Great question! You’re right that kubectl set image only targets the main application containers in a Deployment by default—init containers get left out of that command’s scope. But there are a couple of clean, kubectl-native ways to update your init container images to match the same URL you’re using for main containers.

Method 1: Use kubectl patch (Recommended for Automation/Scripting) #

The kubectl patch command lets you make targeted changes to specific parts of your Deployment manifest without editing the entire file. This is the closest equivalent to kubectl set image for init containers.

Update a single init container by index #

If you know the position of your init container in the list (index starts at 0), use this command:

kubectl patch deployment deployment_name --type='json' -p='[{"op": "replace", "path": "/spec/template/spec/initContainers/0/image", "value":"url_to_container"}]'

Update a specific init container by name (more reliable) #

To avoid relying on index positions (which can shift if you add/remove init containers later), target the container directly by its name:

kubectl patch deployment deployment_name --type='json' -p='[{"op": "replace", "path": "/spec/template/spec/initContainers/[name=your-init-container-name]/image", "value":"url_to_container"}]'

Update all init containers to the same image (batch changes) #

If you have multiple init containers and want to set all their images to the same URL, you can combine kubectl get with jq to generate a dynamic patch:

# Get the total number of init containers in the Deployment
INIT_CONTAINER_COUNT=$(kubectl get deployment deployment_name -o json | jq '.spec.template.spec.initContainers | length')

# Build the patch array
PATCH=$(for i in $(seq 0 $((INIT_CONTAINER_COUNT-1))); do echo -n '{"op": "replace", "path": "/spec/template/spec/initContainers/'$i'/image", "value":"url_to_container"},'; done | sed 's/,$//')

# Apply the patch to update all init containers
kubectl patch deployment deployment_name --type='json' -p="[$PATCH]"

Method 2: Use kubectl edit (Interactive, Quick Manual Changes) #

For one-off, manual updates, you can edit the Deployment directly in your default text editor:

kubectl edit deployment deployment_name

Locate the initContainers section in the manifest, update the image field to your desired URL, save the file, and exit. Kubernetes will automatically apply the changes immediately.

Key Note #

Unlike kubectl set image, which can update multiple main containers in a single command, you’ll need to specify each init container individually (or use the batch method above) when using kubectl patch. But it’s still a straightforward way to keep your init container images aligned with your main application images.

内容的提问来源于stack exchange，提问作者Max Woolf