GCP, Common labels for all project resources
Please have a look at the documentation Creating and managing labels:
A label is a key-value pair that helps you organize your Google Cloud instances. You can attach a label to each resource, then filter the resources based on their labels. Information about labels is forwarded to the billing system, so you can break down your billing charges by label.
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Here are some common use cases for labels:
Team or cost center labels: Add labels based on team or cost center to distinguish instances owned by different teams (for example,
team:researchandteam:analytics). You can use this type of label for cost accounting or budgeting.Component labels: For example,
component:redis,component:frontend,component:ingest, andcomponent:dashboard.Environment or stage labels: For example, environment:production and environment:test.
State labels: For example,
state:active,state:readytodelete, andstate:archive.Virtual machine labels: A label can be attached to a virtual machine. Virtual machine tags that you defined in the past will appear as a label without a value.
Is it possible to label all project resources with some 'common' labels which can be redefined on resource level?
You can set labels on the resources when you create them or you can add labels to already created resources. Unfortunately you're not able to label all GCP resources. You can find more details in the documentation Creating and managing labels, section Services currently supporting labels. You can use API calls, gcloud commands and the Console to set/change/remove labels from any resources that support it.
It may looks like labels inheritance/override
Unfortunately there's no "inheritance/override", but you can have a few labels for one resource. For example for a GCP VM:
gcloud compute instances add-labels example-instance --labels = label0 = value0, label2 = value1
Please have a look at the documentation Labeling resources to find more details about labeling GCE resources.
I hope it was helpful.