notes for lecuture on writing yaml files for managing kubernetes clusters

kubectl apply -f=deployment.yaml

• run deployment on connected cluster
• -f is for file
• to update simply reapply same command

pullImageOption

The imagePullPolicy for a container and the tag of the image affect when the kubelet attempts to pull (download) the specified image.

pullImageOption:always

every time the kubelet launches a container, the kubelet queries the container image registry to resolve the name to an image digest. If the kubelet has a container image with that exact digest cached locally, the kubelet uses its cached image; otherwise, the kubelet pulls the image with the resolved digest, and uses that image to launch the container

remember that you do not control deployments with a service! services control pods.

without services Pods are hard to reach and communicate with.

kubectl apply -f=service.yaml

• create service object

you can delete imperatively using the service or deployment name. eg.

kubectl delete deployment first-app-deployment

or you can you can use the .yaml files to specify which objects you want to remove

kubectl delete -f=deployment.yaml,service.yaml

you can also use labels

kubectl delete deployments,services -l group=example