This guide provides a step-by-step approach to resolve issues where K3s, Gateway, Longhorn, and other related pods fail to start due to a missing sandbox image: rancher/mirrored-pause:3.6.

The troubleshooting steps cover:

• Verifying the presence of image tar files
• Restarting the K3s service
• Validating the image imports into the containerd runtime

Problem

K3s, Gateway, or Longhorn pods are failing to start, and you may see an error similar to:

failed to get sandbox image "rancher/mirrored-pause:3.6"

Possible Causes

This error usually occurs when:

• K3s base images are missing or accidentally deleted from the node/Cluster.
• The system cannot pull the required images from the internet (e.g., due to air-gapped environment or network restrictions).

Troubleshooting Steps

Ensure the user is logged in as root or has sudo privileges before proceeding.

Step 1: Check for Image Tar File

If you are using the OpsRamp-provided ISO, verify that the image tar file exists in the following directory:

/var/lib/rancher/k3s/agent/images/

Sample Responce:

ls /var/lib/rancher/k3s/agent/images/
k3s-airgap-images-amd64-1.29.0.tar

Step 2: Restart K3S Service

If the image tar file is present, restart the K3s service to trigger the image import:

systemctl restart k3s

Step 3: Verify Imported Images

After restarting, K3s should automatically import the images into the containerd runtime. You can verify the imported images using the following command:

k3s ctr i ls -q

Sample Responce:

docker.io/rancher/klipper-helm:v0.8.2-build20230815
docker.io/rancher/klipper-lb:v0.4.4
docker.io/rancher/local-path-provisioner:v0.0.24
docker.io/rancher/mirrored-coredns-coredns:1.10.1
docker.io/rancher/mirrored-library-busybox:1.36.1
docker.io/rancher/mirrored-library-traefik:2.10.5
docker.io/rancher/mirrored-metrics-server:v0.6.3
docker.io/rancher/mirrored-pause:3.6

Ensure that rancher/mirrored-pause:3.6 is listed. If not, the image has not been properly imported.