when prompted.
Use crictl to pull an image from Artifact Registry:
```
crictl pull IMAGE_LOCATION:TAG
```
The output looks like the following:
```
Image is up to date for sha256:0f25067aa9c180176967b4b50ed49eed096d43fa8c17be9a5fa9bff05933bee5
```
When you pull an image from an Artifact Registry private repository, you must authenticate to the repository. You can use an access token to provide your credentials.

Pulling from a private Artifact Registry repository

Console

In the Google Cloud console, go to the VM Instances page.

Go to VM Instances
In the list of virtual machine instances, click the arrow next to SSH in the row of the instance that you want to connect to.

Note: When you connect to VMs using the Google Cloud console, Compute Engine creates an ephemeral SSH key for you. For more information about SSH keys, see SSH connections to Linux VMs
Select "Open in browser window" from the drop down options.

Google Cloud console opens a new terminal window. Generate a Compute Engine service account access token using curl.

curl -s "http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/token" -H "Metadata-Flavor: Google"

The output looks like the following example:

"access_token":"ya29.c.KpkBCQgdwv6LrZ2tjrCpG6snWwPMX29LzMeUmAV_Hq_XaxUurfXcCfGZfASGh_KbdmUYTvkuV3sh-WaSBplEskdP6Tc
HDsTv4B9hMyvoL4M9HrzKHuKTa1ZGj_3iQ1lwq_dAMxAPGjxEVKexatwN2KP0EAWyb6R55Cuu8ItgLf9f4pm9lC5zH4Qo0fkxPUsnCGRBe4AYxEpN6T
sh","expires_in":3526,"token_type":"Bearer"}

Copy the value of the access_token from the returned output without the quotation marks.

Pull the image using crictl pull --creds and the access_token value copied in the previous step.

crictl pull --creds "oauth2accesstoken:ACCESS_TOKEN" IMAGE_LOCATION:TAG

The output looks like the following:

Image is up to date for sha256:0f25067aa9c180176967b4b50ed49eed096d43fa8c17be9a5fa9bff05933bee5

gcloud

Ensure that you have the latest version of the Google Cloud CLI
```
gcloud components update
```
Connect to the VM:
```
gcloud compute ssh --project=PROJECT_ID \
 --zone=ZONE \
 VM_NAME
```
Replace the following variables:
- PROJECT_ID: the ID of the project that contains the VM
- ZONE: the name of the zone in which the VM is located
- VM_NAME: the name of the VM
If you have set default properties for the Google Cloud CLI, you can omit the --project and --zone flags from this command. For example:
```
gcloud compute ssh VM_NAME
```
If you have not already created a SSH key, SSH keygen will generate one for you. Enter a passphrase or leave empty when prompted.

Generate a Compute Engine service account access token using curl.

curl -s "http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/token" -H "Metadata-Flavor: Google"

The output looks like the following:

"access_token":"ya29.c.KpkBCQgdwv6LrZ2tjrCpG6snWwPMX29LzMeUmAV_Hq_XaxUurfXcCfGZfASGh_KbdmUYTvkuV3sh-WaSBplEskdP6Tc
HDsTv4B9hMyvoL4M9HrzKHuKTa1ZGj_3iQ1lwq_dAMxAPGjxEVKexatwN2KP0EAWyb6R55Cuu8ItgLf9f4pm9lC5zH4Qo0fkxPUsnCGRBe4AYxEpN6T
sh","expires_in":3526,"token_type":"Bearer"}

Copy the value of the access_token from the returned output without the quotation marks.

Pull the image using crictl pull --creds and the access_token value copied in the previous step.

crictl pull --creds "oauth2accesstoken:ACCESS_TOKEN" IMAGE_LOCATION:TAG

The output looks like the following:

Image is up to date for sha256:0f25067aa9c180176967b4b50ed49eed096d43fa8c17be9a5fa9bff05933bee5

crictl lets developers debug their runtime without needing to set up Kubernetes components. For a full list of commands, see the crictl docs and the Kubernetes debugging docs.